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Abstract: FR-PO302

The Association of Sodium Polystyrene Sulfate (Kayexelate™) Use and Adverse Gastrointestinal Events

Session Information

Category: Fluid and Electrolytes

  • 902 Fluid and Electrolytes: Clinical

Authors

  • Noel, Ariana, University of Ottawa, Ottawa, Ontario, Canada
  • Petrcich, William, Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada
  • Bota, Sarah E., Institute for Clinical Evaluative Sciences, Ottawa, Ontario, Canada
  • Harel, Ziv, University of Toronto, Toronto, Ontario, Canada
  • Sood, Manish M., Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
Background

Sodium Polystyrene Sulfate (SPS, Kayexelate™) is a commonly prescribed medication for the treatment of hyperkalemia. Case reports implicate the possibility of intestinal injury with SPS with or without sorbitol. In this regard, we set out to assess the risk of GI adverse events (intestinal ischemia, ulceration and perforation, abdominal surgery) with SPS use.

Methods

Population-based, retrospective cohort study of 1,853,866 eligible adults of advanced age (> 66 years) between 1995 and 2015 in Ontario, Canada. A high dimensional propensity score was used to match adults with a SPS prescription to no SPS prescription. The primary outcome was a composite of adverse gastrointestinal outcomes (intestinal ischemia, ulceration/perforation, abdominal survey) within 1-year of initial SPS prescription. Secondary outcomes included each component of the composite primary outcome. Cox proportional hazards were used to examine the association of SPS and a composite of GI adverse events. Additional sensitivity analyses limited to patients with laboratory values (eGFR, serum potassium) and a unrelated dummy outcome (cataracts) were performed. Pre-specificed subgroups of interest were examined using interaction terms.

Results

From 1, 853, 866 eligible adults, 20,020 were prescribed SPS (mean age 78.5 SD 7.7 years, 46% female) and matched. The risk of any adverse GI event was higher with SPS use compared to non-use (n=370 events, HR 1.26 95%CI 1.03-1.55). Among the individual types of GI adverse injury, gastrointestinal ulceration and perforation (HR 1.56 95%CI 1.08-2.25) events were higher with SPS whereas intestinal ischemia and abdominal surgery were similar. Among SPS-users with laboratory values (n= 7557, mean eGFR 44.8 SD 20.3 ml/min/1.73m2, mean serum potassium 5.6 SD 0.7 mEq/L), the risk of any adverse GI event was similarly elevated (HR 1.44 95%CI 1.09-1.90). The findings were consistent after additional adjustment for living in a rural residence or a long-term care home and there was no association with SPS use and the dummy outcome (cataracts). The results were consistent across all prespecified subgroups.

Conclusion

The use of SPS is associated with a higher risk of adverse gastrointestinal events. Our findings suggest caution with the use of SPS and alternative treatments for potassium lowering be considered.

Funding

  • NIDDK Support