Estimated Number Needed to Treat to Avoid a First Hospitalization by Maintaining Instead of Reducing Renin-Angiotensin-Aldosterone System Inhibitor (RAASi) Therapy after Hyperkalemia

BACKGROUND Renin-angiotensin-aldosterone system inhibitor (RAASi) therapy provides cardiorenal protection but is often down-titrated or discontinued following a hyperkalemia episode. This observational study describes the extent of hyperkalemia-related RAASi reduction in patients with chronic kidney disease (CKD) and/or heart failure (HF), and estimates the number needed to treat (NNT) to avoid a first hospitalization if RAASi had been maintained at the prior dose. METHODS Healthcare registers and claims data from Germany, Spain, Sweden, and the UK were used to identify non-dialysis patients with CKD and/or HF who had a hyperkalemia episode while on RAASi. Patients whose RAASi therapy was reduced (down-titrated/discontinued) after the hyperkalemia episode were propensity score (PS)-matched to those with maintained RAASi, and their risks of a hospitalization within 6 months were estimated using the Kaplan-Meier method. Based on the absolute difference in this 6-month risk, the NNT framework was applied to estimate the number of patients who needed to have maintained instead of reduced their RAASi to avoid a first hospitalization during this period. RESULTS Overall, 40,059 patients from Germany, Spain, Sweden, and the UK were included. Presence of CKD at baseline was similar across countries (72%-92%), while HF was less common in Spain (18%) versus other countries (32%-71%). After the hyperkalemia episode, RAASi was reduced in 25%-57% of patients. Following PS matching, the 6-month risk of hospitalization was consistently higher in those with reduced versus maintained RAASi; the absolute risk difference ranged from 2.7% to 7.3%. Applying the NNT framework, these data suggest that a first hospitalization within 6 months could potentially have been avoided if 25 patients had maintained instead of reduced their RAASi. CONCLUSIONS Our findings suggest a potential for avoiding a first hospitalization, even within a short time frame, by increasing adherence to guidelines to maintain instead of reduce RAASi after a hyperkalemia episode.