Impact of diabetes mellitus on long-term survival in patients with congestive heart failure

AIMS: To test the hypothesis that diabetic status may be used as a prognostic indicator in heart failure (HF) patients. METHODS AND RESULTS: We studied 1246 consecutive patients with left ventricular dysfunction. All patients had a cardiopulmonary exercise test and an echocardiogram. Cardiac catheterisation was systematically performed to define HF aetiology. Twenty-two percent of the patients were diabetic (hypoglycaemic drugs or fasting blood glucose >126 mg/dL); in diabetic patients, HF aetiology was ischaemic in 58% vs. 40% in non-diabetic patients ( p 0.01). Diabetes mellitus was an independent predictor of cardiovascular mortality in ischaemic patients (HR=1.54 1.13; 2.09; P = 0.006) but not in non-ischaemic patients (HR=0.65 0.39; 1.07;p = 0.09). When diabetic patients were defined as patients receiving hypoglycaemic drugs at baseline, diabetes mellitus remained an independent predictor of cardiovascular mortality in ischaemic patients (HR=1.43 1.03; 1.98; p = 0.03) while diabetes mellitus was associated with a statistically significant decrease in cardiovascular mortality in non-ischaemic patients (HR=0.46 0.23; 0.88; p = 0.02). CONCLUSION: The prognostic impact of diabetes mellitus in HF patients is markedly influenced by the underlying aetiology and is particularly deleterious in those with ischaemic cardiomyopathy.