Hypophosphatemia at Admission is Associated with Increased Mortality in COVID-19 Patients

Background: Electrolyte disturbances are commonly observed in patients with coronavirus disease 2019 (COVID-19) and associated with outcome in these patients. Our study was designed to examine whether hypophosphatemia is associated with mortality in COVID-19 patients. Methods: Patients diagnosed with COVID-19 and hospitalized in Renmin Hospital of Wuhan University between January 30 and February 24, 2020 were included in this study. Patients were divided into two groups, a hypophosphatemia group and a non-hypophosphatemia group, based on a serum phosphate level of 0.8 mmol/L. Logistic regression was performed to analyze the relationship between hypophosphatemia and mortality. A locally weighted scatterplot smoothing (LOWESS) curve was plotted to show the detailed association between mortality rate and serum phosphate level. A Kaplan-Meier survival curve was drawn to compare the difference in cumulative survival between the two groups. Results: Hypophosphatemia at admission occurred in 33 patients, with an incidence of 7.6%. The hypophosphatemia group had a significantly higher incidence of respiratory failure (54.5% vs 32.6%, p=0.013) and mortality (57.6% vs 15.2%, p<0.001). Multivariate logistic regression indicated that age (OR=1.059, p<0.001), oxygen saturation (OR=0.733, p<0.001), white blood cells (OR=1.428, p<0.001), lymphocytes (OR=0.075, p<0.001) and hypophosphatemia (OR=3.636, p=0.015) were independently associated with mortality in the included patients. The hypophosphatemia group had significantly shorter survival than the non-hypophosphatemia group (p<0.001). Conclusion: Hypophosphatemia at admission is associated with increased mortality in COVID-19 patients. More attention and medical care should be given to COVID-19 patients with hypophosphatemia at admission.