Long-Term Follow-Up of DANISH (The Danish Study to Assess the Efficacy of ICDs in Patients With Nonischemic Systolic Heart Failure on Mortality)

DANISH (The Danish Study to Assess the Efficacy of Implantable Cardioverter Defibrillators [ICDs] in Patients With Nonischemic Systolic Heart Failure on Mortality) found that primary-prevention ICD implantation was not associated with an overall survival benefit in patients with nonischemic systolic heart failure during a median follow-up of 5.6 years, although there was a beneficial effect on all-cause mortality in patients ≤70 years. This study presents an additional 4 years of follow-up data from DANISH. In DANISH, 556 patients with nonischemic systolic heart failure were randomized to receive an ICD and 560 to receive usual clinical care and followed until June 30, 2016. In this long-term follow-up study, patients were followed until May 18, 2020. Analyses were conducted for the overall population and according to age (≤70 and >70 years). During a median follow-up of 9.5 years (25th-75th percentile, 7.9-10.9 years), 208/556 patients (37%) in the ICD group and 226/560 patients (40%) in the control group died. Compared with the control group, the ICD group did not have significantly lower all-cause mortality (hazard ratio [HR] 0.89, [95% CI, 0.74-1.08]; = 0.24). In patients ≤70 years (n = 829), all-cause mortality was lower in the ICD group than the control group (117/389 [30%] versus 158/440 [36%]; HR, 0.78 [95% CI, 0.61-0.99]; = 0.04), whereas in patients >70 years (n = 287), all-cause mortality was not significantly different between the ICD and control group (91/167 [54%] versus 68/120 [57%]; HR, 0.92 [95% CI, 0.67-1.28]; = 0.75). Cardiovascular death showed similar trends (overall, 147/556 [26%] versus 164/560 [29%]; HR, 0.87 [95% CI, 0.70-1.09]; = 0.20; ≤70 years, 87/389 [22%] versus 122/440 [28%]; HR, 0.75 [95% CI, 0.57-0.98]; = 0.04; >70 years, 60/167 [36%] versus 42/120 [35%]; HR, 0.97 [95% CI, 0.65-1.45]; = 0.91). The ICD group had a significantly lower incidence of sudden cardiovascular death in the overall population (35/556 [6%] versus 57/560 [10%]; HR, 0.60 [95% CI, 0.40-0.92]; = 0.02) and in patients ≤70 years (19/389 [5%] versus 49/440 [11%]; HR, 0.42 [95% CI, 0.24-0.71]; = 0.0008), but not in patients >70 years (16/167 [10%] versus 8/120 [7%]; HR, 1.34 [95% CI, 0.56-3.19]; = 0.39). During a median follow-up of 9.5 years, ICD implantation did not provide an overall survival benefit in patients with nonischemic systolic heart failure. In patients ≤70 years, ICD implantation was associated with a lower incidence of all-cause mortality, card