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Original Investigation
June 10, 2019

Risk of Hospitalization for Serious Adverse Gastrointestinal Events Associated With Sodium Polystyrene Sulfonate Use in Patients of Advanced Age

Author Affiliations
  • 1Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
  • 2Institute for Clinical Evaluative Sciences (ICES), Toronto, Ontario, Canada
  • 3Division of Nephrology, Department of Medicine, Health Sciences Centre, London, Ontario, Canada
  • 4Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
  • 5Division of Nephrology, Department of Medicine, St Michael’s Hospital, Toronto, Ontario, Canada
  • 6Division of Nephrology, Department of Medicine, Seven Oaks Hospital, Winnipeg, Manitoba, Canada
  • 7Division of Nephrology, Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada
JAMA Intern Med. 2019;179(8):1025-1033. doi:10.1001/jamainternmed.2019.0631
Key Points

Question  Is the use of sodium polystyrene sulfonate associated with a higher risk of hospitalization for adverse gastrointestinal events?

Findings  In this population-level cohort study of 20 020 matched individuals, sodium polystyrene sulfonate use was associated with a 1.9-fold higher risk of hospitalization within 30 days of initial prescription for adverse gastrointestinal events compared with nonuse.

Meaning  The use of sodium polystyrene sulfonate was associated with a high risk of hospitalization for serious adverse gastrointestinal events.


Importance  Sodium polystyrene sulfonate is commonly prescribed for the treatment of hyperkalemia. Case reports of intestinal injury after administration of sodium polystyrene sulfonate with sorbitol resulted in a US Food and Drug Administration warning and discontinuation of combined 70% sorbitol–sodium polystyrene sulfonate formulations. There are ongoing concerns about the gastrointestinal (GI) safety of sodium polystyrene sulfonate use.

Objective  To assess the risk of hospitalization for adverse GI events associated with sodium polystyrene sulfonate use in patients of advanced age.

Design, Setting, and Participants  Population-based, retrospective matched cohort study of eligible adults of advanced age (≥66 years) dispensed sodium polystyrene sulfonate from April 1, 2003, to September 30, 2015, in Ontario, Canada, with maximum follow-up to March 31, 2016. Initial data analysis was conducted from August 1, 2018, to October 3, 2018; revision analysis was conducted from February 25, 2019, to April 2, 2019. Cox proportional hazards regression models were used to examine the association of sodium polystyrene sulfonate use with a composite of GI adverse events compared with nonuse that was matched via a high-dimensional propensity score. Additional analyses were limited to a subpopulation with baseline laboratory values of estimated glomerular filtration rate and serum potassium level.

Exposure  Dispensed sodium polystyrene sulfonate in an outpatient setting.

Main Outcomes and Measures  The primary outcome was a composite of adverse GI events (hospitalization or emergency department visit with intestinal ischemia/thrombosis, GI ulceration/perforation, or resection/ostomy) within 30 days of initial sodium polystyrene sulfonate prescription.

Results  From a total of 1 853 866 eligible adults, 27 704 individuals were dispensed sodium polystyrene sulfonate (mean [SD] age, 78.5 [7.7] years; 54.7% male), and 20 020 sodium polystyrene sulfonate users were matched to 20 020 nonusers. Sodium polystyrene sulfonate use compared with nonuse was associated with a higher risk of an adverse GI event over the following 30 days (37 events [0.2%]; incidence rate, 22.97 per 1000 person-years vs 18 events [0.1%]; incidence rate, 11.01 per 1000 person-years) (hazard ratio, 1.94; 95% CI, 1.10-3.41). Results were consistent in additional analyses, including the subpopulation with baseline laboratory values (hazard ratio, 2.91; 95% CI, 1.38-6.12), and intestinal ischemia/thrombosis was the most common type of GI injury.

Conclusions and Relevance  The use of sodium polystyrene sulfonate is associated with a higher risk of hospitalization for serious adverse GI events. These findings require confirmation and suggest caution with the ongoing use of sodium polystyrene sulfonate.

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