Postdischarge Health Care Costs and Readmission in Patients With Hyperkalemia-Related Hospitalizations

Introduction: Limited evidence is available regarding the postdischarge economic and readmission burdens of hyperkalemia. Methods: Using the IBM MarketScan Commercial and Medicare-Supplemental Claims database (January 1, 2010-December 31, 2014), adult patients with a hospitalization with a hyperkalemia diagnosis (ICD-9-CM 276.7, hyperkalemia cohort) were 1:1 matched with patients with a hospitalization without evidence of hyperkalemia (nonhyperkalemia cohort) on age, chronic kidney disease stage, heart failure, dialysis, renin-angiotensin-aldosterone system inhibitor use, and major diagnostic categories of the hospitalization. All cause health care costs and health care resource utilization measures were compared between cohorts during the 1-year postdischarge period. Postdischarge readmission and length of stay (LOS) were compared between hyperkalemia-related hospitalizations from the hyperkalemia cohort and matched hospitalizations unrelated to hyperkalemia from the nonhyperkalemia cohort. Results: Patients with hyperkalemia-related hospitalizations (n = 4426) incurred $30,379 (95% confidence interval, $25,423-$35,335) higher 1-year total all-cause costs ($68,861 vs. $38,482) and had higher rates of inpatient admissions (1.0 vs. 0.4), emergency department visits (2.0 vs. 1.2), and outpatient visits (49.6 vs. 39.1) than the nonhyperkalemia cohort during the 1-year postdischarge study period (all P < 0.001). Hyperkalemia-related hospitalizations (n = 5377) were associated with significantly higher readmission rates (within 30 days: 0.15 vs. 0.09; 60 days: 0.25 vs. 0.16; 90 days: 0.36 vs. 0.23; all P < 0.001), longer LOS per readmission (8.1 vs. 7.1 days), and longer total inpatient days (10.5 vs. 5.8 days) compared with hospitalizations unrelated to hyperkalemia (all P < 0.001). Similar trends were observed across comorbidity subgroups. Conclusion: Hyperkalemia-related hospitalizations were associated with significant economic and readmission burdens during the 1-year postdischarge period.