Effect of cardiac resynchronization on morbidity and mortality of diabetic patients with severe heart failure.

D iabetes is a well-known and important risk factor for heart disease, including heart failure (1–4). Despite improvements in pharmacologic treatment, many patients with heart failure have severe and persistent symptoms, and their prognosis remains poor (5,6). While most recent data indicate a higher mortality rate in diabetic patients with heart failure compared with nondiabetic patients (7–9), it is unresolved whether this effect might be limited to patients with ischemic heart disease and/or patients on insulin therapy (10–13). Cardiac resynchronization therapy (CRT) reduces symptoms and improves left ventricular function and prognosis in many patients with moderate-to-severe heart failure due to systolic dysfunction and cardiac dyssynchrony (14–19). The pathophysiology underlying heart failure in diabetic patients differs from that in nondiabetic patients and is generally considered more progressive. Thus, direct and indirect effects of diabetes on myopathic mechanisms might influence the response of heart failure patients to CRT. We conducted an analysis of the 813 participants of the Cardiac Resynchronisation in Heart Failure (CARE-HF) trial to determine the effect of CRT on the risk of complications and death in diabetic compared with nondiabetic heart failure patients. We also tested the hypothesis that diabetes has a prognostic impact in patients with heart failure.