HbA1c and Heart Failure Risk Among Diabetic Patients

Context: Diabetes is an independent risk factor for heart failure (HF); however, it is not known whether tight glycemic control can reduce the occurrence of HF among diabetic patients. Objective: The aim of the study was to investigate the race-specific association of different levels of glycosylated hemoglobin (HbA1c) with the risk of HF among patients with diabetes. Design, Setting, and Participants: We prospectively investigated the race-specific association of different levels of HbA1c at baseline and during an average of 6.5 years of follow-up with incident HF risk among 17 181 African American and 12 446 white diabetic patients within the Louisiana State University Hospital System. Main Outcome Measure: We measured incident HF until May 31, 2012. Results: During follow-up, 5089 HF incident cases were identified. The multivariable-adjusted hazard ratios of HF associated with different levels of HbA1c at baseline (<6.0% [ reference group], 6.0-6.9%, 7.0-7.9%, 8.0-8.9%, 9.0-9.9%, and >= 10.0%,) were 1.00, 1.02(95% confidence interval, 0.91-1.15), 1.21 (1.05-1.38), 1.29 (1.12-1.50), 1.37 (1.17-1.61), and 1.49 (1.31-1.69) (P trend < .001) for African American diabetic patients, and 1.00, 1.09 (0.96-1.22), 1.09 (0.95-1.26), 1.43 (1.22-1.67), 1.49 (1.25-1.77), and 1.61 (1.38-1.87) (P trend <.001) for white diabetic patients, respectively. This graded positive association was also present in diabetic patients with and without glucose-lowering agent treatment; in diabetic patients with different age, gender, and smoking status; and in incident HF defined as systolic HF (ejection fraction <= 40%) and HF with a preserved ejection fraction (ejection fraction >40%). Conclusions: The current study suggests a graded positive association of HbA1c with the risk of HF among both African American and white patients with diabetes.