Clinical question: What is the risk of intestinal necrosis with sodium polystyrene (SPS) for the treatment of hyperkalemia?
Background: SPS is a medication that has been available for the treatment of hyperkalemia since the 1950s. It is a cation exchange resin that works in the colonic lumen by exchanging potassium for sodium leading to an increase in potassium loss in the stool. Reports of severe gastrointestinal side effects, including intestinal necrosis, have been reported with SPS since the 1970s. This concern has led to the development and approval by the U.S. Food and Drug Administration of two new cation-exchangers for the treatment of hyperkalemia. However, more recent studies examining SPS have shown mixed results on its association with intestinal necrosis.
Study design: Meta-analysis
Setting: Literature search of Cochrane Library, Embase, Medline, Google Scholar, PubMed, Scopus, and Web of Science Core Collection databases
Synopsis: The authors identified six studies (five observational and one randomized, controlled trial) with a total of 26,716 participants that compared SPS treatment with controls. The prevalence of intestinal ischemia in patients treated with SPS was 0.1% (95% confidence interval 0.03%-0.17%). The pooled odds ratio of intestinal necrosis was 1.43 (95% confidence interval 0.39-5.20). Two of the six studies reported rates of intestinal necrosis using survival analysis and had a pooled hazard ratio for intestinal necrosis of 2.00 (95% confidence interval, 0.45-8.78). Overall, there was moderate-high statistical significance for the meta-analysis of intestinal necrosis (Q=18.82; P<0.01; I2=67.8%). And, due to concerns with the risk of bias, inconsistency, imprecision, effect size, and direction of confounding in the individual studies, the strength of evidence for associations between SPS and intestinal necrosis was very low.
Bottom Line: The overall risk of intestinal necrosis with SPS is quite low, therefore SPS may be used safely as opposed to the newer, costly cation-exchange resins that are currently on the market for the treatment of hyperkalemia.
Citation: Holleck JL, et al. Risk of intestinal necrosis with sodium polystyrene sulfonate: a systematic review and meta-analysis. J Hosp Med. 2021;16(8):489-494. doi:10.12788/jhm.3655.
Dr. Lippert is an assistant professor of internal medicine at Wake Forest School of Medicine, Winston-Salem, N.C.