Sex Differences in Characteristics and Outcomes among Low-Risk Non-ST-Elevation Acute Coronary Syndrome Patients during Long Term Follow-Up

Abstract

Previous heterogenous studies show conflicting data about sex-based outcomes of non-ST-elevation acute coronary syndrome (NSTE-ACS) patients. This study evaluated 300 NSTE-ACS patients undergoing a coronary angiography between September 2012 and May 2015 that were managed with all-treatment strategies. The sample was stratified by sex and analyzed for the baseline characteristics and outcomes. The main outcome included major adverse cardiovascular and cerebrovascular events (MACCE), which were a composite of cardiac death, nonfatal myocardial infarction, ischemic stroke or urgent coronary revascularization. The female patients were older (median of 69.0 vs. 63.0 years, p = 0.008) and had lower values of BMI (median of 26.3 vs. 28.2 kg/m², p < 0.001) and eGFR (76.44 ± 22.43 vs. 94.04 ± 27.91 mL/min, p < 0.001). There was no significant difference in the treatment strategies, angiographic characteristics and discharge therapy between the groups (p > 0.05). The female patients had significantly higher unadjusted rates of ischemic stroke (4.2% vs. 0.5%, p = 0.023), cardiac mortality (11.3%, vs. 3.9%, p = 0.022) and MACCE (33.8%, vs. 19.5%, p = 0.014); female sex was a significant predictor of MACCE in the univariate analysis (HR 1.86, 95%CI 1.12-3.09, p = 0.014); and the cumulative incidence of MACCE was higher in female patients (p = 0.014). After the adjustment, the predictive effect of female sex became non-significant (HR 1.60, 95%CI 0.94-2.73, p = 0.083), while there was no difference in the cumulative incidence of MACCE among the propensity score matched cohort (p = 0.177). Female NSTE-ACS patients have worse long-term outcomes compared to their male counterparts. However, the differences disappear after adjustment and propensity score matching. Continuing efforts and health measures are required to alleviate any sex-based differences in the NSTE-ACS population.

Keywords: long-term follow-up; non-ST-elevation acute coronary syndrome; sex.

Figure 1

Adverse events during the study period. Legend: MACCE, major adverse cardiovascular and cerebrovascular events (composite of cardiac mortality, ischemic stroke, urgent coronary revascularization and nonfatal myocardial infarction).

Figure 2

Hazard ratios (HR) of MACCE for different predictors: (A) Unadjusted rates; (B) Adjusted rates. * Multivariate Cox regression model-reference groups for categorical variables: male sex; no diabetes mellitus. Legend: MACCE, major adverse cardiovascular and cerebrovascular events (composite of cardiac mortality, ischemic stroke, urgent coronary revascularization and nonfatal myocardial infarction); LVEF, left ventricular ejection fraction; eGFR, estimated glomerular filtration rate; BMI, body mass index; RBC, red blood cells.

Figure 3

Event-free survival for MACCE according to sex. Legend: MACCE, major adverse cardiovascular and cerebrovascular events (composite of cardiac mortality, ischemic stroke, urgent coronary revascularization and nonfatal myocardial infarction).

Figure 4

Event-free survival for MACCE according to sex in the propensity score matched cohort. Propensity score matching analysis with a nearest neighbor matching algorithm for age, BMI and eGFR (1:1 allocation and a caliper of 0.01). Legend: MACCE, major adverse cardiovascular and cerebrovascular events (composite of cardiac mortality, ischemic stroke, urgent coronary revascularization and nonfatal myocardial infarction).

Figure 5

Receiver operating characteristic of predicting MACCE for GRACE score in different sex groups. Legend: MACCE, major adverse cardiovascular and cerebrovascular events (composite of cardiac mortality, ischemic stroke, urgent coronary revascularization and nonfatal myocardial infarction); GRACE, Global Registry of Acute Coronary Events.