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 < 0.0001). Clinical follow-up (median 1200 days) was obtained for 1241 patients. There was a statistically significant effect of diabetes mellitus on cardiac survival that differed according to HF aetiology (interaction 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.