HbA1c and heart failure risk among diabetic patients.

Abstract

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. 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. 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. We measured incident HF until May 31, 2012. 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%). The current study suggests a graded positive association of HbA1c with the risk of HF among both African American and white patients with diabetes.