Evidence Based Medicine Story Hale Arık Taşyıkan MD MPH Department of Public Health Yeditepe University Do we really know what makes us healthy What ID: 676537
Download Presentation The PPT/PDF document "The R i se and Fall of Hormone Replace..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
The Rise and Fall of Hormone Replacement Therapy
Evidence Based Medicine Story
Hale Arık Taşyıkan, MD, MPH
Department
of
Public
Health
Yeditepe
University
Slide2
Do we really know
what makes us healthy?
What
if it is just bad
science
?Slide3
Hormone Replacement TherapyBy the mid-1990s, hormone replacement therapy (HRT) had become one of the most widely prescribed medications for women, especially in North America. Slide4
Observational Studies Observational studies Showed cardiovascular benefit for HRT.
Nurses
’ Health Study (1991)
48,470
postmenopausal
women
30 -63 years oldNo history of cancer or CVD at baseline10 years follow-upAfter adjustment for age and other risk factors: RR of major coronary disease in women currently taking estrogen was 0.56 (CI: 0.40 – 0.80)Slide5
Nurses’ Health StudySlide6
Nurses’ Health StudyCONCLUSION:
The
investigators concluded that «current estrogen use is associated with a reduction in
the
incidence
of
coronary heart disease as well as in mortality from cardiovascular disease» Slide7
Observational StudiesSystematic review of observational studies, 1992:Pooled RR: 0.65 (35% reduction in CHD)
«
There is evidence that estrogen therapy decreases risk for CHD,…hormone therapy should probably be recommended for women who have had a
hysterectomy
and
for those with CHD or at high risk for CHD» Slide8
Randomized Trial of Estrogen Plus Progestin for Secondary Prevention
of
Coronary Heart Disease in Postmenopausal WomenAim: To determine if estrogen plus progestin therapy alters the risk for CHD events in postmenopausal women with established coronary disease
Study
Design:
Randomized, blinded, placebo-controlled secondary prevention
trial
Setting: Outpatient and community settings at 20 US clinical centersPopulation: A total of 2763 women with coronary disease, younger than 80years, and postmenopausal with an intact uterus. Mean age was 66.7 years.Slide9
Randomized Trial of Estrogen Plus Progestin for Secondary Prevention
of
Coronary Heart Disease in Postmenopausal WomenIntervention: Either 0.625 mg of conjugated equine estrogens plus 2.5 mg of medroxyprogesterone acetate in 1 tablet daily (n = 1380) or a placebo of identical
appearance
(n = 1383).
Follow-up
:
Averaged 4.1 years; Lost to follow-up: 82% of those assigned to hormone treatment were taking it at the end of 1 year, and 75%at the end of 3 yearsOutcome: The primary outcome was the occurrence of nonfatal myocardial infarction (MI) or CHD deathSlide10Slide11Slide12
Risks and Benefits of Estrogen Plus Progestinin Healthy Postmenopausal WomenPrincipal Results From the Women’s Health Initiative
Randomized
Controlled Trial (2002)Aim: To assess the major health benefits and risks of the most commonly used combined hormone preparation in the United States.Study Design:
Estrogen plus progestin component of the Women’s Health Initiative, a
randomized
controlled
primary prevention trial (planned duration, 8.5 years).Population: 16608 postmenopausal women aged 50-79 years with an intact uterus at baseline were recruited by 40 US clinical centers in 1993-1998.Slide13
Risks and Benefits of Estrogen Plus Progestinin Healthy Postmenopausal WomenPrincipal Results From the Women’s Health Initiative
Randomized
Controlled TrialIntervention: Participants received conjugated equine estrogens, 0.625 mg/d, plus medroxyprogesterone acetate, 2.5 mg/d, in 1 tablet (n=8506) or placebo (n=8102)Follow-up
:
A
fter
a mean of 5.2 years of follow-up, the data and safety monitoring board recommended stopping the trial of estrogen plus progestin vs placebo because the test statistic for invasive breast cancer exceeded the stopping boundary for this adverse effect and the global index statistic supported risks exceeding benefits.Slide14
Risks and Benefits of Estrogen Plus Progestinin Healthy Postmenopausal WomenPrincipal Results From the Women’s Health Initiative
Randomized
Controlled TrialOutcome: The primary outcome was coronary heart disease (CHD) (nonfatal myocardial infarction and CHD death), with invasive breast cancer as the primary adverse outcome. A global index summarizing the balance of risks and benefits
included
the 2 primary outcomes plus stroke, pulmonary embolism (PE),
endometrial
cancer, colorectal cancer, hip fracture, and death due to other causes.Slide15Slide16
Risks and Benefits of Estrogen Plus Progestinin Healthy Postmenopausal WomenPrincipal Results From the Women’s Health Initiative
Randomized
Controlled TrialConclusion: Overall health risks exceeded benefits from use of combined estrogen plus progestin for an average 5.2-year follow-up among healthy postmenopausal US women. All-cause mortality was not affected during the trial. The risk-benefit profile found in this trial is not consistent with the requirements for a viable intervention
for
primary
prevention of chronic diseases, and the results indicate that this regimen
should not be initiated or continued for primary prevention of CHD.Slide17
Biases???Healthy user biasPeople who faithfully engage in activities that are good for them — taking a drug as prescribed, for instance, or eating what they believe is a healthy diet — are fundamentally different from those who don't. One thing epidemiologists have established with certainty, for example, is that women who take HRT
differ
from those who don't in many ways, virtually all of which associate with lower heart-disease risk: they're thinner; they have fewer risk factors for heart disease to begin with; they tend to be more educated and wealthier; to exercise more; and to be generally more health conscious.Slide18
Biases???Healthy continuer – Compliance
or adherer effect (bias
)
Individuals
who comply or adhere with their doctors'
orders
when given a prescription are different and healthier than people who don't. Those who took HRT everyday, in all likelihood, did other things that may have reduced their risk of heart disease (avoid smoking, daily exercise, better diet, etc.).Slide19
Biases???Lack of adequate adjustment
for bias due to
SES
Observational
studies
did adjust for confounding, but probably residual confounding remained. In a BMJ editorial entitled "The scandal of poor epidemiological research", the authors pointed out that; a protective effect of HRT was evident in studies that did not control for socioeconomic status, but not in studies that did. Higher socioeconomic position is strongly associated with both more frequent use of hormone replacement therapy and lower risk of coronary heart disease. Slide20
Biases???Lack of adequate adjustment
for bias due
to
SES
Meta-analysis
of cohort studies and
case-control studies of hormone replacement therapy and coronary heart disease. There is little evidence for a protective effect when analyses are adjusted for, in contrast to studies not adjusted for, socioeconomic status.Slide21
SummaryBy the mid-1990s, hormone replacement therapy (HRT) had become one of the most widely prescribed medications for women, especially in North America. Several observational studies had shown that women who took long-term estrogen replacement therapy had lower risk of cardiovascular disease. In the late 1990s, a clinical trial called HERS [Heart and Estrogen-progestin Replacement Study], found that
estrogen therapy increased, rather than decreased, the likelihood that women who already had heart disease would suffer a heart attack. Slide22
SummaryIn 2002, a second trial, the Women's Health Initiative [WHI], concluded that HRT constituted a potential health risk for all postmenopausal women. Randomized trials had suddenly over-turned the long-held belief (from observational studies) that HRT was beneficial for prevention of heart disease. Subsequently, the use of HRT declined worldwide. Slide23
ConclusionObservational epidemiologic studies should always be interpreted cautiously, because confounding is almost always likely, and not all studies are able to prevent or adjust for confounding adequately. The HRT story also reminds us that repeated observational studies can consistently show the same effect, but all can be consistently biased! Lastly, new therapies and interventions must be subjected to rigorous
randomized controlled trials, before they become widely usedSlide24
Conclusion Epidemiology is that it's not enough to just measure one
thing
very accurately. To get the right answer, you may have to measure a great many things very accurately. Slide25
Source: The B files – Case studies of bias in real life epidemiologic studies Department of Epidemiology, Biostatistics and occupational
health, McGill University, Montreal, Canada