In-hospital mortality, length of stay, and hospitalization cost of COVID-19 patients with and without hyperkalemia

BACKGROUND: Hyperkalemia (HK) may be associated with poor clinical outcomes among COVID-19 patients. This study aimed to describe the prevalence of HK and evaluate the associations between HK and in-hospital mortality, intensive care unit (ICU) admission, length of hospital stay (LOS), and hospitalization cost among COVID-19 inpatients. METHODS: A retrospective cohort study was conducted using a large hospital discharge database (PINC AI Healthcare Database) for COVID-19 inpatients discharged between April 1 and August 31, 2020. HK was defined with discharge diagnosis and potassium binder use. RESULTS: Of 192,182 COVID-19 inpatients, 12% (n = 22,702) had HK. HK patients were more likely to be older (median age 67 vs 63 years), male (63% vs 50%), black (30% vs 22%), and have a history of chronic kidney disease (45% vs 16%) or diabetes mellitus (55% vs 35%) than non-HK patients (all p<.001). A significantly higher proportion of patients with HK had in-hospital mortality (42% vs 11%, p<.001) than those without HK; this was persistent after adjusting for confounders (adjusted odds ratio [(a)OR] 1.69, 95% confidence interval [CI]1.62-1.77). Patients with HK were also more likely to be admitted to ICU ((a)OR 1.05, 95% CI 1.01-1.09), incur higher cost of care (adjusted mean difference $5,389) and have longer LOS (adjusted mean difference 1.3 days) than non-HK patients. CONCLUSIONS: Presence of HK was independently associated with higher in-hospital mortality, LOS, and cost of care among COVID-19 inpatients. Detecting and closely monitoring HK are recommended to improve clinical outcomes and reduce LOS and healthcare cost among COVID-19 patients.