Characteristics, treatment, and outcomes of early vs. late enrollees of the STRONG-HF trial

Background The STRONG-HF trial showed that high-intensity care (HIC) consisting of rapid up-titration of guideline-directed medical therapy (GDMT) and close follow-up reduced all-cause death or heart failure (HF) readmission at 180 days compared to usual care (UC). We hypothesized that significant differences in patient characteristics, management, and outcomes over the enrolment period may exist. Methods Two groups of the 1,078 patients enrolled in STRONG-HF were created according to the order of enrolment within center. The early group consisted of the first 10 patients enrolled at each center (N = 342) and the late group consisted of the following patients (N = 736). Results Late enrollees were younger, had more frequently reduced ejection fraction, slightly lower NT-proBNP and creatinine levels compared with early enrollees. The primary outcome occurred less frequently in early compared to late enrollees (15% vs. 21%, aHR 0.65, 95% CI 0.42-0.99, P = .044). No treatment-by-enrolment interaction was seen in respect to the average percentage of optimal dose of GDMT after randomization, which was consistently higher in early and late patients randomized to HIC compared to UC. The higher use of renin-angiotensin-inhibitors in the HIC arm was more pronounced in the late enrollees both after randomization (interaction-P = .013) and at 90 days (interaction-P < .001). No interaction was observed for safety events. Patients randomized late to UC displayed a trend toward more severe outcomes (26% vs. 16%, P = .10), but the efficacy of HIC showed no interaction with the enrolment group (aHR 0.77, 95% CI 0.35-1.67 in early and 0.58, 95% CI 0.40-0.83 in late enrollees, adjusted interaction-P = .51) with similar outcomes in the HIC arm in late and early enrollees (16% vs. 13%, P = .73). Conclusions Late enrollees have different clinical characteristics and higher event rates compared to early enrollees. GDMT implementation in the HIC arm robustly achieved similar doses with consistent efficacy in early and late enrollees, mitigating the higher risk of adverse outcome in late enrollees. Trial registration ClinicalTrials.gov Identifier: NCT03412201.