Economic burden of recurrent hyperkalemia in patients with chronic kidney disease.

BACKGROUND

Hyperkalemia is a common complication of chronic kidney disease (CKD) and can become recurrent in half of cases. However, the incremental economic burden associated with recurrent hyperkalemia is unknown.

OBJECTIVE

To evaluate all-cause health care resource utilization (HRU) and medical costs in patients with stage 3/4 CKD with recurrent hyperkalemia vs normokalaemia and vs nonrecurrent hyperkalemia.

METHODS

Data were from Optum's de-identified Market Clarity Data (January 1, 2016, to August 1, 2022). This retrospective observational cohort study compared patients with stage 3/4 CKD with recurrent hyperkalemia (≥2 hyperkalemia events within 1 year [hyperkalemia event: hyperkalemia diagnosis or potassium [K+]>5 mmol/l]; index was the first hyperkalemia event) with an exact- and propensity score-matched cohort of patients with normokalemia (K+ ≥3.5 to ≤5 mmol/l; random K+ as index) and separately with a matched cohort of patients with nonrecurrent hyperkalemia (1 hyperkalemia event within 1 year; index was hyperkalemia event). Patient characteristics, medication use, HRU, and medical costs were compared between cohorts using standardized mean differences during the 12-month baseline period. All-cause HRU and medical costs during the 12-month follow-up were compared using Wilcoxon rank sum tests for continuous variables and McNemar tests for categorical variables. Substudies of recurrent hyperkalemia vs normokalemia were conducted for patients with Medicare coverage and renin-angiotensin-aldosterone system inhibitor (RAASi) use.

RESULTS

The recurrent hyperkalemia vs normokalemia sample comprised 4,549 matched pairs (Medicare substudy: 3,151; RAASi substudy: 3,535) and the recurrent hyperkalemia vs nonrecurrent hyperkalemia sample comprised 1,599 matched pairs. Baseline characteristics, HRU, and medical costs of the cohorts were similar after matching. During follow-up, patients with recurrent hyperkalemia had a mean of 11.2 more health care encounters (0.5 more inpatient admissions, 0.3 more emergency department visits, and 7.2 more outpatient visits) than patients with normokalemia. Patients with recurrent hyperkalemia also had double the total annual medical costs vs normokalemia ($34,163 vs $15,175; < 0.001), mainly driven by inpatient costs ($21,250 vs $7,392), which accounted for 62.2% and 48.7% of total costs, respectively. Results were similar in the RAASi and Medicare substudies. Recurrent hyperkalemia was associated with a mean 4.3 more all-cause health care encounters and $14,057 higher medical costs (both < 0.001) than nonrecurrent hyperkalemia.

CONCLUSIONS

Recurrent hyperkalemia in patients with stage 3/4 CKD was associated with higher all-cause HRU and medical costs compared with normokalemia (including in patients with Medicare coverage and RAASi use) and nonrecurrent hyperkalemia. Research is needed to understand if long-term treatment strategies aimed at preventing hyperkalemia recurrence may alleviate this economic burden.