Background: Recent trials reveal no benefit and possible harm from chronic hormone replacement therapy (HRT). Less is known about intermediate-term outcomes associated with HRT use in the setting of acute coronary syndromes (ACS).
Methods: To examine the prevalence of HRT use and relationships with intermediate-term outcomes among women with ACS, we classified as HRT users or nonusers 4029 postmenopausal women (age > 50 years or postmenopausal by case report form) randomized in the Sibrafiban versus Aspirin to Yield Maximum Protection from Ischemic Heart Events Post-Acute Coronary Syndromes (SYMPHONY) and 2nd SYMPHONY trials. Outcomes included 90-day and 1-year death and 90-day stroke, death, or myocardial infarction (MI); death, MI, or stroke; and death, MI, or severe recurrent ischemia (SRI).
Results: HRT use was 13% overall and varied by region (Asia, 0%; Eastern Europe, 0.2%; Latin America, 0.8%; Western Europe, 4%; Australia/New Zealand, 12%; Canada, 14%; United States, 24%); estrogen-only regimens were most common (90%). HRT users were younger, had higher estimated creatinine clearance, more frequently were smokers and had prior revascularization, but less frequently had diabetes, prior angina, or heart failure. Unadjusted 90-day and 1-year mortality rates were lower among HRT users (hazard ratios [95% CI] 0.48 [0.23-0.98] and 0.35 [0.18-0.68], respectively) but after multivariable adjustment, were not significantly different. Ninety-day stroke and composite end points did not differ between HRT users and nonusers.
Conclusions: HRT use (predominantly estrogen-only) was low among patients with ACS but varied by region and was not associated with improved intermediate-term outcomes. These results are consistent with the absence of benefit from HRT use (combination or estrogen only) in previous studies in more stable populations.