Heart failure severity, as determined by loop diuretic dosages, predicts the risk of developing diabetes after myocardial infarction: a nationwide cohort study

Heart failure (HF) is associated with increased insulin resistance, but the consequences of HF for development of diabetes are not well studied. The aim of the present study was to investigate the relationship between HF severity and risk of developing diabetes in a nationwide cohort of patients with myocardial infarction (MI). Patients discharged from first-time MI during 1997-2006 and not previously treated with glucose-lowering medications (GLM) or loop diuretics were identified from Danish nationwide registers. Heart failure severity was determined by loop diuretic dosage after discharge. Patients were followed until first claimed prescription of GLM, death, or until the end of 2006. The cohort comprised 50 874 patients. A total of 3006 (6%) had mild (loop-diuretic dosage < 40 mg/day), 5383 (11%) moderate (> 40-120 mg/day), and 1127 (2%) severe (> 120 mg/day) HF. During follow-up, 2531 (5%) patients developed diabetes. Increasing HF severity was associated with increased risk of diabetes, but the use of renin-angiotensin system inhibitors (RASi) attenuated the risk (P-value for interaction between the HF group and RASi < 0.05). Compared with no HF, the adjusted hazard ratios (95% confidence interval) for the development of diabetes were 1.34 (1.11-1.63), 1.63 (1.40-1.90), and 1.68 (1.25-2.25) for mild, moderate, and severe HF with RASi treatment; and 1.45 (1.13-1.88), 1.90 (1.56-2.33), and 3.02 (2.01-4.54) for mild, moderate, and severe HF without RASi treatment. Heart failure predicts the development of diabetes in a severity-dependent manner among patients with MI. Focus on increased predisposition to diabetes is warranted and needs further investigations.