Efficacy of an implantable cardioverter-defibrillator in patients with diabetes and heart failure and reduced ejection fraction

Background The effect of implantable cardioverter-defibrillator (ICD) therapy in patients with heart failure with reduced ejection fraction (HFrEF) and diabetes is not fully elucidated. Methods We examined the effect of ICD therapy on sudden cardiac death, cardiovascular death and all-cause mortality, according to diabetes status at baseline in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT). The outcomes were analyzed by use of cumulative incidence curves and Cox regressions models. Results Of the 1676 patients randomized to an ICD or placebo, 540 (32%) had diabetes at baseline. Patients with diabetes were slightly older (61 vs 58 years) and were more often in NYHA class III (37% vs 28%). ICD therapy did not reduce the risk of sudden cardiac death in HFrEF patients with diabetes (HR=0.85; 95% CI 0.52-1.40); even though these patients had a higher risk of sudden cardiac death compared to patients without diabetes (HR=1.73 95% CI 1.22-2.47). By contrast, ICD therapy did reduce sudden cardiac death in HFrEF patients without diabetes (HR=0.26; 95% CI 0.15-0.46); P-interaction=0.002. The findings for cardiovascular and all-cause death were similar. Conclusion ICD therapy did not reduce the risk of sudden cardiac death (or, as a consequence, all-cause death) in HFrEF patients with diabetes. Conversely, an ICD reduced the risk of sudden death in patients without diabetes, irrespective of etiology.