Objective: The aims of this study were to update previous estimates of the congestive heart failure (CHF) incidence rate in patients with type 2 diabetes, compare it with an age- and sex-matched nondiabetic group, and describe risk factors for developing CHF in diabetic patients over 6 years of follow-up.
Research design and methods: We performed a retrospective cohort study of 8,231 patients with type 2 diabetes and 8,845 nondiabetic patients of similar age and sex who did not have CHF as of 1 January 1997, following them for up to 72 months to estimate the CHF incidence rate. In the diabetic cohort, we constructed a Cox regression model to identify risk factors for CHF development.
Results: Patients with diabetes were much more likely to develop CHF than patients without diabetes (incidence rate 30.9 vs. 12.4 cases per 1,000 person-years, rate ratio 2.5, 95% CI 2.3-2.7). The difference in CHF development rates between persons with and without diabetes was much greater in younger age-groups. In addition to age and ischemic heart disease, poorer glycemic control (hazard ratio 1.32 per percentage point of HbA(1c)) and greater BMI (1.12 per 2.5 units of BMI) were important predictors of CHF development.
Conclusions: The CHF incidence rate in type 2 diabetes may be much greater than previously believed. Our multivariate results emphasize the importance of controlling modifiable risk factors for CHF, namely hyperglycemia, elevated blood pressure, and obesity. Younger patients may benefit most from risk factor modification.