AIMS: Implantable cardioverter-defibrillator (ICD) implantation reduce the risk of sudden cardiac death, but not all-cause death in patients with non-ischaemic systolic heart failure (HF). Whether co-existence of diabetes affects ICD treatment effects is unclear.

METHODS AND RESULTS: We examined the effect of ICD implantation on risk of all-cause death, cardiovascular death, and sudden cardiac death (SCD) according to diabetes status at baseline in the Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischaemic Systolic Heart Failure on Mortality (DANISH) trial. Outcomes were analysed by use of cumulative incidence curves and Cox regressions models. Of the 1116 patients enrolled, 211 (19%) had diabetes at baseline. Patients with diabetes were more obese, had worse kidney function and more were in New York Heart Association Class III/IV. The risk of device infections and other complications in the ICD group was similar among patients with and without diabetes (6.1% vs. 4.6% P = 0.54). Irrespective of treatment group, diabetes was associated with higher risk of all-cause death, cardiovascular death, and SCD. The treatment effect of ICD in patients with diabetes vs. patients without diabetes was hazard ratio (HR) = 0.92 (0.57-1.50) vs. HR = 0.85 (0.63-1.13); Pinteraction = 0.60 for all-cause mortality, HR = 0.99 (0.58-1.70) vs. HR = 0.70 (0.48-1.01); Pinteraction = 0.25 for cardiovascular death, and HR = 0.81 (0.35-1.88) vs. HR = 0.40 (0.22-0.76); Pinteraction = 0.16 for sudden cardiac death.

CONCLUSION: Among patients with non-ischaemic systolic HF, diabetes was associated with higher incidence of all-cause mortality, primarily driven by cardiovascular mortality including SCD. Treatment effect of ICD therapy was not significantly modified by diabetes which might be due to lack of power.