Hyperkalemia and risk of chronic kidney disease progression: A propensity score matched analysis.

Background: Hyperkalemia is a known complication of chronic kidney disease (CKD); however, it is not known whether hyperkalemia directly contributes to CKD progression and the risk of death. Clarifying the extent to which hyperkalemia is associated with CKD progression and mortality can inform clinical practice and guide future research. The objective of this study was to quantify the risks of CKD progression and mortality associated with hyperkalemia in patients with stages 3b/4 CKD.

Methods: This was a real-world, exact and propensity score-matched, observational cohort study using data (January 2016-December 2021) from Optum's deidentified Market Clarity Data, a large US integrated insurance claims/electronic medical record database. The study included matched adult patients with stages 3b/4 CKD with and without hyperkalemia, not regularly treated with an intestinal potassium (K+) binder. Measured outcomes were CKD progression and all-cause mortality. CKD progression was defined as diagnosis of CKD stage 4 (if stage 3b at index), CKD stage 5 or kidney failure, or receipt of dialysis or kidney transplantation.

Results: After matching, there were 6,619 patients in each of the hyperkalemia and non-hyperkalemia cohorts, with a mean (standard deviation) follow-up time of 2.12 (1.42) years. Use of any renin-angiotensin-aldosterone system inhibitors (RAASi) during baseline was common (75.9%) and most patients had CKD stage 3b (71.2%). Patients with hyperkalemia had a 1.60-fold (95% confidence interval [CI] 1.50, 1.71) higher risk of CKD progression and a 1.09-fold (1.02, 1.16) higher risk of all-cause mortality relative to patients without hyperkalemia. Relative risks of CKD progression associated with hyperkalemia were similar within the subset of patients receiving RAASi and across CKD stages, and when alternative definitions of CKD progression were used.

Conclusions: Patients with CKD stages 3b/4 and hyperkalemia experienced significantly higher risks of CKD progression and all-cause mortality than propensity score-matched patients without hyperkalemia.