Discharge Prescription of Renin-Angiotensin System Inhibitors After Hyperkalemia and Its Association With Mortality and Dialysis Outcomes

Background: Medication changes at hospital discharge may influence post-discharge outcomes. Renin-angiotensin system inhibitors (RASi) are frequently discontinued during hospitalization for hyperkalemia; however, guidance regarding discharge prescribing is limited. We evaluated the association between RASi prescription at discharge and post-discharge outcomes in patients hospitalized with hyperkalemia. Methods: In this single-center retrospective cohort study at a large tertiary hospital, adults admitted between 2005 and 2020 with a potassium level > 5.5 mEq/L while receiving chronic RASi therapy were included and followed through 2022. Exposure was defined as prescription versus non-prescription of RASi at discharge. Propensity score matching was used among survivors of the first hospitalization to balance baseline characteristics. Kaplan-Meier and multivariable Cox models were used to assess all-cause mortality and chronic dialysis. Results: Among 12,326 patients with confirmed hyperkalemia, 9,051 survived the index hospitalization; 4,388 were included after matching (2,194 per group). Prescription of RASi at discharge was associated with lower mortality (401 (18.3%) vs 642 (29.3%); hazard ratio (HR), 0.62; 95% confidence interval (CI), 0.55-0.71) but a higher risk of chronic dialysis initiation (167 (8.2%) vs. 111 (5.7%); HR, 1.57; 95% CI, 1.23-1.99). Conclusions: In patients hospitalized with hyperkalemia, discharge prescription of RASi was associated with lower mortality but a higher incidence of chronic dialysis initiation. Dialysis initiation may reflect both progression of renal disease and longer survival among patients discharged on RASi therapy. Given the observational study design, these findings should be interpreted as associations rather than causal effects and underscore the complex risk-benefit considerations surrounding discharge medication decisions.