Hyperkalemia-Related Discontinuation of Renin-Angiotensin-Aldosterone System Inhibitors and Clinical Outcomes in CKD: A Population-Based Cohort Study.

Rationale & Objective: Renin-angiotensin-aldosterone system (RAAS) inhibitors are evidence-based therapies that slow the progression of chronic kidney disease (CKD) but can cause hyperkalemia. We aimed to evaluate the association of discontinuing RAAS inhibitors after an episode of hyperkalemia and clinical outcomes in patients with CKD.

Study Design: Retrospective cohort study.

Setting & Participants: Adults in Manitoba (7,200) and Ontario (n = 71,290), Canada, with an episode of de novo RAAS inhibitor-related hyperkalemia (serum potassium ≥ 5.5 mmol/L) and CKD.

Exposure: RAAS inhibitor prescription.

Outcome: The primary outcome was all-cause mortality. Secondary outcomes were cardiovascular (CV) mortality, fatal and nonfatal CV events, dialysis initiation, and a negative control outcome (cataract surgery).

Analytical Approach: Cox proportional hazards models examined the association of RAAS inhibitor continuation (vs discontinuation) and outcomes using intention to treat approach. Sensitivity analyses included time-dependent, dose-dependent, and propensity-matched analyses.

Results: The mean potassium and mean estimated glomerular filtration rate were 5.8 mEq/L and 41 mL/min/1.73 m, respectively, in Manitoba; and 5.7 mEq/L and 41 mL/min/1.73 m, respectively, in Ontario. RAAS inhibitor discontinuation was associated with a higher risk of all-cause mortality (Manitoba: HR, 1.32 [95% CI, 1.22-1.41]; Ontario: HR, 1.47 [95% CI, 1.41-1.52]) and CV mortality (Manitoba: HR, 1.28 [95% CI, 1.13-1.44]; and Ontario: HR, 1.32 [95% CI, 1.25-1.39]). RAAS inhibitor discontinuation was associated with an increased risk of dialysis initiation in both cohorts (Manitoba: HR, 1.65 [95% CI, 1.41-1.85]; Ontario: HR, 1.11 [95% CI, 1.08-1.16]).

Limitations: Retrospective study and residual confounding.

Conclusions: RAAS inhibitor discontinuation is associated with higher mortality and CV events compared with continuation among patients with hyperkalemia and CKD. Strategies to maintain RAAS inhibitor treatment after an episode of hyperkalemia may improve clinical outcomes in the CKD population.