Risk of Hospitalization for Heart Failure in Patients With Hyperkalemia Treated With Sodium Zirconium Cyclosilicate Versus Patiromer

Background: Sodium zirconium cyclosilicate (SZC) and patiromer were recently approved to treat hyperkalemia. Whether the initiation of SZC is associated with an increased risk of hospitalization for heart failure (HHF) compared with patiromer in routine practice remains unknown. Methods and Results: We conducted a new-user cohort study of nondialysis adults who initiated SZC or patiromer using Optum's de-identified Clinformatics Data Mart Database from May 2018 to September 2020. We performed propensity score matching in a variable ratio to match each SZC initiator with up to 3 patiromer initiators. The primary outcome was HHF. Cox proportional hazards regression models generated hazard ratios with 95% confidence intervals in the propensity score-matched groups. The cohort included 1126 SZC initiators and 2839 propensity score-matched patiromer initiators. The mean age was 72 years old, approximately 30% had a history of HF, and 85% had chronic kidney disease stages 3-5. The SZC group had 88 cases of HHF (incidence rate 35.8 per 100 person-years), and the patiromer group had 245 cases of HHF (incidence rate 25.1 per 100 person-years). The rate of HHF was numerically higher in the SZC initiators than patiromer initiators (hazard ratio 1.22, 95% confidence interval 0.95-1.56), but did not reach statistical significance. Results were consistent across sensitivity and subgroup analyses. Conclusions: The initiation of SZC might be associated with an increased risk of HHF com-pared with patiromer in routine practice. Larger comparative studies are needed to evaluate the safety of SZC in routine practice more precisely.