PRACTICAL POINTERS
FOR
PRIMARY CARE
ABSTRACTED MONTHLY FROM THE JOURNALS
JUNE 2005
ANTIBIOTIC PRESCRIBING STRATEGIES FOR ACUTE LOWER RESPIRATORY
INFECTION
USE OF WAIST CIRCUMFERENCE TO PREDICT INSULIN RESISTANCE
SENSITIVITY, SPECIFICITY, AND PREDICTIVE VALUES A Review
ROUTINE USE OF PROPHYLACTIC LOW-DOSE ASPIRIN
THE QUALITY OF ANTIPSYCHOTIC DRUG PRESCRIBING IN NURSING HOMES
THRESHOLDS FOR NORMAL BLOOD PRESSURE AND SERUM
CHOLESTEROL.
ANTIHYPERTENSIVE TREATMENT OF TYPE 2 DIABETES
EFFICACY AND SAFETY OF OPIOID AGONISTS IN THE TREATMENT OF
NEUROPATHIC PAIN
VITAMIN E AND DONEPEZIL (ARICEPT)
FOR MILD
COGNITIVE IMPAIRMENT
WEIGHT LOSS IN OVERWEIGHT ADULTS AND THE LONG-TERM RISK OF
HYPERTENSION
PROTON PUMP INHIBITOR TESTING TO DIAGNOSE GERD A Review Of
Likelihood Ratios
CALCIUM AND VITAMIN D INTAKE AND RISK OF INCIDENT PREMENSTRUAL
SYNDROME
JAMA, NEJM, BMJ, LANCET PUBLISHED
BY PRACTICAL POINTERS, INC
ARCHIVES INTERNAL
MEDICINE EDITED BY RICHARD T.
JAMES JR. MD
ANNALS INTERNAL MEDICINE
www.practicalpointers.org DAVIDSON
NC 28036 USA
This document is divided into two
parts:
1) The Highlights
section contains brief comments patterned after the “abstract” placed on
the first page of many studies reported in journals. Highlights condenses the content of studies, and allows a
quick review of pertinent points of each article.
The Editorial Comments are the editor’s assessments of the clinical practicality
of articles based on his long-term review of the current literature and his
20-year publication of Practical Pointers.
An Index containing all the Highlights is published twice a year. In
an evening or two, the reader can refresh memory of the entire content of
practical points abstracted from 6 major journals.
2) The main Abstracts
section is designed as a reference. It presents structured summaries of the
content of articles in much more detail.
I hope you will find Practical
Pointers interesting and helpful. The complete content of all issues for
the past 5 years can be accessed at www.practicalpointers.org
Richard T. James Jr, M.D.
Editor/Publisher.
HIGHLIGHTS AND EDITORIAL COMMENTS JUNE
2005
Reduced Incidence And Severity Of HZ And PHN.
6-1 A VACCINE TO PREVENT HERPES ZOSTER AND
POSTHERPETIC NEURALGIA IN OLDER ADULTS.
This study tested the hypothesis that
vaccination would decrease the incidence and severity of both HZ and PHN.
Over 38 000 subjects were randomized
to: 1) a subcutaneous injection of live, attenuated varicella-zoster vaccine, or
2) placebo. The potency of the live attenuated
A. Herpes zoster: (3 years) Vaccinated Placebo Absolute
difference NNT
Confirmed cases of acute HZ 315 642 1.7% 58
Overall incidence of HZ
per 100 person-years 0.54 1.11 0.57% 175
Median duration of pain (days) 21 24
Severity of illness 141 180 (area under the curve)
Burden of illness score 2.2 5.7
B. Postherpetic
neuralgia (3 years)
Confirmed cases 27 80 0.3% 333
Persistence of pain was shorter in the vaccinated group.
There was no evidence that the live
vaccine caused HZ.
Adverse effects were generally mild,
mainly due to local reactions.
We would expect more cases of HZ would be prevented as time progressed,
and as more individuals enter the ranks of the elderly. I asked myself—at my advanced age should I
take the vaccine? Having seen the devastating complications of zoster, I would be
more than willing to take it, even though the likelihood of prevention of HZ
over 3 years is only 1 in 58. .
Questions remain:
At what age should the vaccine be recommended?
How long is the boost in immunity protective?
Is it cost-effective enough for Medicare to cover costs?
Antibiotics Provided Little Advantage Compared With
No-Antibiotics.
6-2 INFORMATION LEAFLET AND ANTIBIOTIC
PRESCRIBING STRATEGIES FOR ACUTE LOWER RESPIRATORYINFECTION
Pharyngitis and acute bronchitis are the main
causes of excess antibiotic prescribing.
This pragmatic study assessed the
effectiveness of 3 different antibiotic strategies for acute bronchitis.
Randomized, controlled trial followed
over 800 patients presenting to primary care with acute uncomplicated LRI. Patients with findings suggestive of
pneumonia were excluded—new focal chest signs (focal crepitations or bronchial
breathing); and
systemic features (high fever, vomiting, severe diarrhea). Also
excluded patients with asthma, other
chronic or acute lung diseases, cardiovascular disease, or with previous pneumonia.
Randomized to: 1) no antibiotic prescribed [control group], 2) delayed prescription [to be picked up later],
or 3) immediately prescribed antibiotic. The antibiotic of choice was
amoxicillin 250 mg 3 times daily for 10 days, or, if allergic, erythromycin 250
mg 4 times a day for 10 days.
Compared with no antibiotics [control
group], the other strategies did not significantly alter cough duration: Delayed
prescription shortened duration by 0.75 days; immediate prescription by 0.11
days. Treatment group had no effect on
duration of other symptoms.
“Compared with immediate antibiotics,
a strategy of either no offer of antibiotics or a delayed prescription was
associated with little difference in duration or severity of symptoms.”
Overall, antibiotics probably do provide modest symptomatic relief. If a
benefit is present, it represents a shortening of only one day in a relatively
long history. “It is difficult to
justify widespread antibiotic prescribing for uncomplicated
lower respiratory infection on this basis, given the dangers of antibiotic
resistance.”
I was somewhat surprised at the duration of cough symptoms in this group
of patients—a mean total of 3 weeks. However, I believe most patients would experience
a gradual improvement over this period. We are admonished to consider pertussis
in patient with LRI when the cough lasts 3 weeks or more. I presume in
pertussis the cough continues unabated.
I believe advising patients that antibiotics may be associated with
serious adverse effects (eg, colitis) will do more to tilt them toward
accepting only symptomatic therapy than would advising them of the danger of
antibiotic resistance in the community.
I have had success in prescribing delayed prescriptions of patients with
uncomplicated lower respiratory infections. The great majority never fills the
prescription. This may be an acceptable means of satisfying a demanding
patient.
In the
The decision by primary care clinicians to prescribe or not prescribe, I
believe, will often depend on how “sick” the patient appears.
A Circumference Under 100 Cm Rules
Out Insulin Resistance And Hyper-Insulinemia.
6-3 USE OF WAIST CIRCUMFERENCE TO PREDICT
INSULIN RESISTANCE
This study assessed how effectively
different anthropometric markers used in clinical practice can predict insulin
sensitivity. The authors suggest abdominal circumference is the most powerful
independent predictor to rule out insulin resistance.
Determined height,
weight, and waist circumference (midway between lateral lower ribs and iliac
crest). Also
determined results from analyses of plasma for glucose, insulin, and lipid concentrations.
Used a homoeostasis index as a measure of insulin sensitivity [plasma glucose
(mol/L) X plasma
insulin (mU/L)/22.5]. A score of 4.0 and
greater was defined as insulin resistance.
Using 100 cm as a test, the authors determined
the sensitivity to diagnose insulin resistance was between 94-98%; and the
specificity was between 61-63%. The positive predictive values of the test were
61% for men and 42% for women. The negative predictive value of the test was
98% in men and 97% in women. A waist circumference under 100 cm was therefore a
strong independent predictor in ruling
out insulin resistance.
Waist circumference is a simple tool
to exclude insulin resistance. If the
patient has a circumference under 100 cm (40 inches),
he or she is very unlikely to have
insulin resistance and hyper-insulinemia. Circumferences above 100 cm may, or
may not, be related to insulin resistance.
I found this short article provocative. The results require confirmation.
Abdominal girth is an important risk factor for the metabolic syndrome and
cardiovascular disease.
6-4 SENSITIVITY, SPECIFICITY, AND PREDICTIVE
VALUES
The authors of the preceding article
calculated the sensitivity, specificity, and predictive values of the waist
circumference test.—the ability of the test to detect insulin resistance and
insulin sensitivity among healthy subjects by using 100 cm as a cut-off point. I
welcome opportunities to review these important statistical measures. I have
done so many times. I still have some difficulty in thinking them through and
calculating them accurately. I used the determinations in the article as an
example.
See the abstract.
“No Indication Of A Net Benefit.”
Current
“Prophylactic use of a potentially
toxic agent can be problematic, particularly in people in whom comorbidity and
polypharmacy are common.” In a prospective observational study in two large
This epidemiological modeling study
was conducted in a hypothetical population (10 000 men and 10 000 women)
selected from a reference population from a state in
Proportional benefit gained from
aspirin in prevention of MI and ischemic stroke vs excess hemorrhage from age 70-74 to age 100 or to death:
Benefit in preventing Men (n = 10 000) Women (n = 10 000)
Myocardial infarction - 389 - 321
Ischemic stroke - 19 - 35
Harm
Excess GI hemorrhage + 499 + 572
Excess hemorrhagic stroke + 76 + 54
When comparing net harms vs net benefits of aspirin, the effects
on length and quality of life were equivocal.
“Despite sound evidence for efficacy,
the temptation to blindly implement low-dose aspirin treatment for the primary prevention of cardiovascular
disease in elderly people must be resisted.” Benefits may be offset by harms.
I believe low-dose aspirin has an important place in primary prevention
of women at higher risk, and in secondary prevention of cardiovascular disease.
There is an important clinical downside related to universal prophylactic
aspirin therapy: suppose primary care
clinicians prescribe low-dose aspirin to 1000 women over 10 years. Three or 4
ischemic strokes might be prevented. But there would be no way of knowing which
individuals of the 1000 benefited. Conversely, a serious hemorrhagic event
occurring in 2 of the1000 patients would be self-evident. The clinician might
feel responsible, and the patient and family might blame the clinician for the
disaster.
I believe primary prevention with aspirin in women at average risk should
be avoided. Obviously, careful clinical judgment based on individual-patient
attributes is required.
“Our Most Important Finding Was The High Level Of
Antipsychotic Prescribing In NHs.”
6-6 THE
QUALITY OF ANTIPSYCHOTIC DRUG PRESCRIBING IN NURSING HOMES
Antipsychotic drug prescribing in
nursing homes (NHs) has been rising.
Federal statutes are in effect to
protect NH residents from receiving inappropriate antipsychotics. They may be
appropriately prescribed for delirium and dementia only if psychotic features
or dangerous behaviors are present. Guidelines also stipulate maximum daily
doses.
For residents with dementia,
behavioral assessments must also show evidence of verbal or physical aggression
or delusions or hallucinations.
Impaired memory, wandering,
restlessness, unsociability, uncooperativeness, and indifference to
surroundings are NOT indications.
Use of antipsychotic drugs in NHs was
widespread. Most atypicals were prescribed outside the prescribing guidelines with
doses, and for indications without strong clinical evidence of benefit. About 1
in 4 received doses exceeding recommended. About 2/3 of use was appropriate—dementia
with aggressive behavior; dementia with delusions; psychotic disorder. About
1/3 received the drugs inappropriately—impaired memory; depression without psychotic features; indifference to surroundings; insomnia; anxiety;
wandering; restlessness;
uncooperativeness; unsociability.
The study failed to detect positive
relationships between behavioral symptoms and antipsychotic therapy.
“This study raises questions about
the current uses of antipsychotics in NHs.”
These are powerful drugs. Elderly patients are subject to more adverse effects.
They require a lower dose because of impaired renal function and concomitant
illness. The PDR reiterates that schizophrenia is the only indication. There is
no mention of use in nursing homes. Few studies have concerned patients over
age 65.
I believe the most appropriate question to ask when contemplating use of
antipsychotics in NHs is…Am I prescribing this drug to benefit the patient, or
the nursing staff and the family? This can be a most difficult decision to
make. If they are prescribed, individual-
patient’s response must be carefully monitored.
When To Intervene? How To Intervene?
6-7 Thresholds For Normal
Blood Pressure And Serum Cholesterol.
In 2003, European guidelines
suggested a BP of above 140/90, and a cholesterol
above 5 mmol/L (193 mg/dL) as the appropriate thresholds for intervention. “The
bottom line is that the doctor is expected to inform the patient that these
measurements mean that he or she is at increased cardiovascular risk regardless
of the management proposed. In other
words, a disease label is to be attached to the patient.”
In
The potential benefits for treated
patients become less at lower risk levels. The number needed to treat is
increased. The rates of adverse effects (of drug treatment) remain the same.
Adverse effects tend to be under-reported and under-published.
Certainly, experts who developed these guidelines did not suggest that
all persons with BP and cholesterol levels above these cut-points should be
treated with drugs.
I believe however, that all should be treated with judicious advice about
changing in lifestyle. This will apply to almost all persons in the
I do not believe life-style advice will be interpreted as a labeling of
disease. There are few if any adverse effects of lifestyle changes.
Effectiveness is established. The benefit/harm-cost ratio is very low.
The task of educating patients about healthy lifestyles and getting them
to adopt them is daunting, and in the main unsuccessful. We should not be
deterred from trying. This includes primary care clinicians’ adopting a healthy
lifestyle themselves.
Who should be treated with drugs?—patients who are indeed at high risk.
The definition of “high risk” depends not only on the number or risk factors
present and their levels, but also on the individual patient’s assessment of
his own risk. Patients must be convinced of the benefits of drug therapy; must
understand that drug therapy is long-term, expensive, and carries risks of its
own.
No Evidence Of Superiority For Treatment With A
Calcium Channel-Blocker, Or An ACE Inhibitor Compared With A Thiazide-Type
Diuretic
The Antihypertensive and Lipid-lowering Treatment to prevent
Heart Attack Trial (ALLHAT)
This is one of a series of articles
reported by the ALLHAT group.
There was no evidence of superiority
for treatment with a calcium channel-blocker, or an ACE inhibitor compared with
a thiazide-type diuretic during first-step antihypertension therapy in DM, IFG,
or NG.
Most hypertensive patients with DM or IFG or impaired glucose tolerance,
I believe, would receive more than one antihypertension drug. Many clinicians
would use a combination of an ACE inhibitor and a diuretic..
Any combination should include a thiazide.
The abstract of this study is brief since I already
abstracted similar studies by the same ALLHAT group: A. JAMA December 18, 2002;
2981-97 presented the original ALLHAT study. (See Practical Pointers December
2002 [12-1] )
The study compared the same 3 drugs in similar patients with
hypertension and at least one additional risk factor (high-risk) . Conclusion: “Thiazide-type diuretics should be considered
first for pharmacological therapy in patients with hypertension. ” They are
unsurpassed in lowering BP, reducing clinical events, and in tolerability. They
are much less costly. Since many patients with hypertension will require more
than one drug to control their BP, it is reasonable to infer that a diuretic
should be included in all multidrug regimens.
B. JAMA April 6, 2005;
293: 1595-1608 (See
Practical Pointers April 2005 [4-2] ) “Thiazide-type diuretics
remain the drugs of first choice for initial therapy of hypertension in both
black and non-black hypertensive patients.”
C. Archives Int Med
See also:
NEJM December 30, 2004; 351: 2805-16 (Practical Pointers December 2004
[12-2] ) “Association between
Cardiovascular Outcomes and Antihypertensive Treatment in Older Women”
Conclusion: Monotherapy
with diuretics was equally or more effective than other monotherapies. The
combination of diuretics + beta-blockers was superior to, or equally effective
as, other combinations.
Likely To Produce Clinically Important Pain Relief.
Effective pain relief in these
patients is difficult to achieve. Use of opioids is controversial. This is in
part because studies have been small, have yielded equivocal results, and have
not established long-term efficacy and safety. There have been concerns about
adverse effects: potential for abuse and
addiction, hormonal abnormalities, dysfunction of the immune system, and
paradoxical hyperalgesia.
This systematic review assessed the
efficacy and safety of opioids for treatment of NP.
Opioid treatment for 1 to 8 weeks had a
beneficial effect over placebo for spontaneous neuropathic pain. The magnitude
of this opioid effect was nearly a 14-point difference in pain intensity at
study end compared with placebo. Is an
average decline of 14 points on a 100-point scale meaningful to patients? The
mean initial pain intensity ranged from 46 to 69. A 14-point difference
corresponds to a 20% to 30% reduction in pain.
The trial did not address issues of
addiction. It is reasonable to assume that the studies did not include
individuals who might be potential abusers.
The most common adverse effects were
nausea, constipation, drowsiness, vomiting, and dizziness.
(NNT to harm one patient = 4 to 7.)
I believe primary care clinicians underuse opioids for patients with
non-cancer pain. Fears of addiction have been overemphasized.
Donepezil May Delay Clinical
Progression To Alzheimer’s Disease
6-10 VITAMIN E AND DONEPEZIL (ARICEPT) FOR THE TREATMENT OF MILD
COGNITIVE IMPAIRMENT
Amnestic (memory loss) mild cognitive impairment (MCI)
represents a transitional state between the cognitive changes of normal aging
and the earliest clinical features of Alzheimer’s disease (AD). Amnestic MCI refers to the
subtype that has a primary memory component, either alone or in conjunction
with other cognitive-domain impairments, of insufficient severity to constitute
dementia. About 80% of those who meet the criteria for MCI will have AD within
6 years.
MCI is a transition state between
normal aging and dementia (for Alzheimer’s disease in particular), one in which
cognitive deficits are present, but function preserved. In clinical settings,
the term is often used to describe patients who present with memory loss, but
do not have dementia. Even when defined carefully, MCI is a heterogeneous
category that includes some persons with memory changes of normal aging, some
with non-progressive cognitive defects, some with prodromal AD, and some with
prodromal forms of other neurodegenerative dementias.
This study was designed to determine
if vitamin E or the cholinesterase inhibitor donepezil could delay the clinical
diagnosis of AD in patients with MCI.
Vitamin E had no effect at any time.
For donepezil
. . . “The observed relative reduction in the risk of progression of 56% at one
year and 36% at two years in the entire cohort is likely to be clinically
significant.”
“Although our findings do not provide
support for a clear recommendation for the use of donepezil in persons with
mild cognitive impairment, they could prompt a discussion between the clinician
and the patient about this possibility.”
Symptoms of memory loss in older
persons should be taken seriously. They may represent the beginning of AD. This
may be an important clinical measure once more effective
treatments become available.
The important question is . . . What
are the cognitive changes of normal aging?
I believe some degree of memory impairment is almost universal among
individuals over age 80. It usually begins by forgetting names, and recalling
them minutes or hours later ( “senior moments”). The
spectrum of memory impairment is wide. The definition of amnestic MCI is not
settled. At what point does it predict development of AD? The criteria for
diagnosis of amnestic MCI in the study included patients with difficulties
greater than temporarily forgetting names.
This study may foretell important developments in drug therapy which may
delay the onset of disabling dementia. The spectrum of forgetfulness of old age
is very broad. When should intervention be considered? Some elderly patients may well accept early
intervention. A delay of one to two years represents a large proportion of
remaining quality-life. Patients may be willing to accept some adverse effects
of drugs to gain a few years free of dementia of AD. (Note that
anticholinergics do not benefit vascular dementia.)
Others may wish to wait until adverse effects on daily living become more
evident.
I do not believe memory defects inevitably progress to AD. Keeping
mentally and physically active, continuing a healthy diet, retaining active
family and social connections, and controlling risk factors for cardiovascular
disease will delay or prevent development of dementia in many individuals.
In Modestly Overweight Persons, Reduction In Weight May Lower
Risk Of Developing Hypertension.
6-11 WEIGHT LOSS IN
OVERWEIGHT ADULTS AND THE LONG-TERM RISK OF HYPERTENSION: The Framingham Study
Obesity is associated with higher
levels of insulin resistance, hyperinsulinemia, rises in cardiac output,
increases in cholesterol and triglycerides, and increased sympathetic nervous
system activity. Most of these changes have been associated with increases in
BP. “In recent years, there has been a great deal of focus on the roles of
hyperinsulinemia and insulin resistance in the development of hypertension.”
The goal of this study was to
estimate the effects of both the amount on weight loss and the persistence of
weight loss on the risk of incident hypertension among already obese adults. (Primary prevention.)
After multiple adjustments, weight
loss of 6.8 kg (18 pounds) or more led to a 28% reduction in risk of developing
long-term hypertension in younger subjects (mean age 27) , and a 37% reduction
in older subjects (mean age 52).
If the weight loss was sustained over
the years, the risks of developing hypertension were reduced by 22% and
26%.
“The results of this study suggest
that at least 15% of the cases of hypertension in overweight middle-aged adults
and 22% of the cases occurring in overweight older adults could be prevented by
a modest amount of sustained weight loss.”
Overweight + hyperinsulinism + dyslipidemia +
hypertension = a common and deadly combination
Treatment Reduced Serious Perinatal
Morbidity In Infants And May Improve The Woman’s
Health-Related Quality Of Life.
6-12 GESTATIONAL DIABETES MELLITUS; Effect Of Treatment
On Pregnancy Outcomes.
Gestational diabetes mellitus (GDM) occurs in up to 9% of all
pregnancies. It is associated with substantial maternal and perinatal
complications. Neonatal complications include macrosomia, shoulder dystocia,
birth injuries, bone fractures, nerve palsies, and hypoglycemia. Long-term
adverse health outcomes among infants born to mothers with GDM include
sustained glucose intolerance, subsequent obesity, and impaired intellectual achievement.
This study asked . . . Does screening
and treatment for GDM reduce these risks?
This randomized trial enrolled 1000
women who were between 16 and 30 weeks pregnant. Randomized to: 1) An intervention group received expert
diabetes care including education, self-monitoring blood glucose, and adjusted
insulin therapy, and 2) A usual care group.
Serious perinatal
complications in infants were significantly lower in the intervention group (1%
vs 4%). The NNT to prevent one serious outcome in infants = 34. Birth weights were lower in the intervention
group (less likely to have macrosomia). No
difference in rate of hypoglycemia requiring intravenous glucose.
Women in the intervention group
gained less weight and had less risk for preeclampsia. At 3-months postpartum,
women had lower rates of depression and higher scores on quality-of-life. Rates
of caesarean deliveries were similar.
Impaired glucose tolerance and diabetes are important risk factors at the
time of conception. Primary care clinicians can serve their young adult female
patients by advising them of the risks of glucose intolerance (and excessive
weight) before and at the time of conception.
The Test Could Be Used As An Initial
Approach To Diagnosis.
Gastro esophageal reflux disease (GERD) is the most common cause of
non-cardiac chest pain (NCCP). Patients
with NCCP are often treated empirically and successfully with proton pump
inhibitors.
This study asked.
. .Can proton pump inhibitors ( a PPI test) be used as a diagnostic test?
Results of the PPI test:
GERD present GERD absent
Positive test (> 50% relief) 80% (true positive)* 26% (false positive)
Negative test (< 50% relief) 20% (false negative) 74% (true negative test)**
(* sensitivity of the PPI test = true + % = 80%; **
specificity of the PPI test = true negative % = 74%)
Results of the placebo test:
Positive test (> 50% relief) 19% (true positive)*** 23% (false positive)
Negative test (< 50% relief) 81% (false negative) 77% (true negative test)****
(*** sensitivity of placebo test
=19%; **** specificity of placebo test = 77%)
Thus 80% responded favorably to PPI vs 19% to placebo.
Treatment with PPIs
and placebo showed similar effects (26% and 23%) on improving NCCP symptoms
in patients without GERD, indicating a possible placebo effect.
The use of PPI as a diagnostic test
for detecting GERD in patients with NCCP has an “acceptable” sensitivity and
specificity and could be used as an initial approach by primary care physicians
to detect GERD in selected patients with NCCP.
“Acceptability of the test would be more meaningfully determined by
calculating pre-test probability., likelihood ratios,
and post-test probability. See the full abstract.
Regardless of the modest diagnostic help given by a PPI test, I believe,
in practice, the test is used extensively by primary care clinicians and their
patients.
May Reduce Risk Of Development Of
PMS.
6-14 CALCIUM AND VITAMIN D INTAKE AND RISK OF
INCIDENT PREMENSTRUAL SYNDROME
Several studies have suggested that
calcium and vitamin D levels are lower in women with PMS, and that calcium
supplementation may prevent the initial development of PMS.
This case-control study was nested
within the large prospective Nurses’ Health Study. Participants were a subset
of women age 27 to 44 (mean =
35). All were free of PMS at baseline (1991). Cases: 1057 women who developed PMS over a 10-year
follow-up. Controls: 1968 women who
reported no diagnosis of PMS and no, or minimal, menstrual symptoms.
Determined dietary
and supplemental intakes of calcium and vitamin D by periodic questionnaires.
Women in the highest quintile of total
vitamin D intake (median of 706 IU) had a relative risk of new-onset PMS of
0.59 compared with those in the lowest quintile (median of 112 IU). Benefit was
associated with vitamin D from food. Supplemental vitamin D did not seem to be associated
with risk.
Similar benefit was associated with
calcium intake from food.
I abstracted this article because its conclusions are
provocative—certainly not definitive. It raises more questions: Why did the benefit not extend to
supplements? Is there a reasonable
biological mechanism for the action of calcium and vitamin D? Why no benefit
from whole milk? At a more practical
level—could diet be beneficial in treatment as well as prevention?
I will watch for more developments.
Hope For Reducing The Prevalence Of
This World-Wide Scourge.
6-15 BASIC SCIENCE GUIDELINES DESIGN OF NEW TB
VACCINE CANDIDATES
Several new vaccines which improve
immune response are under investigation. They may be helpful in primary
prevention of infection as well as boosting immunity in those with latent
infection.
See the abstract.
(The
entire June 8 2005 issue of JAMA is devoted to tuberculosis.)
ABSTRACTS JUNE 2005
Reduced Incidence And Severity Of HZ And PHN.
6-1 A
VACCINE TO PREVENT HERPES ZOSTER AND POSTHERPETIC NEURALGIA IN OLDER ADULTS.
Cell-mediated immunity declines with
age. This increases likelihood of reactivation of the latent varicella-zoster
virus within the sensory ganglia, causing herpes zoster (HZ). Complications of HZ
occur in about 50% of elderly patients, most commonly postherpetic neuralgia (PHN).
The pain of PHN can be prolonged and
disabling. It can diminish the patient’s quality of life and ability to
function to a degree comparable to that of diseases such as congestive heart
failure, myocardial infarction, type 2 diabetes, and
major depression.
Antiviral therapy reduces the
severity and duration of the acute phase of HZ, but does not prevent PHN.
Recurrences of HZ are uncommon among
immunocompetent persons because an episode of acute HZ boosts immunity,
effectively “immunizing” against a subsequent attack.
Vaccines can elicit a significant
increase in cell-mediated immunity to HZ in immunocompetent older adults.
This study tested the hypothesis that
vaccination would decrease the incidence and severity of both HZ and PHN.
Conclusion: The vaccine markedly reduced incidence and
severity of HZ and PHN.
STUDY
1. A randomized,
double-blind placebo-controlled trial enrolled over 38 000 adults. All were
over age 60 (46% over age 70).
2.
Randomized to: 1) a subcutaneous injection of live, attenuated varicella-zoster
vaccine, or 2) placebo. The potency of the live attenuated
3. Determined incidence,
severity and duration of subsequent acute HZ, and incidence of PHN.
RESULTS
1. Over 95% of subjects completed the 3-year study.
2. Outcome:
A. Herpes zoster: (3y) Vaccinated Placebo Absolute
difference NNT
Confirmed cases of acute HZ 315 642 1.7% 58
Overall incidence of HZ
per 100 person-years 0.54
1.11 0.57% 175
Median duration of pain (d) 21 24
Severity of illness 141
180 (area under the curve)
Burden of illness score 2.2 5.7
B. Postherpetic neuralgia (3y)
Confirmed cases 27 80 0.3% 333
Persistence of pain was
shorter in the vaccinated group.
3. During the first 42
days after vaccination, 7 cases of HZ occurred in the vaccine group vs 24 in
the placebo group. (Apparently the boost in immunity occurs quickly.)
4. The results of PCR
testing were positive for wild-type varicella-zoster virus DNA in over 93% of
cases. The vaccine virus DNA was not detected in any case. (Ie, the live
vaccine does not cause HZ.)
6. Adverse events:
Serious adverse
events—number and types of were similar in both groups.
Local reactions
(especially erythema and tenderness) were more common in the vaccine group.
They were usually mild.
Hospitalizations were
similar and not considered related to the vaccine. No vaccine recipient developed fever over
38.30
DISCUSSION
1. An estimated 1 million
cases of HZ occur in the
2. In older subjects in
the study, the benefit of the vaccine in reducing incidence of HZ was less, but
the effect on reducing severity of the illness was greater.
3. The potency of the
vaccine was much greater than the vaccine given to children. “We do not recommend
the use of the current varicella vaccine in an attempt to protect against
herpes zoster and postherpetic neuralgia.”
CONCLUSION
The vaccine markedly reduced
morbidity from acute HZ, and PHN.
NEJM June 2, 2005; 352:
2271-84 Original investigation by
the Shingles Prevention Study Group, first author M N Oxman, VA San Diego
Health-care System, CA.
An editorial in this issue of NEJM
(pp 2344-46) by Donald H Gilden, comments:
Should vaccine be recommended for all
VZV-seropositive middle-aged adults who have not had zoster? The author
suggests that grown-ups should welcome the vaccine. “We may need it more than
children do.” He cites 2 considerations:
1) What is the future risk of zoster
among adults who were vaccinated for chickenpox in childhood? At present, most
elderly people have not been vaccinated. By 2047, most middle-aged Americans
will have received chickenpox vaccine. They have not had chickenpox. Like the wild-type virus, the live
2) Cost-effectiveness: This depends on price. It may be that the adult vaccine, given its
greater potency, will be more expensive than the childhood vaccine.
Nevertheless, the zoster vaccine appears to be highly cost-effective even
assuming a cost of $500.
================================================================================
“No Difference in
Symptom Relief”
6-2 INFORMATION LEAFLET AND ANTIBIOTIC
PRESCRIBING STRATEGIES FOR ACUTE
Pharyngitis and acute bronchitis are the main
causes of excess antibiotic prescribing. Costs each year exceed $700 million. A
consensus has been made for limiting use of antibiotics in lower respiratory
infections. (LRI). But recent systematic reviews have come to
diverse conclusions about the effectiveness of antibiotics. The most recent
Cochrane review confirms a moderate benefit of antibiotics on the course of the
illness, but called for more evidence. Reviews have concerned relatively small
numbers of patients.
Strategies to treat upper respiratory which do not include
initial antibiotics—either no antibiotics or delayed antibiotics—are effective
in up to 90% of cases, result in acceptable symptom control, are satisfactory
to the patient, and can reduce reconsultation by up to 40%.
The debate about use of antibiotics for
lower respiratory infections continues.
This pragmatic study assessed the
effectiveness of 3 different antibiotic strategies, and the effectiveness of an
information leaflet given to patients compared with brief verbal information
alone.
Conclusion: There was no difference in symptom resolution
between immediate prescription of antibiotic, no prescription for antibiotic,
and delayed prescription. The information leaflet was of little help.
STUDY
1. Randomized, controlled trial followed over
800 patients presenting to primary care with acute uncomplicated
LRI. Patients with findings suggestive of
pneumonia were excluded—new focal chest signs (focal crepitations
or bronchial breathing);
and systemic features (high fever, vomiting, severe diarrhea). Also excluded patients with asthma, other chronic or acute lung
diseases, cardiovascular disease, or with previous pneumonia.
2. The patients included
17% under age 16 and 17% over age 60. (mean age 39). They
were moderately ill. The majority had fever, sore throat, and coryza. Many were
producing dark green sputum. Some had coarse crepetitations
and wheeze.
3. The mean duration of
cough before the first consultation was 9 days.
4. Randomized to: 1) no antibiotic prescribed [control group], 2) delayed prescription [to be picked up later],
or 3) immediately prescribed antibiotic. The antibiotic of choice was amoxicillin
250 mg 3 times daily for 10 days, or, if allergic, erythromycin 250 mg 4 times
a day for 10 days.
5. The delayed
prescription was left in a box in the reception room of the office to be picked
up at any time the patients wished.
6. Patients were also
randomized to receive, or not receive, an information leaflet describing the
natural history of acute LRI. (I omit
this data, since it provided little benefit compared with a brief oral
consultation. RTJ)
7. Patients were asked to
record their temperatures. They also were asked to keep a diary and record use
of antipyretics, and severity of 6 symptoms—cough,
dyspnea, sputum production, well-being, sleep disturbance, and activity
disturbance.
RESULTS
1. After the
consultation, cough rated as at least a “slight problem” lasted for a mean of
12 days (25% over 17 days).
2. Compared with no
antibiotics [control group], the other strategies did not significantly alter
cough duration: delayed prescription shortened duration by 0.75 days; immediate
prescription by 0.11 days. Treatment
group had no effect on duration of other symptoms.
3. Immediate
Delayed Control (none prescribed)
Use of antibiotics: 96%; 20%; 16%.
Patients “very satisfied” 86%; 77%, 72%.
Believed antibiotics to be effective 75% 40% 47%
Re-attendance within 1 month 11% 12% 19%
(Note
that relatively few of the delayed group actually had prescriptions filled.)
4. Adverse events; one patient (of
212) in the no antibiotic group developed pneumonia. He was hospitalized and
treated with antibiotics. He recovered fully.
DISCUSION
1. There is no widely
agreed definition of lower respiratory infection. In practice, most patients
have cough with sputum.
2. “Our study confirms
the long history of lower respiratory infection. Patients need to be warned that they will on
average have an illness lasting 3 weeks in total with10 days of symptoms before
the physician visit and 12 days after the physician visit.”
3. “Compared with
immediate antibiotics, a strategy of either no offer of antibiotics or a
delayed prescription was associated with little difference in duration or
severity of symptoms.”
Overall, antibiotics probably do provide modest symptomatic relief. If a
benefit is present, it represents a shortening of only one day in a relatively
long history. “It is difficult to
justify widespread antibiotic prescribing for uncomplicated lower respiratory
infection on this basis, given the dangers of antibiotic resistance.”
4. A high percentage of patients receiving
no antibiotics or delayed prescription for antibiotics were satisfied with their
treatment.
5. The practice of no
offer of antibiotics and delayed prescription for antibiotics is likely to
reduce use of antibiotics.
CONCLUSION
For patients with LRI, not
prescribing antibiotics or offering a delayed prescription (compared with
immediate prescription) was associated with little difference in symptom
resolution.
JAMA June 22/29, 2005; 293:
3029-35 Original investigation, first author
Paul Little,
A Circumference Under 100 Cm Rules Out Insulin Resistance And
Hyper-Insulinemia.
6-3 USE OF
WAIST CIRCUMFERENCE TO PREDICT INSULIN RESISTANCE
Insulin resistance is an important component
of the metabolic syndrome. No easy clinical test exists to determine insulin
resistance in an individual.
This study assessed how effectively
different anthropometric markers used in clinical practice can predict insulin
sensitivity. The investigators analyzed a sample of 2746 healthy volunteers
(798 male) from retrospectively collected data. Ages ranged from 18 to 72; body
mass indexes from 18 to 60; and waist circumferences from 65 cm to 150 cm.
Determined height,
weight, and waist circumference (midway between lateral lower ribs and iliac
crest). Also
determined results from analyses of plasma for glucose, insulin, and lipid concentrations.
Used a homoeostasis index as a measure of insulin sensitivity [plasma glucose
(mol/L) X plasma
insulin (mU/L)/22.5]. A score of 4.0 and
greater was defined as insulin resistance.
Assessed predictive power of 5
variables: waist circumference; plasma triglycerides; systolic BP; HDL-cholesterol; and body mass index.
Set the optimal abdominal
circumference cut-point for detecting insulin resistance at 100 cm (40 inches)
for both men and women. Using 100 cm as a test, the authors determined the
sensitivity to diagnose insulin resistance was between 94-98%; and the
specificity was between 61-63%. The positive predictive values of the test were
61% for men and 42% for women. The negative predictive value of the test was
98% in men and 97% in women. A waist circumference under 100 cm was therefore
very predictive in ruling out insulin
resistance. (These figures depend on the prevalence of insulin resistance in
the actual sample.)
COMMENT
1. Some studies report that
the prevalence of the metabolic syndrome is similar in both sexes.
2. “A waist circumference
under 100 excluded individuals of both sexes from the risk of being insulin
resistant.”
3. At a cut point of 88
cm (currently recommended for women) the specificity drops markedly. (Too many false positives for insulin resistance.) “Abdominal obesity is overestimated in
women.”
CONCLUSION
Waist circumference is a simple tool
to exclude insulin resistance. If the
patient has a circumference under 100 cm, he or she is
very unlikely to have insulin resistance and hyper-insulinemia. Circumferences
above 100 cm (40 inches) may, or may not, be related to insulin resistance.
BMJ June 11, 2005: 330: 1363-64 Original investigation, first author Hans
Wahrenberg, Karolinska Institute,
6-4 SENSITIVITY, SPECIFICITY, AND PREDICTIVE
VALUES: A Review By The Editor
The authors of the preceding article
calculated the sensitivity, specificity, and predictive values of the waist
circumference test.—the ability of the test to detect insulin resistance and
insulin sensitivity among healthy subjects by using 100 cm as a cut-off point. I
welcome opportunities to review these important statistical measures. I have
done so many times. I still have some difficulty in thinking them through and
calculating them accurately. I used the determinations in the article as an
example.
SENSITIVITY
Start by considering only subjects who have the disease, in
this case insulin resistance.
Sensitivity of the 100 cm test for
men:
Sensitivity of the test =
% of subjects who have the disease (insulin resistance) who have a positive
test (waist 100 cm and above)—ie, the true positive %.
Insulin resistance present (n = 284)
(The test) (disease present)
Waist 100 cm and above (true positive
test) 277
Waist under 100 cm (negative test) 7
Total 284
The sensitivity of the test for men =
277/284 = 98% (the true positive %)
By the same calculations the
sensitivity of the test in women = 63%.
SPECIFICITY
Start by considering only subjects who do not have the disease—are not insulin
resistant (are insulin sensitive)
Specificity of the 100 cm test for
men:
Specificity of the test =
% of subjects who do not have the disease (are insulin sensitive) who have a
negative test (waist under 100 cm—the true negative %).
Insulin sensitive (n = 469)
(The test) (disease absent)
Waist 100 cm and above (false positive test) 176
Waist under 100 cm (true negative
test) 293
Total 469
Specificity of the test for men =true
negative % = 293/469 = 63%
By the same calculations the specificity
of the test in women = 97%
PREDICTIVE VALUE OF POSITIVE TESTS (POSITIVE PREDICTIVE
VALUE)
Start by considering only subjects in
the cohort who have a positive test.
Among men who have positive tests
(both true positive and false positive) what percentage are true positives?
In this cohort of men: Positive tests
True positive tests 277 The predictive value of a
positive test = true positive/total
False positive tests 176 positive = 277/453 = 61%. (Not
discriminating)
Total tests 453
PREDICTIVE VALUE OF NEGATIVE TESTS (NEGATIVE PREDICTIVE
VALUE)
Start by considering only subjects in the cohort who have a
negative test.
In this cadre of men Negative tests
True negative tests 293 The predictive
value of a negative test = true negative/total
False negative tests 7 negative = 293/300 = 98%
Total tests 300 (Very
discriminating)
For a man with a waist
circumference below 100 cm, the likelihood that he had insulin resistance was
very low. (98%)
For women, negative predictive value
was 97%. If a woman had a waist circumference less than 100 cm, the likelihood
that she had insulin resistance was also very low.
Practical Pointers for Primary Care June 2005 Comments by the editor
“No Indication Of A Net Benefit.”
6-5 EPIDEMIOLOGICAL MODELLING OF ROUTINE USE OF
LOW-DOSE ASPIRIN FOR THE PRIMARY PREVENTION OF CORONARY HEART DISEASE AND
STROKE IN THOSE AGE > 70
Current
“Prophylactic use of a potentially
toxic agent can be problematic, particularly in people in whom comorbidity and
polypharmacy are common.” In a prospective observational study in two large
Most primary prevention trials are
conducted in middle-aged people, not in the elderly.
This study investigated the benefit
of routine use of low-dose aspirin in people over age 70 who
had no history of overt cardiovascular disease.
Conclusion; Any benefits are likely offset by
adverse effects.
STUDY
1. This epidemiological
modeling study was conducted in a hypothetical population (10 000 men and 10
000 women) selected from a reference population from a state in
2. Main outcome measure =
first ever myocardial infarction (MI),
stroke, or gastrointestinal hemorrhage.
3. Calculated
health-adjusted years of life lived related to use of low-dose aspirin from age
70-74 until death or age 100.
RESULTS
1. Proportional benefit gained from aspirin in prevention of
MI and ischemic stroke vs excess
hemorrhage:
Benefit in preventing Men (n = 10 000) Women (n = 10 000)
Myocardial infarction - 389 - 321
Ischemic stroke - 19 - 35
Harm
Excess GI hemorrhage + 499 + 572
Excess hemorrhagic stroke + 76 + 54
2. When comparing net harms vs net benefits of aspirin, the effects
on length and quality of life were equivocal.
DISCUSSION
1. The model suggests
that benefit gained from routinely prescribing low-dose aspirin to patients aged
70 and above in terms of preventing first ever cardiovascular events would be
offset by a greater occurrence of gastrointestinal and intracerebral bleeding.
“On balance, there was no indication of a net benefit.” However, because of the
uncertainty in the assumptions, the balance of harm and benefit could tip in
either way.
2. Consideration needs to
be given to possible adverse effects, especially in special risk groups such as
elderly people.
3. Due to the wide
confidence intervals determined by the study, the overall outcome could be
beneficial or adverse.
CONCLUSION
“Despite sound evidence for efficacy,
the temptation to blindly implement low-dose aspirin treatment for the primary prevention of cardiovascular
disease in elderly people must be resisted.” Benefits may be offset by harms.
BMJ June 4, 2005; 330: 1306-08 “Primary Care”, original investigation, first author
Mark R Nelson,
An editorial in Annals Int Med June
7, 2005, first author Cynthia Mulrow, Deputy Editor, comments on the recently
published study (NEJM 2005; 352:
1293-304) of aspirin
in primary prevention in a large group of healthy women over age 45 who were at
average risk:
Effect of low-dose aspirin over 10
years:
All-cause mortality: little or no
effect
Ischemic strokes prevented: 3 to 4
Myocardial infarction: little or no
effect
Hemorrhagic strokes caused: 0 to 1
Major gastrointestinal bleeding: 1
There was some evidence that women
over age 65 benefited more, but they also are at risk for more serious adverse
effects.)
Reviewing a landmark study 16 years on:
FINAL REPORT ON THE
ASPIRIN COMPONENT OF THE ONGOING PHYSICIANS’ HEALTH STUDY NEJM
This landmark primary prevention
study led to use of low-dose aspirin by millions of men in the
Over 22 000 male physicians entered a
double-blind, placebo-controlled 5-year trial:
1) 325 mg aspirin every other day vs 2) placebo. The benefit of aspirin
was significant—a 44% reduction in risk of myocardial infarction (MI). Benefit
was evident only for men over age 50.
In absolute terms, over 100 000
person-years of aspirin use, 183 myocardial infarcts were prevented
(~ 2/1000 per year). When non-fatal MI, non-fatal stroke,
and cardiovascular deaths were combined, the reduction in risk in the aspirin
group was lowered to 18%. (NNT for one year to prevent one event = 2000)
Total stroke and hemorrhagic stroke
were non-significantly increased in the aspirin group. Cardiovascular mortality
was unchanged. There was a trend toward greater benefit in individuals with
risk factors—elevated cholesterol, family history of CVD, diabetes, smokers,
and history of hypertension.
The trial did not include females and
the very elderly.
I believe many primary care physicians extrapolated the results and
prescribed prophylactic aspirin to women.
Indicated Only If Psychotic Features Or Dangerous Behaviors
Are Present.
6-6 THE QUALITY OF
ANTIPSYCHOTIC DRUG PRESCRIBING IN NURSING HOMES
Antipsychotic drug prescribing in
nursing homes (NHs) has been rising.
This is attributed to the availability of second-generation agents.1 These
“atypical” agents have replaced the older conventional agents, and have
transformed therapeutic applications. In
practice, use has been expanded to indications outside those approved by the
FDA. The influence of atypicals in NHs is especially remarkable because antipsychotic
drug use must adhere to prescribing guidelines of appropriateness. This limits off-label use.
There are concerns about the quality
of care, especially when discordant with prescribing guidelines. Most atypicals
have been approved because of demonstrated efficacy for schizophrenia. Yet,
they are increasingly being prescribed for other reasons, based on less
evidence. In 1986, the
In NHs, atypicals are prescribed
mainly for behavioral and psychological symptoms associated with dementia, even
though the clinical findings of benefit are equivocal. Safety is also under
review. Serious adverse events have been associated with use—falls, somnolence,
and abnormal gait. (And even deaths.)
Federal statutes are in effect to
protect NH residents from receiving inappropriate antipsychotics. They may be
appropriately prescribed for delirium and dementia only if psychotic features
or dangerous behaviors are present. Guidelines also stipulate maximum daily
doses.
For residents with dementia,
behavioral assessments must also show evidence of verbal or physical aggression
or delusions or hallucinations.
Impaired memory, wandering,
restlessness, unsociability, uncooperativeness, and indifference to
surroundings are NOT indications.
This study assessed prevalence of
antipsychotic use in nursing homes, rates of adherence to prescribing
guidelines, and resultant changes in behavior in recipients.
Conclusion: Use of anti-psychotic drugs in NHs was widespread.
Most atypicals were prescribed outside the prescribing guidelines, with doses,
and for indications without strong clinical evidence of benefit. The study
failed to detect positive relationships between behavioral symptoms and
antipsychotic therapy.
STUDY
1. Retrospective analysis
using nationally representative data from Medicare assessed prevalence of use
of anti-psychotics, rates of adherence to guidelines, and resultant changes in
behavioral symptoms.
RESULTS
1. An estimated 45% of
Medicare beneficiaries in NHs had indications appropriate for antipsychotic
therapy. (This far exceeds my experience.
RTJ) Behavioral problems, especially
physical and verbal aggression, were more common among recipients relative to
non-users.
2. An estimated 28% of
residents of NHs received at least one antipsychotic during the study period.
This approximates over 650 000 patients; 20% of residents received atypicals.
Spending for antipsychotics has increased substantially.
3. Many residents
received therapy outside the prescribing guidelines. One in 4 had no
appropriate indication. About 1 in 4 received doses exceeding recommended.
4. About 2/3 of use was
appropriate: dementia with aggressive
behavior; dementia with delusions; psychotic disorder.
5. About 1/3 received the
drugs inappropriately: impaired
memory; depression without psychotic
features; indifference to surroundings;
insomnia; anxiety; wandering; restlessness; uncooperativeness; unsociability.
6. Nearly 40% of the
study population using antipsychotics regularly resisted taking medication or
eating meals, made disruptive noises, disrobed in public, or threw food.
7. About 5% of recipients
were considered improved;
85% no change; 10% deteriorated. There was no difference in effect between
those receiving appropriate dosing for appropriate indications, and those receiving
an excessive dose for inappropriate indications
DISCUSSION
1. “Our most important
finding was the high level of antipsychotic prescribing in NHs.”
2. About half of the
Medicare NH residents who received antipsychotics took doses exceeding maximum
levels, received duplicative therapy, or had inappropriate indications.
3. Most out-of-guideline prescribing was for
memory problems, non-aggressive behavior, or depression without psychotic
features.
4. Doses prescribed often
exceeded guidelines.
5. “This study raises
questions about the current uses of antipsychotics in NHs.”
CONCLUSION
Use of antipsychotics
in NHs is widespread. Most atypicals
were prescribed outside prescribing guidelines, and used higher doses for
indications for which there was no strong clinical evidence of benefit.
Failure to detect positive
relationships between behavioral symptoms and antipsychotic therapy raises
questions about appropriateness of prescribing.
Archives Int Med
June 13, 2005; 165: 1280-85
Original investigation, first author Becky A Briesacher,
1 Clozapine
Risperidone Olanzapine
Quatrain Ziprasidone Aripiprazole
Older agents included haloperidol (Haldol) and chlorpromazine (Thorazine).
When To Intervene? How To Intervene?
6-7 Thresholds For
What is “normal” BP?.
What is “normal” cholesterol? There is disagreement. In 1999 over 800 doctors wrote the director
general of the WHO outlining fears that their new hypertension guidelines would
result in increased use of antihypertension drugs at great expense, and for
little benefit.
The simplistic linear structuring of
many research questions, and the extrapolation of research results produce
guidelines that make many doctors feel uneasy about the high proportion of
patients who are being labeled as sick.
Primary care clinicians are aware of
the adverse effects of undue medicalization. They tend to question the external
validity (the application of trial results to individual patients seen in
practice) of randomized controlled trials under experimental conditions. They
also have to consider the costs of intervening to alter risk profiles of large
numbers of healthy people. “The uneasiness is about primary prevention being
conceived increasingly as a strategy implying individual risk identification
and questionable labeling of disease.”
In 2003, European guidelines
suggested a BP of above 140/90, and a cholesterol above
5mmol/L (193 mg/dL) as the appropriate thresholds for intervention (lifestyle
and drug treatment). “The bottom line is
that the doctor is expected to inform the patient that these measurements mean
that he or she is at increased cardiovascular risk.” “A disease label is to be attached to the
patient.”
In
Issues to be considered:
1) The potential benefits
for treated patients become less at lower risk levels. The number needed to
treat to benefit is increased. The rates of adverse effects (of drug treatment)
remain the same. Adverse effects tend to be under-reported and under-published.
2) Evidence for the long-term effectiveness of treatment is lacking. Data from short-term studies are being extrapolated over the whole of the remaining lifespan.
3) We have limited evidence on the effects of preventive drug treatment when several drugs are used to treat different risk factors simultaneously.
4) We have far too little understanding of the psychological impact and the wider health consequences of being labeled at risk.
5) Overall costs to society may be tremendous.
BMJ
June 25, 2005; 330: 1461-62
Editorial, first author Steiner Westin,
No Evidence Of Superiority For A Calcium
Channel-Blocker, Or An ACE Inhibitor Compared With A Thiazide-Type Diuretic as
Initial Therapy
6-8 CLINICAL OUTCOMES IN ANTIHYPERTENSIVE
TREATMENT OF TYPE 2 DIABETES, IMPAIRED FASTING GLUCOSE CONCENTRATION, AND
NORMOGLYCEMIA
The Antihypertensive and Lipid-lowering Treatment to prevent
Heart Attack Trial (ALLHAT)
This sub-set of the ALLHAT trial
determined whether treatment with a calcium-blocker, or an
angiotensin-converting enzyme inhibitor would decrease clinical complications as
compared with a thiazide-type diuretic in patients with type 2
diabetes (DM), impaired fasting
glucose (IFG), and
normoglycemia (NG). The double-blind
randomized, controlled trial entered over 31 000 adults with hypertension, all
over age 55. All had at least one additional risk factor for coronary heart
disease. (Ie, a high-risk group.)
Patients were randomized to first step therapy with: 1) chlorthalidone, 2) amlodipine, or 3)
lisinopril.
Primary outcome measures were fatal
coronary heart disease and non-fatal myocardial infarction.
Results:
A. There were no
significant differences between the 3 drugs in relative risks for the primary outcomes
in patients with DM or NG.
B. A significantly higher
risk was noted for the primary outcome in IGF patients assigned to amlodipine vs chlorthalidone.
C. Stroke was more common
in NG patients assigned to lisinopril vs chlorthalidone.
D. Heart failure was more
common in DM and NG patients assigned to amlodipine or lisinopril vs chlorthalidone.
Conclusion: There was no evidence of
superiority for treatment with a calcium channel-blocker, or an ACE inhibitor
compared with a thiazide-type diuretic during first-step antihypertension therapy in DM, IFG, or NG.
Archives Int Med
June 27, 2005; 165: 1401-09
Original investigation by the ALLHAT Collaborative Research Group, first
author Paul K Whelton,
Likely To Produce Clinically Important Pain Relief.
6-9 EFFICACY AND SAFETY OF OPIOID AGONISTS IN THE
TREATMENT OF NEUROPATHIC PAIN OF NON-MALIGNANT ORIGIN A Systematic Review.
Peripheral neuropathic
pain (NP) includes diabetic
neuropathy, post-herpetic neuralgia, trigeminal neuralgia, and phantom pain after
amputation. Central neuropathic pain
includes post-stroke pain, pain of multiple sclerosis, and post-spinal cord
injury pain.
The main clinical characteristic of
NP is continuous or intermittent spontaneous pain, typically described as
burning, aching, or shooting; and abnormal sensitivity of the painful site to
normally innocuous stimuli such as light touch (allodynia). Pharmacologic
treatment has generally involved use of antidepressants, or anticonvulsants.
Effective pain relief is difficult to
achieve. Use of opioids for NP is controversial. This is in part because
studies have been small, have yielded equivocal results, and have not
established long-term efficacy and safety. There have been concerns about
adverse effects: potential for abuse and
addiction, hormonal abnormalities, dysfunction of the immune system, and
paradoxical hyperalgesia.
This systematic review assessed the
efficacy and safety of opioids for treatment of NP.
Conclusion: Short-term studies (< 24 hours) provided
equivocal evidence of efficacy. Intermediate-term studies (8 to 56 days) demonstrated
significant efficacy. Reported adverse effects were common, but not
life-threatening.
STUDY
1. Literature search
extracted data from randomized, controlled trials of opioid treatment of NP of
any etiology. Drugs included morphine, fentanyl, meperidine, and oxycodone.
2. Excluded trials in
which drugs other than opioid agonists were combined with the opioid. No trials
of epidural or intrathecal opioids were included.
3. Fourteen trials met
inclusion criteria for short-term use (< 24 hours).
4. Eight trials met
inclusion criteria for intermediate-term use (range 8 to 56 days; median = 28
days).
RESULTS
1. In all short-term trials,
opioids were superior to placebo, but reached statistical significance in only
3 of 14. The overall difference in pain intensity was 16 points lower on a
visual analogue 0 to 100 scale
2. All 8 intermediate
trials demonstrated efficacy for reducing pain. A meta-analysis of 6 of the
trials showed mean post-treatment visual analogue scale scores of pain intensity after opioids to be 14 units
lower (compared with placebo) on a scale
of 0 to 100.
3. The
most common adverse effects were nausea, constipation, drowsiness, vomiting,
and dizziness. (NNT to harm one patient
= 4 to 7.)
DISCUSSION
1. “We conclude that
intermediate-term opioid treatment has a beneficial effect over placebo for
spontaneous neuropathic pain for up to 8 weeks of
treatment and that the magnitude of this opioid effect in nearly a 14-point difference
in pain intensity at study end compared with placebo.
”
2. A benefit was achieved
with low to moderate doses. Higher doses may have the potential to produce a greater
effect.
3. Is an average decline
of 14 points on a 100-point scale meaningful to patients? The mean initial pain
intensity ranged from 46 to 69. A 14-point difference corresponds to a 20% to
30% reduction in pain.
4. Despite limited data,
the meta-analysis showed similar responsiveness for pain of central and
peripheral etiologies.
5. The trial did not
address issues of addiction. It is reasonable to assume that the studies did
not include individuals who might be potential abusers.
6. No consistent
improvements in quality-of-life could be demonstrated.
CONCLUSION
Intermediate use (8 weeks or more) is
likely to produce clinically important pain relief.
Reported adverse effects are common,
but not life-threatening.
JAMA June
22/29 2005; 3043-52 Original investigation, first author Elon Eisenberg,
Donepezil May Delay Clinical Progression To Alzheimer’s Disease
6-10 VITAMIN
E AND DONEPEZIL (ARICEPT) FOR THE
TREATMENT OF MILD COGNITIVE IMPAIRMENT
Amnestic (memory loss) mild cognitive impairment (MCI)
represents a transitional state between the cognitive changes of normal aging
and the earliest clinical features of Alzheimer’s disease (AD). Amnestic MCI refers to the
subtype that has a primary memory component, either alone or in conjunction
with other cognitive-domain impairments of insufficient severity to constitute
dementia. About 80% of those who meet the criteria for MCI will have AD within
6 years.
The rate of progression from MCI to
clinically diagnosable AD is 10% to 15% per year. This contrasts to a rate of
1% to 2% per year among normal elderly persons.
The presence of the APOE e4 alleles
is associated with a more rapid rate of progression.
Preventing the progression of MCI to
AD is likely to provide substantial benefit.
Oxidative damage accompanies AD. A
previous large study reported that vitamin E could delay the time to important clinical milestones in patients with
moderately severe AD. Cholinesterase
inhibitors have been recommended for treatment of mild-to-moderate AD.
This study was designed to determine
if vitamin E or the cholinesterase inhibitor donepezil could delay the clinical
diagnosis of AD in patients with MCI.
Conclusion: Vitamin E produced no benefit. Donepezil was
associated with a lower rate of progression during the first 12-24 months.
After 3 years, progression to AD did not differ from those receiving placebo.
STUDY
1. Double-blind trial
enrolled 769 subjects (mean age = 73) with amnestic MCI of insidious onset and
gradual progression of impaired memory. APOE
carriers—55%
2. Criteria for diagnosis of amnestic MCI:
A. A delayed-recall score of 1.5 to 2
standard deviations below the education-adjusted norm.
B. A clinical dementia rating of 0.5.
C. A score of 24 to 30 on the
Mini-Mental State Examination.
D. Age 55 to 90.
3. Baseline means:
Cognitive score = 18 (range 0 to 85,
higher scores indication poorer function.)
MMSE score = 27 (range 0 to 30)
Score for activities of daily living
= 46 (range = 0 to 53, higher scores indicating better function.)
4. Randomized to daily doses of:
A. 2000 IU vitamin E, or
B. 10 mg donepezil, or
C. Placebo.
5. Primary end point = time to development of possible or
probable AD. Follow-up = 3 years.
RESULTS
1. Over 3 years, 212 (28%) developed possible or probable
AD. Overall progression to AD was 16%
per year.
1) Vitamin E group vs
placebo: No significant differences in
progression to AD at any point over the 3 years, including carriers of the APOE
e4 allele. (Hazard ratio = 1.02)
2) Donepezil
group vs placebo:
A. At 12 months, this
group had a reduced likelihood of progression (16 subjects
vs 33). There was a relative reduction in risk of progression of 56% at one
year and 36% at two years.
B. Over 3 years, no significant
differences in progression to AD ( 63 subjects vs 73).
(Hazard ratio = 0.80)
C. APOE e4 carriage was a major
predictor of more rapid progression to AD.
Among carriers of APOE e4 alleles, the
benefit of donepezil was evident throughout the 3 years of follow-up.
2. Memory, language,
global measures of cognition, disease severity, and stage of dementia all
paralleled the overall treatment effect of donepezil
3. Adverse events in
donepezil: muscle cramps; GI symptoms;
sleep disturbance. 29% discontinued treatment (more than in the other 2
groups).
DISCUSSION
1. Over 3 years, there
were no statistically significant differences in the probability of progression
to AD between donepezil, vitamin E, and placebo.
2. Although vitamin E had
no effect at any time, donepezil demonstrated a reduced likelihood of progression
to AD in the first 12 and 24 months.
3. “These results suggest
that donepezil may delay clinical progression to Alzheimer’s disease.”
4. “The observed relative
reduction in the risk of progression of 56% at one year and 36% at two years in
the entire cohort is likely to be clinically significant.”
5. “Although our findings
do not provide support for a clear recommendation for the use of donepezil in persons with mild cognitive impairment, they
could prompt a discussion between the clinician and the patient about this
possibility.”
6. The presence of the APOE
e4 alleles was highly predictive of progression to AD. Most of the treatment
effect of donepezil occurred among APOE e4 carriers. “However, there are
insufficient data to recommend genotyping in persons with mild cognitive
impairment.”
CONCLUSION
Donepezil may delay the clinical diagnosis of
AD, but only for the first year.
The benefit of donepezil was more
prominent among carriers of the APOE e4 gene.
NEJM June 9, 2005; 352:
2379-88 Original investigation by
the Alzheimer’s Disease Cooperative Study Group, first author Ronald C
Petersen, Mayo Clinic College of Medicine,
An editorial in this issue (pp 2439-41 by Deborah Blacker,
“The implications of this study for
primary care medicine and for public health are enormous.” The clear-cut
negative findings of vitamin E are especially noteworthy.
The findings for donepezil are much
less clear.
MCI is a transition state between
normal aging and dementia (for Alzheimer’s disease in particular), one in which
cognitive deficits are present, but function preserved. In clinical settings,
the term is often used to describe patients who present with memory loss, but
do not have dementia. Even when defined carefully, MCI is a heterogeneous
category that includes some persons with memory changes of normal aging, some
with non-progressive cognitive defects, some with prodromal AD, and some with
prodromal forms of other neurodegenerative dementias. Only those on a course
toward AD are likely to benefit from AD-specific interventions.
There is evidence that pathological
changes of AD are already well established in the brain in a substantial
fraction of those with MCI. Attempts to prevent progression are more accurately
viewed as early intervention.
Donepezil is a widely used cholinesterase
inhibitor with limited clinical benefits for treatment of AD. Use is sometimes
equated with a 6-month delay in progression compared with placebo.
Vitamin E is widely used for all
types of patients with AD because of its low cost and perceived safety. It is
also widely used for primary prevention by people with normal cognition.
MCI can now be measured and studied.
. . “Which is no small feat for a syndrome that was
delineated less than a decade ago”.
What lessons does the study offer?
1) Symptoms of memory
loss in older persons should be taken seriously. They may represent the
beginning of AD. This may be an important clinical measure
once more effective treatments become available.
2) Donepezil
may offer some benefit, although limited and transient.
3) Vitamin E is of no benefit in
delaying onset of AD.
In Modestly Overweight Persons, Reduction In Weight May Lower
Risk Of Developing Hypertension.
6-11 WEIGHT LOSS IN OVERWEIGHT ADULTS AND THE
LONG-TERM RISK OF HYPERTENSION: The
Excess body weight is the strongest
known risk factor for hypertension. Its adverse effects begin in childhood.
Obesity is notoriously difficult to
treat. The great majority of patients who lose weight subsequently regain it.
In patients with hypertension, weight
loss, whether alone, or in combination with medication, has a beneficial effect
on BP control.
Previous analyses of overweight
subjects from the Framingham Study showed that change in weight was associated
with a linear change in BP, and sustained weight loss was associated with a 30%
reduction in the incidence of type 2 diabetes.
The goal of this study was to
estimate the effects of both the amount on weight loss and the persistence of
weight loss on the risk of incident hypertension among already obese adults. (Primary prevention.)
Conclusion: A modest weight loss, particularly when
sustained, substantially lowered the long-term risk of developing hypertension.
STUDY
1. Evaluated weight loss
among over 1200 overweight (BMI over 25) non-hypertensive subjects in a group
of patients aged 30-49, and another group age 50-65. None were hypertensive at
baseline.
2. Characteristics of subjects age 30-49 (means) at baseline:
Age = 27 BMI =
27 BP =
124/80
3. Characteristics of subjects age 50-65 (means) at baseline:
Age = 52 BMI = 28 BP = 124/79
(Note—these
subjects were not considered obese; this degree of elevation of BMI is
extremely common.)
4. Classified subjects according to the amount of weight loss
over 4 years:
1) Weight loss less than 1.8 KG
2) Loss 1.8 to 3.6 kg.
3) Loss 3.6 kg to 6.8 kg.
4) Loss over 6.8 kg.
4. Also classified weight loss according to whether it was
sustained during the next 4 years.
5. Determined onset of hypertension over the years (up to 48
years).
RESULTS
1. After multiple
adjustments, weight loss of 6.8 kg (18 pounds) or more led to a 28% reduction
in risk of developing long-term hypertension in younger subjects, and a 37% reduction
in older subjects.
2. If the weight loss was
sustained over the years, the risks of developing hypertension were reduced by 22% and
26%.
DISCUSSION
1. For primary prevention
of hypertension in modestly overweight persons, there may be significant
long-term reduction in onset of hypertension related to modest weight. (Primary prevention)
2. Obesity is associated
with higher levels of insulin resistance, hyperinsulinemia, rises in cardiac
output, increases in cholesterol and triglycerides, and increased sympathetic
nervous system activity. Most of these changes have been associated with
increases in BP. “In recent years, there has been a great deal of focus on the
roles of hyperinsulinemia and insulin resistance in the development of
hypertension.”
3. “The results of this
study suggest that at least 15% of the cases of hypertension in overweight
middle-aged adults and 22% of the cases occurring in overweight older adults
could be prevented by a modest amount of sustained weight loss.”
Archives Int Med June 13, 2005; 165: 1298-2005 Original investigation, first author Lynn L
Moore, Boston University School of Medicine, Mass.
Treatment Reduced Serious Perinatal Morbidity In Infants And May Improve The Woman’s Health-Related
Quality Of Life.
6-12 GESTATIONAL DIABETES MELLITUS; Effect Of Treatment
On Pregnancy Outcomes.
Gestational
diabetes mellitus (GDM) occu1rs in
up to 9% of all pregnancies. It is associated with substantial maternal and perinatal
complications. Neonatal complications include macrosommia, shoulder dystocia,
birth injuries, bone fractures, nerve palsies, and hypoglycemia. Long-term
adverse health outcomes among infants born to mothers with GDM include
sustained glucose intolerance, subsequent obesity, and impaired intellectual
achievement.
For the mother, GDM is a strong risk
factor for type 2 diabetes and may be related to increased risk of anxiety,
depression, and impaired health status.
This study asked…Does screening and
treatment for GDM reduce these risks?
Conclusion: Treatment of GDM reduced
serious perinatal morbidity in infants and may improve the woman’s
health-related quality of life.
STUDY
1. Enrolled 1000 women who were between 16 and 30 weeks
pregnant.
All had onset or recognition of GDM during
the present pregnancy with:
A. A positive 50-g oral glucose tolerance
challenge test (glucose level one hour after glucose challenge of 140 mg/dL or more) and,
B. A 75-g oral glucose
tolerance test at 24 to 34 weeks in which the fasting plasma glucose was less
than 140 mg/dL, two hour p.c. glucose was 140 to 198 mg/dL at. (Intermediate between the normal and diabetic response.
2. Women with more severe glucose intolerance were excluded.
3. Randomly assigned to:
A. Intervention group: (n = 490)
1) Ongoing care by obstetrical team.
2) Individualized dietary
advice taking into account the woman’s pre-pregnancy weight, activity level,
and weight gain.
3) Instructions in
self-monitoring glucose levels at least 4 times a day. Monitoring continued
until achieving a fasting glucose of at least 63 mg/dL and no more than 99, and
pre-prandial levels no more than 99, and 2-hour post-prandial no more than 126.
4) Insulin therapy with dose adjusted
on the basis of glucose levels.
B. Routine care group: (N = 510)
Women and caregivers were not aware
of their diagnosis of glucose intolerance of pregnancy. This care replicated
clinical care in which screening for GDM is not available.
RESULTS
1. Infants:
A. Serious perinatal complications in
infants were significantly lower in the intervention group
(1% vs 4%). The NNT to prevent one serious
outcome in infants = 34.
B. Birth weights were lower in the
intervention group. (less likely to have macrosommia.)
C. No difference in rate of
hypoglycemia requiring intravenous glucose.
2. Women:
A. Insulin therapy was
given to 20 % in the intervention group vs
3% in the usual care group.
B. Rate of caesarean
deliveries was similar.
C. Women in the
intervention group gained less weight and had less risk for preeclampsia.
D. At 3-months
postpartum, women in the intervention group had lower rates of depression and
higher scores on quality-of-life.
DISCUSSION
1. Treatment of GDM reduced the rate of serious perinatal complications
in infants.
2 “Our trial revealed an
improved health-related quality-of-life among women in the intervention group,
both during the antenatal period and three months after birth, together with a
reduction in the incidence of depression after birth.”
3. Is it ethical to withhold the diagnosis of GDM as was done
in the routine care group?
The authors defend their decision not
to inform these women:
A. At the time of the
study, there continued to be no conclusive evidence regarding the treatment of
GDM. There were wide variations in clinical practice at the time.
B. Women in the
non-intervention group received standard pregnancy care consistent with care in
which screening for GDM is not routine.
CONCLUSION
Treatment of GDM in the form of
dietary advice, blood glucose monitoring, and insulin therapy as required for
glucose control, reduced the rate of serious perinatal complications without
increasing the rate of caesarean delivery.
NEJM June 16, 2005; 352: 2477-86 original investigation, by the Australian
Carbohydrate Intolerance Study in Pregnant Women (ACHOIS) Trial Group, first
author Caroline A Crowther,
An editorial in this issue of NEJM,
first author Michael F Greene, comments:
There is a worrisome rise in
prevalence of GDM that is largely related to the increase in maternal obesity.
GDM is broadly defined as
carbohydrate intolerance beginning, or first recognized, during pregnancy. It
has been the subject of controversy for decades. The US Preventive Services
Task Force, noting the absence of data, concluded that the evidence is
insufficient to recommend for or against routine screening.
Evidence has remained largely
observational.
“This study provides critical evidence
that identifying and treating gestational diabetes mellitus can substantially
reduce the risk of adverse perinatal outcomes without, at least in this trial,
increasing the rate of caesarean delivery.”
Of note: the glucose levels currently
recommended by US organizations to identify GDM differ. Their accepted
criterion is two or more values on a 100 g oral glucose tolerance test at or
above:
Fasting 95 mg/dL
One hour 180
Two hours 155
Three hours 140
The target levels during treatment
were similar to those in the study.
=====================================================================================
The Test Could Be Used As An Initial Approach To Diagnosis.
6-13 IS PROTON PUMP INHIBITOR TESTING AN
EFFECTIVE APPROACH TO DIAGNOSE GASTRO ESOPHAGEAL REFLUX DISEASE IN PATIENTS
WITH NON-CARDIAC PAIN? A Meta-analysis
Non-cardiac chest pain (NCCP) is defined as recurrent episodes
of retrosternal pain which lack cardiac abnormalities. NCCP is extraordinarily
common, the annual prevalence estimated at above 25% of the population. These
patients consume a large proportion of health care resources.
Gastro esophageal reflux disease
(GERD) is the most common cause.
Endoscopy, 24-hour esophageal pH monitoring,
and esophageal manometry are used to evaluate these patients. The sensitivity
of endoscopy is limited because most patients have non-erosive GERD. Esophageal
pH monitoring is invasive, costly, and often unavailable.
Patients with NCCP are often treated
empirically and successfully with proton pump inhibitors.
Can proton pump inhibitors be used as
a diagnostic test?
This study evaluated the overall
accuracy of the test.
Conclusion: In primary care, the test could be used as an
initial approach to diagnosis.
STUDY
1. This systemic review
and meta-analysis included 6 randomized, placebo-controlled trials evaluating
the accuracy of proton pump vs
placebo testing in patients with NCCP and suspected GERD.
2. GERD was confirmed by
endoscopy and/or 24-hour esophageal pH monitoring.
3. The trials included
220 patients. Prevalence of GERD among
these patients with NCCP varied from 33% to 76%
4. Lansoprazole (Prevacid) and omeprazole (Prilosec) were most often the drugs
used.
5. For each study, the
authors calculated sensitivity and specificity using a cut-point of 50% or more
relief of discomfort. (> 50% relief as judged by the patient was considered
a positive test; < 50% a negative test.)
RESULTS
1. Results of the PPI test:
GERD present GERD
absent
Positive test (> 50% relief) 80% (true positive)* 26% (false positive)
Negative test (< 50% relief) 20% (false negative) 74% (true negative test)**
(* sensitivity of the PPI test = true + % = 80%; **
specificity of the PPI test = true negative % = 74%)
2. Results of the placebo test:
Positive test (> 50% relief) 19% (true positive)*** 23% (false positive)
Negative test (< 50% relief) 81% (false negative) 77% (true negative test)****
(*** sensitivity of placebo test
=19%; **** specificity of placebo test = 77%)
3. Thus 80% responded
favorably to PPI vs 19% to
placebo. (The authors considered this
difference to be discriminative and to indicate that the PPI test had “acceptable”
sensitivity and specificity for diagnosing GERD.)
DISCUSSION
1. “Our results show that
the sensitivity of the PPI test was significantly
higher than that for placebo; whereas the specificity was almost the same
between both groups.”
2. Treatment with PPIs
and placebo showed similar effects (26% and 23%) on improving NCCP symptoms in
patients without GERD, indicating a possible placebo effect. “The considerably
higher placebo effect is not uncommon in patients with functional bowel
disorders and not surprising in patients with non-GERD-related NCCP.”
3. “The accuracy of a
diagnostic test should be evaluated by comparing its results with a gold
(reference) standard. However, this is not available for the diagnosis of GERD.
The sensitivity of symptom evaluation falls short of a gold standard.
4. The sensitivity of the
PPI test seems to be related to the duration of the treatment. Extending
treatment to 4 weeks increases sensitivity.
5. Sensitivity and
specificity can be increased if reflux symptoms are also evaluated.
6. There are differences
in the definition of NCCP, the type and dosage of PPI used, the washout period,
degree of blinding, execution of the test, and reference standard for
diagnosing GERD. “Biases may exist.”
CONCLUSION
The use of PPI as a diagnostic test
for detecting GERD in patients with NCCP has an “acceptable” sensitivity and
specificity and could be used as an initial approach by primary care physicians
to detect GERD in selected patients with NCCP.
Archives Int Med June 13, 2005; 165: 1222-28 Original investigation, a meta-analysis,
first author Wei Hong Wang,
The authors suggest the sensitivity
and specificity of the PPI test is “acceptable”. What is “acceptable”? Acceptability of a test
may be judging the pre-test likelihood of the disease being present modified by
the likelihood ratios of the test:
1) Assume that, in your
clinical judgment based on symptoms, signs, and knowing the patient’s clinical history
and personality, you believe there is a 50% likelihood that her NCCP is due to
GERD. (The pretest likelihood = 50%)
2) A positive test—in this example, relief of
discomfort of 50% or more—can be either a true positive (80%) or a false
positive (20%).
The positive likelihood
ratio is simply the ratio between true positive tests and false positive tests:
80/20 = 3.1.
In this example, if we
assume the pretest probability that GERD is present, is 50%, a positive test
will increase the probability that the disease is present. A nomogram is used
to calculate the resultant post-test probability. In this example the positive
test increased the probability that the disease is present from 50% to 75%.
3) A negative test—in
this instance relief of discomfort of less than 50%--can be either a false
negative (20%) or a true negative (74%)
The negative likelihood
ratio is simply the ratio between false negative tests (20%) and true negative
tests (74%): 20/74 = 0.27
Using the nomogram again, the negative test lowered the probability
that the disease is present from 50% to 21%
If other clinical markers were present
(eg, reflux symptoms) our clinical judgment would likely increase the pre-test
probability that GERD is present. The post-test probability would then be
higher.
Both the positive likelihood ratio
and the negative likelihood ratio were modestly helpful in this study. If the
positive likelihood ration had been 10, the disease would be effectively
confirmed. If the negative likelihood ratio were 0.1, the disease would have
been effectively ruled out.
To obtain a nomogram and an excellent
description of likelihood ratios go to GOOGLE and access “likelihood ratios”,
presented by the Centre for Evidence-Based Medicine.
May Reduce Risk Of Development Of PMS.
6-14 CALCIUM
AND VITAMIN D INTAKE AND RISK OF INCIDENT PREMENSTRUAL SYNDROME
Up to 90% of premenopausal women
regularly experience affective and /or physical symptoms before the onset of
menses. Up to 20% experience symptoms that meet the clinical definition of
premenstrual syndrome (PMS), a
disorder characterized by moderate to severe symptoms which substantially
interfere with normal activities and interpersonal relationships. Symptoms are
limited to the luteal phase of the cycle, and abate shortly after onset of
menses.
Oral contraceptives,
gonadotropin-releasing hormone agonists and serotonin reuptake inhibitors have
been used as therapy. They have adverse effects and can be expensive.
Alternatives such as dietary
supplements are being evaluated.
Several studies have suggested that
calcium and vitamin D levels are lower in women with PMS, and that calcium
supplementation may prevent the initial development of PMS.
This study asked: Would calcium and vitamin D prevent the initial development of PMS?
Conclusion: A high intake of dietary calcium and dietary vitamin
D may reduce risk of development of PMS.
STUDY
1. This case-control
study was nested within the large prospective Nurses’ Health Study.
Participants were a subset of women age 27 to 44 (mean = 35). All were free of PMS at baseline
(1991).
2. Cases: 1057 women who developed PMS over a 10-year
follow-up.
3. Controls: 1968 women who reported no diagnosis of PMS
and no, or minimal, menstrual symptoms.
4. Determined dietary and
supplemental intakes of calcium and vitamin D by periodic questionnaires.
RESULTS
1. After adjustment for
age, parity, and smoking status, and other risk factors, women in the highest
quintile of total vitamin D intake (median of 706 IU) had a relative risk of
new-onset PMS of 0.59 compared with those in the lowest quintile (median of 112
IU). Benefit was associated with vitamin D from food. Supplemental vitamin D
did not seem to be associated with risk.
2. The intake of calcium
from food sources was also inversely related to onset of PMS; compared with
women with a low intake (median 529 mg/d), women with the highest intake
(median 1283 mg/d) had a relative risk of 0.70. Calcium from supplements was
not associated with risk—only calcium from food.
3. The intake of skim or
low-fat milk was also associated with a lower risk. Participants consuming 4 servings/d
or more of skim or low-fat milk had a RR of developing PMS of 0.54 compared with
women who consumed 1 serving or less per week.
4. Whole milk intake was
associated with a modest increase in
development of PMS
DISCUSSION
1. “Findings from our
nested case-control study suggest that a high dietary intake of vitamin D and
calcium may lower the risk of incident
PMS.” There was a significantly lower
risk of developing PMS in women with a high intake of vitamin D and calcium
from food sources such as skim or low-fat milk, fortified orange juice, and
low-fat dairy foods such as yogurt. These dietary (not supplemental) intakes
correspond to approximately 1200 mg of calcium and 400 IU of vitamin D daily.
2. The authors state that
the data regarding supplemental calcium are not firm.
3. Why should calcium be
protective? The authors suggest that calcium and vitamin D may influence development
of PMS through a relationship to endogenous estrogens and parathyroid hormones.
4. This may be an added
inducement for women who wish to reduce their risk of osteoporosis.
CONCLUSION
A high intake of dietary calcium and
dietary vitamin D may reduce the risk of developing PMS.
Archives Int Med June 13, 2005; 165: 1246-52 Original investigation, first author
Elizabeth R Bertone-Johnson,
Hope For Reducing The Prevalence Of This World-Wide Scourge.
6-15 BASIC SCIENCE GUIDELINES DESIGN OF NEW TB
VACCINE CANDIDATES
A number of new vaccine candidates
are being entered into phase 1 clinical trials.
The BCG (Bacillus Calmette-Guerlin)
was developed almost 100 years ago. It is still being used in many parts of the
world, It is an attenuated live vaccine made from a
strain of the bacterium that causes TB in cattle (Mycobacterium bovis). Its efficacy in protecting individual against
TB is variable.
Attempts are being made to improve
the existing BCG vaccine. One approach
is to add an extra copy of the gene for a major secretory protein of an M
tuberculosis antigen. The standard BCG vaccine contains this gene,
the extra copy causes the antigen to be made in greater amounts. This results
in a stronger immune response.
Another approach is to add a gene
from Listeria monocytogenes. This
stimulates a vigorous CD8 T-cell response in addition to the CD4 response. CD8
T-cells also contribute to protection against M tuberculosis.
Another approach is to prime with a
BCG vaccine and then boost the immune response with a different TB
vaccine—either a subunit vaccine or a live vaccine.
Still another, the furthest along in
clinical trials is a viral vector (a modified vaccinia virus) to which has been
added an antigen similar to that in the BCG vaccine. It is given as a booster
to persons who have received the BCG vaccine.
It . . .”Produces an overwhelming CD4 T-cell response”. This vaccine is
presently being tested for use in individuals who are latently infected with
TB. If successful, this should have a much more immediate impact on the burden
of morbidity and mortality.
Others are being investigated. Safety
is the main concern.
JAMA June 8, 2005; 293:
2704-05 “Medical News and
Perspectives” editorial by M J Friedrich, JAMA Staff.
While this is not a practical point, it was enticing enough for me to
abstract.