Sodium polystyrene sulfonate versus sodium zirconium cyclosilicate for the treatment of hyperkalemia in the emergency department.

BACKGROUND: Hyperkalemia accounts for over 800,000 emergency department (ED) visits in the United States each year, and has been associated with significant morbidity and mortality likely due to fatal cardiac dysrhythmias. Previous studies have demonstrated reductions in mortality when potassium levels are normalized in the ED. Cation exchange resins, such as sodium polystyrene sulfonate (SPS) and sodium zirconium cyclosilicate (SZC), may be administered as a means of definitively eliminating potassium from the body. This practice is based on physician preference and is not supported by high quality data. Two studies evaluating the use of cation exchange resins versus standard treatment in the ED demonstrated reductions in serum potassium levels within two hours of administration; however, there have been no published studies investigating these agents in a head-to-head comparison. OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of SPS versus SZC in lowering serum potassium in patients presenting to the ED with hyperkalemia. METHODS: This was an institutional review board-approved, retrospective cohort study conducted at a single-site ED. All patients who received medications under the "ED Hyperkalemia Treatment" order set between August 26, 2019 and May 13, 2021 were eligible for inclusion. The primary outcome was the change in serum potassium from baseline to first repeat level following SPS or SZC administration in the ED. RESULTS: A total of 885 patients were screened with 54 patients in the SPS group and 51 patients in the SZC group included in the final analyses. The mean change in serum potassium from baseline to first repeat level following administration of the cation exchange resin was -1.1 mEq/L for both groups. CONCLUSION: Administration of SPS or SZC for the treatment of hyperkalemia in the ED resulted in similar reductions in serum potassium.