RT Journal
A1 Petitti DB
T1 Hormone replacement therapy and heart disease prevention: Experimentation trumps observation
JF JAMA
JO JAMA
YR 1998
FD August 19
VO 280
IS 7
SP 650
OP 652
DO 10.1001/jama.280.7.650
UL http://dx.doi.org/10.1001/jama.280.7.650
AB 
Three different meta-analyses1- 3
have concluded that estrogen replacement therapy (ERT) decreases the risk
of coronary heart disease (CHD) by 35% to 50%. The predicted increase in life
expectancy in hormone users, based on estimates of the risk of CHD in users
of ERT derived from observational studies, is 2 to 3 years.2,4
The effects of ERT and combined estrogen-progestin replacement therapy (HRT)
on lipids and fibrinolysis are strongly beneficial for both ERT and HRT.5 This has led to extrapolation of the results of observational
studies of ERT to HRT and to promotion of the use of both ERT and HRT in women
with CHD.2,6 The results of the
Heart and Estrogen/progestin Replacement Study (HERS), which are reported
by Hulley et al in this issue of JAMA,7 add
critically important data on the effects of HRT. In this randomized controlled
trial of 2763 postmenopausal women with established coronary disease, treatment
with estrogen plus progestin did not reduce the rate of CHD events (eg, nonfatal
myocardial infarction or CHD-related death). These findings are a sobering
reminder of the limitations of observational research, the incompleteness
of current understanding of the mechanisms of vascular disease, and the dangers
of extrapolation.