Long-Term Follow-Up of DANISH (The Danish Study to Assess the Efficacy of ICDs in Patients With Nonischemic Systolic Heart Failure on Mortality)
Authors: Yafasova Adelina , Butt Jawad H. , Elming Marie B. , Nielsen Jens C. , Haarbo Jens , Videbæk Lars , Olesen Line L. , Steffensen Flemming H. , Bruun Niels E. , Eiskjær Hans , Brandes Axel , Thøgersen Anna M. , Egstrup Kenneth , Gustafsson Finn , Hassager Christian , Svendsen Jesper H. , Høfsten Dan E. , Torp-Pedersen Christian , Pehrson Steen , Thune Jens J. , Køber Lars 
Published: December 2021

Background:
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.

Methods:
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).

Results:

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];
P
= 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];
P
= 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];
P
= 0.75). Cardiovascular death showed similar trends (overall, 147/556 [26%] versus 164/560 [29%]; HR, 0.87 [95% CI, 0.70–1.09];
P
= 0.20; ≤70 years, 87/389 [22%] versus 122/440 [28%]; HR, 0.75 [95% CI, 0.57–0.98];
P
= 0.04; >70 years, 60/167 [36%] versus 42/120 [35%]; HR, 0.97 [95% CI, 0.65–1.45];
P
= 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];
P
= 0.02) and in patients ≤70 years (19/389 [5%] versus 49/440 [11%]; HR, 0.42 [95% CI, 0.24–0.71];
P
= 0.0008), but not in patients >70 years (16/167 [10%] versus 8/120 [7%]; HR, 1.34 [95% CI, 0.56–3.19];
P
= 0.39).

Conclusions:
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, cardiovascular death, and sudden cardiovascular death.

Registration:

URL:
https://www.clinicaltrials.gov
; Unique identifier: NCT00542945.