Sex Differences in the Impact of Coexistent Diabetes on Survival in Patients With Coronary Heart Disease

OBJECTIVE: To evaluate the sex difference in the impact of diabetes on survival in patients with coronary heart disease. RESEARCH DESIGN AND METHODS: Cohort study based on a sample from a hospital registry in Chicago, IL. A total of 974 consecutive patients (585 men and 389 women) with angiographically confirmed coronary artery disease were followed for 4.6 yr. RESULTS: At baseline, 160 men and 155 women had diabetes. The age-adjusted relative risk of death from all causes for patients with diabetes versus patients without diabetes was 0.93 (95% confidence interval 0.65-1.34) in men and 1.99 (95% CI 1.30-3.05) in women. For cardiac death, the corresponding relative risk was 1.00 (95% CI 0.64-1.56) and 1.96 (95% CI 1.19-3.24) in men and women, respectively. Baseline differences in age, hypertension, body mass index, number of diseased vessels, and ejection fraction did not fully explain the excess mortality risk in diabetic women. Excess risk was apparent in both cardiac and noncardiovascular categories. Among nondiabetic patients, the risk of death was significantly lower in women compared with men (multivariate-adjusted relative risk = 0.61, 95% CI 0.41-0.89). However, the mortality risk of diabetic women became similar to men as a whole (relative risk = 1.13, 95% CI 0.80-1.60). CONCLUSIONS: Diabetes confers a substantially higher risk of mortality in women than in men when it occurs in the presence of coronary heart disease.