Associations of Dysnatremia with COVID-19 status and Mortality

Abstract

Background: In patients without COVID-19, dysnatremia is associated with mortality. These relationships are not well established in patients with COVID-19. We tested the hypotheses that patients with COVID-19 were more likely to have dysnatremia than those without COVID-19; and that among those with COVID-19, dysnatremia is associated with mortality. Methods: We conducted a retrospective observational study of patients admitted to a tertiary care center in the Bronx, NY during the COVID-19 surge from March 11th to April 26th, 2020. Using multinomial logistic regression models, we compared the prevalence of hypernatremia (serum sodium ≥150 mEq/L) and hyponatremia (serum sodium <130 mEq/L) on admission between patients with COVID-19 and those without. Among patients with COVID-19, we used Cox proportional hazards models to examine the association of dysnatremia with mortality. Results: Compared to those without COVID-19 (n=1,265), patients with COVID-19 (n=3,345) had a higher prevalence of hypernatremia (7.3% vs. 3.6%, p<0.001) and hyponatremia (6.9% vs. 5.5%, p=0.04). In adjusted models, COVID-19 positive patients had a higher likelihood to have hypernatremia, adjusted Odds Ratio=1.87, 95% CI: (1.30, 2.57), p=0.001, compared to COVID-19 negative patients, while the association between hyponatremia and COVID-19 status was no longer significant (p=0.06). Among patients with COVID-19, 775 (23.2%) died after a median follow up of 17 days (IQR: 7-27). Among non-survivors, 14.5% had hypernatremia and 7.6% had hyponatremia on admission. Hypernatremia was associated with a higher risk of mortality (adjusted Hazard Ratio=1.28, 95% CI: (1.01, 1.63), p=0.04) compared to patients with eunatremia. Conclusions: In patients hospitalized during the Spring 2020 COVID-19 surge, COVID-19 status was associated with hypernatremia on admission. Among patients with COVID-19, hypernatremia was associated with higher mortality. Hypernatremia may be a potential prognostic marker for mortality in COVID-19 patients.