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.