The Association of Digital Health Application Use With Heart Failure Care and Outcomes: Insights From CONNECT-HF

•Use of evidenced-based practices and achievement of target guideline-directed medical therapy in eligible patients with heart failure with reduced ejection fraction (HfrEF) remains relatively rare, particularly during and immediately posthospitalization for HF. Nearly 1 in 4 patients with HFrEF who are hospitalized for HF are at risk of death or rehospitalization within 30 days after discharge.•Digital tools, including mobile applications focused on HF self-care, may potentially improve quality of care for HFrEF and downstream clinical outcomes.•Large randomized clinical trials are needed to examine digital health interventions and associated quality of care and clinical outcomes. These trials may be challenging to execute without identifying key system-level and patient-level barriers that limit patient engagement through mobile health applications. It is unknown whether digital applications can improve guideline-directed medical therapy (GDMT) and outcomes in heart failure with reduced ejection fraction (HFrEF). Care Optimization Through Patient and Hospital Engagement Clinical Trial for Heart Failure trial (CONNECT-HF) included an optional, prospective ancillary study of a mobile health application among patients hospitalized due to HFrEF. Digital users were matched to nonusers from the usual-care group. Coprimary outcomes included change in opportunity-based composite HF quality scores and HF rehospitalization or all-cause mortality. Among 2431 patients offered digital applications across the United States, 1526 (63%) had limited digital access or insufficient data, 425 (17%) were digital users, and 480 (20%) declined use. Digital users were similar in age to those who declined use (mean 58 vs 60 years; P = 0.031). Digital users (n = 368) vs matched nonusers (n = 368) had improved composite HF quality scores (48.0% vs 43.6%; + 4.76% [3.27–6.24]; P = 0.001) and composite clinical outcomes (33.0% vs 39.6%; HR 0.76 [0.59–0.97]; P = 0.027). Among participants in the CONNECT-HF trial, use of digital applications was modest but was associated with higher HF quality-of-care scores, including use of GDMT and better clinical outcomes. Although cause and effect cannot be determined from this study, the application of technology to guide GDMT use and dosing among patients with HFrEF warrants further investigation. Digital applications for treatment of HF in the CONNECT-HF Digital Ancillary study. Use of digital applications in HFrEF following a hospitalization f