Women were found to be at a lower risk for major adverse cardiovascular events (MACE) after non-ST-segment elevation acute coronary syndromes (NSTEACS) compared with men, according to a study published in the Journal of the American College of Cardiology.
Investigators conducted a sex-specific analysis of cardiovascular outcomes after NSTEACS, using the data from 10 phase 3 clinical trials conducted since 2000 by the Thrombolysis in Myocardial Infarction Study Group. In all trials, >2500 participants were included within 30 days of hospitalization for an index NSTEACS event. The primary outcome was the MACE composite of stroke, myocardial infarction, or cardiovascular death. Secondary outcomes included all-cause mortality and incidence rates of individual MACE components.
Multivariable adjusted Cox proportional hazard modeling was used to assess the relationship between sex and MACE for each trial, and random effects models then combined the individual adjusted point estimates.
The data for 68,730 patients with NSTEACS were analyzed, consisting of 19,827 women (28.8%; mean age, 67 years; 23.6% aged ≥75 years; 85.9% white) and 48,903 men (71.2%; mean age, 62 years; 13.4% aged ≥75 years; 87.3% white). Mean follow-up time was 676 days. Female participants were older and had higher prevalences of renal dysfunction, diabetes mellitus, hypertension, and history of heart failure (P <.001 for all); male patients were more likely to be current smokers and to have histories of myocardial infarction or percutaneous coronary intervention (P <.001 for all).
In the unadjusted analysis, women had a MACE risk comparable with that of men (hazard ratio [HR], 1.04; 95% CI, 0.99-1.09; P =.16; heterogeneity factor, I2 <.0001%), but an increased risk for all-cause mortality (HR, 1.12; 95% CI, 1.01-1.24; P =.03; I2 =38.63%), stroke (HR, 1.19; 95% CI, 1.03-1.37; P =.02), and cardiovascular death (HR, 1.16; 95% CI, 1.02-1.32; P =.03). The risk for myocardial infarction was comparable in men and women (HR, 1.00; 95% CI, 0.94-1.06; P =.94).
After accounting for baseline differences, the risks for MACE (adjusted hazard ratio [aHR], 0.93; 95% CI, 0.88-0.98; P =.006; I2 =.001%), all-cause death (aHR, 0.84; 95% CI, 0.78-0.90; P <.0001; I2 =.02%), and cardiovascular death (aHR, 0.85; 95% CI, 0.76-0.96; P =.008) were found to be lower in women vs men. There were no significant differences between women and men for the risks for myocardial infarction (aHR, 0.96; 95% CI, 0.91-1.03; P =.23) and stroke (aHR, 0.91; 95% CI, 0.75-1.10; P =.35).
Study strengths include rigorous outcome ascertainment and a well-characterized population. Study limitations include possible residual confounders, discrepancies in trial designs and parameters, and predominantly white patient samples.
“Our analysis…advances our knowledge by showing that the excess risk observed among women vs men was primarily explained by differences in age and baseline risk profiles rather than female sex itself in this dataset,” noted the authors.
Sarma AA, Braunwald E, Cannon CP, et al. Outcomes of women compared with men after non–ST-segment elevation acute coronary syndromes. J Am Coll Cardiol. 2019;74(24):3013-3022.