Bm. Psaty et al., THE RISK OF MYOCARDIAL-INFARCTION ASSOCIATED WITH THE COMBINED USE OFESTROGENS AND PROGESTINS IN POSTMENOPAUSAL WOMEN, Archives of internal medicine, 154(12), 1994, pp. 1333-1339
Background: While observational studies have suggested that unopposed
estrogens reduce the incidence of coronary disease in postmenopausal w
omen, there are few data on the effect of combined therapy with estrog
ens and progestins-a regimen adopted in recent years to minimize the r
isk of endometrial hyperplasia and cancer. In clinical trials, the add
ition of progestins has an adverse effect on serum lipid levels, and t
hese lipid effects have raised the question of whether combined estrog
en-progestin therapy increases the risk of coronary disease compared w
ith the use of estrogen alone. Methods: We conducted a population-base
d, case-control study among enrollees of Group Health Cooperative of P
uget Sound. Cases were postmenopausal women who sustained an incident
fatal or nonfatal myocardial infarction in 1986 through 1990. Controls
were a stratified random sample of female Group Health Cooperative en
rollees frequency matched to the cases by age and calendar year. We re
viewed the medical records of the 502 cases and 1193 controls and cond
ucted brief telephone interviews with consenting survivors. The health
maintenance organization's computerized pharmacy database was used to
ascertain the use of postmenopausal hormones. For the primary analysi
s of current use, we classified women into one of three groups: (1) no
nusers of hormones; (2) users of estrogens alone; or (3) users of comb
ined therapy including both estrogens and progestins. Each group of ho
rmone users was compared with nonusers. Results: After adjustment for
potential confounding factors, the risk ratio of myocardial infarction
associated with current use of estrogens alone was 0.69 (95% confiden
ce interval, 0.47 to 1.02); and the risk ratio of myocardial infarctio
n associated with current use of combined therapy was 0.68 (95% confid
ence interval, 0.38 to 1.22). Duration of combined-therapy use was rel
atively short, averaging less than 2 years in cases and controls. Conc
lusions: In this case-control study, the reduced risk of myocardial in
farction associated with the use of estrogens alone was consistent wit
h previous observational studies. Although the 95% confidence interval
only excluded a risk above 1.22, the current use of combined therapy
was not associated with an adverse effect on the incidence of myocardi
al infarction in postmenopausal women.