Comparison of Sodium Zirconium Cyclosilicate to Calcium Polystyrene Sulfonate for Acute Hyperkalemia Among Hospitalized Elderly Patients

Background Our aim was to investigate the effect of sodium zirconium cyclosilicate (SZC) on acute hyperkalemia in hospitalized elderly patients. Methods A retrospective observational study was conducted. All consecutive patients aged 65 years or older who were hospitalized in our hospital between January 2020 and September 2023 were screened. Patients with serum potassium greater than 5.0 mEq/L and those who were prescribed either SZC or calcium polystyrene sulfonate (CPS) during hospitalization were included. The primary outcome was the change in serum potassium within 24 hours from baseline. Patients who were prescribed SZC and those who were prescribed CPS were compared by the Mann-Whitney test. Results A total of 87 hospitalized elderly patients with acute hyperkalemia were included. The median age of the patients was 81 years (IQR 75 to 86); 64 (73.6%) were men, and 64 (73.6%) had chronic kidney disease. The median serum potassium concentration was 6.0 mEq/L (IQR 5.7 to 6.4). Of those, 53 patients received SZC, and 35 patients received CPS. While SZC reduced the serum potassium concentration from 6.1 mEq/L to 5.0 mEq/L, CPS reduced the potassium concentration from 5.9 mEq/L to 5.3 mEq/L within 24 hours. Compared with CPS, SZC significantly reduced potassium (<i>p</i> = 0.003). Conclusions Compared with CPS, SZC might reduce serum potassium more among hospitalized elderly patients with hyperkalemia. Further studies are warranted to determine the role of SZC for acute hyperkalemia in acute care settings.