Gender differences in clinical outcomes among diabetic patients hospitalized for cardiovascular disease

Background The risk of incident cardiovascular disease (CVD) has been shown to be greater among diabetic women than men, but gender differences in clinical outcomes among diabetic patients hospitalized with CVD are not established. We aimed to determine if hemoglobin A1c (HbA(1c)) was associated with 30-day and 1-year CVD rehospitalization and total mortality among diabetic patients hospitalized for CVD, overall and by gender. Methods This was a prospective analysis of diabetic patients hospitalized for CVD, enrolled in an National Heart, Lung and Blood Institute-sponsored observational clinical outcomes study (N = 902, 39% female, 53% racial/ ethnic minority, mean age 67 +/- 12 years). Laboratory, rehospitalization, and mortality data were determined by hospital-based electronic medical record. Poor glycemic control was defined as HbA(1c) >= 7%. The association between HbA(1c) and clinical outcomes was evaluated using logistic regression; gender modification was evaluated by interaction terms and stratified models. Results Hemoglobin A1c >= 7% prevalence was 63% (n = 566) and was similar by gender. Hemoglobin A1c >= 7% vs <7% was associated with increased 30-day CVD rehospitalization in univariate (odds ratio [OR] = 1.63, 95% CI 1.05-2.54) and multivariable-adjusted models (OR 1.74, 95% CI 1.06-2.84). There was an interaction between glycemic control and gender for 30-day CVD rehospitalization risk (P = .005). In stratified univariate models, the association was significant among women (OR 4.83, 95% CI 1.84-12.71) but not among men (OR 1.02, 95% CI 0.60-1.71). The multivariate-adjusted risk for HbA(1c) >= 7% versus <7% among women was 8.50 (95% CI 2.31-31.27) and 1.02 (95% CI 0.57-1.80) for men. A trend toward increased 30-day/ 1-year mortality risk was observed for HbA(1c) <6% vs >= 6% for men and women. Conclusions Risk of 30-day CVD rehospitalization was 8.5-fold higher among diabetic women hospitalized for CVD with HbA(1c) >= 7% vs <7%; no association was observed among men. A trend for increased 30-day/ 1-year mortality risk with HbA(1c) <6% deserves further study.