Efficacy of Sodium Polystyrene Sulfonate in the Treatment of Hyperkaliemia in Pre-dialysis Patients

Overview

The purpose of this trial is to determine if sodium polystyrene sulfonate (SPS) is an effective treatment of mild hyperkalemia in chronic kidney disease patients followed at a pre-dialysis or nephrology outpatient clinic. Subjects will be randomized to one of two treatment arms: 30 g of placebo or SPS to be taken orally once daily for seven days. The change in serum potassium levels will be compared in both treatment groups. The proportion of subjects attaining normokalemia (3.5 to 5.0 mmol/L) after seven days of treatment will also be compared. Finally, side effects will be reported for each treatment arm.

Background Hyperkalemia affects up to 10% of patients suffering from chronic kidney failure and up to 42% of patients with an estimated glomerular filtration rate lower than 20 mL/min/1.73m2. There is currently limited evidence on the use of sodium polystyrene sulfonate for the treatment of mild hyperkalemia. There are even fewer trials supporting its use over several days. To our knowledge, only one other study has evaluated its chronic use in fourteen patients, but hadn't controlled for recent changes in medications. Since its use is associated with adverse events that can considerably affect patients' quality of life, it appears primordial to better assess its place in the treatment of hyperkalemia in pre-dialysis patients. Methods The aim of this trial is to evaluate the use of sodium polystyrene sulfonate in the treatment of mild asymptomatic hyperkalemia in predialysis patients. Participants will be randomized to receive either 30 g of placebo or 30 g of SPS orally once daily for seven days. Serum potassium levels will be assessed at baseline and on the day following the last dose of their treatment. The change in serum potassium levels and the proportion of patients attaining normokalemia will be compared between study groups. The incidence of adverse events (nausea, diarrhea, constipation, electrolyte disorders) will also be reported. Participants will also be asked to fill out a food diary for 3 out of the 7 study days. This diary will be used to estimate each participant's average daily intake of potassium and therefore evaluate the similarity of diets between both intervention arms.