Negative prognostic impact of electrolyte disorders in patients hospitalized for Covid-19 in a large multicenter study

Background The prognostic impact of electrolyte disorders in hospitalized COVID-19 patients is unclear. Methods The study included all adult patients hospitalized for COVID-19 in four hospitals in Northern Italy between January 2020 and May 2021 with at least one serum potassium and sodium measurement performed within 3 days since admission. Primary outcome was in-hospital death; secondary outcome was Intensive Care Unit (ICU) admission. A cause-specific Cox proportional-hazards regression model was used for investigating the association between potassium and sodium (as either categorical or continuous variables) and mortality or admission to ICU. Results Analyses included 3,418 adult hospitalized COVID-19 patients. At multivariable analysis, both hyperkalemia (Hazard Ratio, [HR] 1.833, 95% Confidence Interval [CI] 1.371-2.450) and sK above the median (K 5.1 vs 4.1 mmol/L: HR 1.523, 95% CI 1.295-1.798), and hypernatremia (HR 2.313, 95%CI 1.772-3.018) and sNa above the median (Na 149 vs 139 mmol/L: HR 1.442, 95% CI 1.234-1.686), were associated with in-hospital death, whereas hypokalemia and hyponatremia were not. Hyponatremia was associated with increased hazard of ICU admission (HR 1.884, 95%CI 1.389-2.556). Conclusions Electrolyte disorders detected at hospital admission may allow early identification of COVID-19 patients at increased risk of adverse outcomes.