To assess trends in guideline-directed medical therapy, implantable cardioverter-defibrillator (ICD) use, and risk-adjusted mortality among patients with recent-onset HFrEF.This research prospectively examined patients with recent-onset HFrEF diagnosed at US Department of Veterans Affairs (VA) health care system facilities from July 1, 2013, through June 30, 2019. Those who had undergone heart transplantation or used a ventricular assist device were excluded. After adjusting for patient characteristics at the beginning of treatment, adjusted mortality was calculated. The researchers sought to differentiate in treatment rates and risk-adjusted mortality across 3 time periods (period 1: July 1, 2013, to June 30, 2015; period 2: July 1, 2015, to June 30, 2017; and period 3: July 1, 2017, to June 30, 2019) as well as variation among VA facilities. The final group comprised 144,074 eligible people who had HFrEF diagnosed between July 1, 2013, and June 30, 2019. The average age was 71.0 (11.4) years, with the majority of participants being male (140 765 [97.7%]). Overall, over time, medical therapy rates changed little, with the usage of a β-blocker recommended by the guideline increasing from 64.2% in 2013 to 72.0% in 2019. The proportion of patients receiving mineralocorticoid receptor antagonist therapy increased from 23.9% in 2013 to 26.9% in 2019, with hydralazine plus nitrate treatment constant at 24.2%. Although the cost of ARNI therapy has risen since its introduction in 2015, it currently stands at 22.6%. Mortality decreased over the research period, from 19.9% (95% CI, 19.6%-20.2%) in July 1, 2013, to 18.4% (95%, 18.0%-18.7%) in July 1, 2017, and to 18.1%. According to the research, there was little change in the therapy recommended by the guideline and mortality rates among patients with recent-onset HFrEF between 2013 and 2019. New methods to increase the use of HFrEF therapy were required, leading to greater mortality reductions.