Report Rates of Spironolactone Initiation and Subsequent Hyperkalemia Hospitalizations in Patients with Heart Failure with Preserved Ejection Fraction Following the TOPCAT trial: A Cohort Study of Medicare Beneficiaries

Background: The impact of the TOPCAT trial publication on spironolactone initiation and subsequent hospitalizations for hyperkalemia among patients with heart failure with preserved ejection fraction (HFpEF) has not been evaluated empirically. Methods and Results: We designed a cohort study using US Medicare fee-for-service data. Annual cohorts of patients with HFpEF from 2013 to 2018 were identified based on a validated claims-based phenotyping model. We determined spironolactone initiation in each annual cohort overall and within subgroups with hyperkalemia risk factors of baseline renin-angiotensin system inhibitors use, chronic kidney disease, and diabetes. We reported incidence rates of hospitalization for hyperkalemia within 6 months of treatment initiation. A total of 621,171 patients with HFpEF (mean age 80 +/- 8 years, 62.9% female) were included. We identified 40,241 initiations of spironolactone with initiation rate/100 person-years of 16.8 (95% confidence interval [CI] 16.4-17.1) in 2013 and increasing to 19.9 (95% CI 19.4-20.5) in 2018. Among initiators, we identified a total of 164 hyperkalemia hospitalization with stable incidence rates per 1000 person-years between 2013 (12.0, 95% CI 8.8-16.1) and 2018 (10.6, 95% CI 6.2-17.0). These results were consistent for all subgroups. Conclusions: After the dissemination of TOPCAT findings, we noted a steady increase in the initiation of spironolactone, but not in hyperkalemia hospitalizations.