Sex-Stratified Trends in Enrollment, Patient Characteristics, Treatment, and Outcomes among Non-ST-Segment Elevation Acute Coronary Syndrome Patients: Insights from Clinical Trials over 17 Years

Background - Adequate representation by sex in trials allows generalizability of results. We examined representation of women in clinical trials during a 17-year period in which inclusion criteria were broadened and federal mandates for representativeness were launched. Methods and Results - Using mixed models, we studied sex-stratified temporal trends in enrollment, clinical characteristics, treatment, and outcomes among 76 148 non-ST-segment elevation acute coronary syndrome patients using patient-level data merged from 11 phase III trials conducted from 1994 to 2010. Overall, 33.3% of patients were women, which changed minimally over time. Women were consistently 4 to 5 years older than men (median age 68 [interquartile range 61-75] versus 64 [interquartile range 56-72] years) and more frequently had diabetes mellitus, hypertension, and heart failure; men more frequently had prior myocardial infarction and revascularization. GRACE risk scores increased over time for both sexes with the inclusion of older patients with more comorbidities. Use of percutaneous coronary intervention, in-hospital and discharge angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers, β-blockers, and lipid-lowering drugs also increased among both sexes. Kaplan-Meier estimates of 6-month mortality declined from 7.0% [95% confidence interval 6.5%-7.6%] to 4.5% [95% confidence interval 4.0%-5.0%] among women and 6.3% [95% confidence interval 6.0%-6.7%] to 3.1% [95% confidence interval 2.9%-3.4%] among men during the 17-year period. Conclusions - The relative proportion of women in non-ST-segment elevation acute coronary syndrome trials changed minimally over time. Nevertheless, in parallel with men, use of evidence-based care and outcomes improved significantly over time among women.