Sex Differences in Clinical Characteristics, Psychosocial Factors, and Outcomes Among Patients With Stable Coronary Heart Disease: Insights from the STABILITY (Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy) Trial

BACKGROUND: Greater understanding of differences between men and women with coronary heart disease is needed. METHODS AND RESULTS: In this post hoc analysis of the STABILITY (Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy) trial, we described psychosocial factors, treatments, and outcomes of men versus women with stable coronary heart disease and explored the association of sex with psychosocial characteristics and cardiovascular risk. Cox proportional hazards models were used to assess the relationship between sex and outcomes. Interactions among sex, psychosocial factors, and the composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke were tested. Of 15 828 patients, 2967 (19%) were women. Among women, 21.2% felt often or always stressed at home (versus 9.8% of men), and 19.2% felt often or always sad or depressed (versus 10.1% of men; all P<0.0001). The median duration of follow-up was 3.7 years (25th-75th percentiles: 3.5-3.8 years). Use of evidence-based medications for coronary heart disease at baseline and 24 months was similar between sexes, as were event rates for all outcomes analyzed. In the multivariable model including psychosocial measures, female sex was associated with lower cardiovascular risk. There was a statistically significant interaction (P=0.03) such that the lower risk in women varied by depressive symptom frequency, whereby women who were more depressed had a risk similar to men. CONCLUSIONS: Female sex was independently associated with better long-term clinical outcomes, although this was modified by frequency of depressive symptoms. This suggests that emotional state may be an important target for improving outcomes in patients with coronary heart disease, specifically in women. CLINICAL TRIAL REGISTRATION: STABILITY ClinicalTrials.gov number (NCT00799903).