Abstract Body (Do not enter title and authors here):
Background: Despite well-known morbidity and mortality benefits, implementation of guideline-directed medical therapy (GDMT) for HFrEF patients remains suboptimal. Understanding the center-level variation in observed-to-expected GDMT prescribing could support targeted improvement initiatives.

Hypothesis: The risk-adjusted observed to expected (O/E) ratio for GDMT prescribing would vary between hospitals and be associated with mortality and readmissions.

Methods: This cohort study included 100% of Medicare fee-for-service beneficiaries admitted for HFrEF and discharged between Jan 2009 and Dec 2017. Patients were excluded if they were readmitted or died within 60 days of discharge. The primary outcomes were: (1) prescription filling of ≥2 of 3 classes of GDMT (proposed quality measure of GDMT; SGLT2i not yet approved for HFrEF) within 60 days and (2) composite endpoint of death and readmission within 61-120 days post-discharge. The exposures of interest were: (1) center O/E GDMT prescription ratios to evaluate interhospital hospital variability and (2) GDMT quality measure prescription. Risk adjustment was performed via logistic regression, conditioning on demographics, comorbidities, neighborhood distress score, and pre-admission medication utilization.

Results: In total, 296,900 patients were treated at 1,917 hospitals. Patients had a mean (SD) age of 77 (12) years and were 47.0% female (n=139,398). BB, ACE/ARB, and MRA were filled by 56.5%, 48.5%, and 21.2% of patients, respectively. In total, 42% were prescribed and filled ≥2 GDMT classes. Interhospital variability existed in O/E GDMT prescription (Figure). The adjusted difference in GDMT quality metric prescribing was 23.2% between top and bottom quartile hospitals (52.6% and 29.5%). GDMT prescription was associated with a 5.98% (95% CI -5.5 - -6.46%) lower probability of risk-adjusted death or readmission per patient in the subsequent two months.

Conclusions: Large-scale interhospital variability exists in GDMT prescribing for HFrEF patients. While optimal GDMT is indicated for all HFrEF patients, assessing center-level O/E GDMT prescribing enables comparisons against achievable performance benchmarks and should be considered a potential quality indicator.