Initiation of sodium polystyrene sulphonate (SPS) for the management of hyperkalemia in chronic kidney disease (CKD) is associated with a higher risk of severe gastrointestinal (GI) complications as well as the initiation of GI-related medications, particularly when prescribed at per label doses, according to a study from the Karolinska Institutet in Sweden.

Hyperkalemia is a common and potentially life-threatening complication of advanced CKD. Hyperkalemia treatment generally consists of a reduction of dietary intake, modification of contributing medications and the use of cation-exchange resin such as SPS. Data on SPS safety are scarce and ambiguous. Therefore, researchers set out to systematically examine SPS use and GI safety in a large Swedish representative cohort of nephrologist-referred patients with CKD.

The retrospective cohort study, published in Nephrology, Dialysis, Transplantation, was based on the Swedish Renal Registry (SRR), a nationwide registry of patients on renal replacement therapy or patients with CKD stages 3-5 followed at any nephrology clinic in Sweden. The study is the second largest evaluation to date of SPS use and safety in patients with CKD, according to the authors.

Approximately 19,530 patients in the SRR with an eGRF ≤30 mL/min/1.73 m2 between January 1, 2006, and December 31, 2016, were enrolled in the study. All participants were non-exposed and some of them initiated SPS during follow-up.

Of this cohort, 3690 patients initiated SPS, including 59% who took SPS chronically, or 3 mean dispensations of 450 g each per year.  The other 85% were prescribed lower dosages than specified on the product label.

Approximately 202 severe and 1149 minor GI events were recorded during follow-up, according to the study. Hypertension was the most commonly observed comorbidity (81%), followed by diabetes (40%), coronary artery disease (31%) and congestive heart failure (27%).

SPS initiation was associated with a significant 25% greater risk for severe adverse GI events compared with nonuse in adjusted analyses. Patients taking the per label dose were at higher risk than those taking lower doses: 54% vs 20%.

GI ulcers and perforations were the most common severe event and some patients experienced intestinal ischemia or thrombosis. SPS also was associated with a significant 11% greater risk for minor GI events requiring de novo dispensation of laxatives or antidiarrheal drugs, regardless of dose.

Additionally, the researchers observed a dose-dependent increased incidence of serious GI adverse events for CKD patients initiating SPS therapy. SPS was prescribed as a solo agent and no SPS user took concomitant sorbitol, in accordance with recommendations from the medical agencies.

“Our findings add to previous evidence and provoke concern, suggesting caution in the use of this medication,” the report concluded.

Reference
  1. Laureati P, Xu Y, Trevisan M, et al. Initiation of sodium polystyrene sulphonate and the risk of gastrointestinal adverse events in advanced chronic kidney disease: a nationwide study. Published August 4, 2019. https://academic.oup.com/ndt/advance-article/doi/10.1093/ndt/gfz150/5543535. Accessed November 4, 2019.