Objective: The pandemic of coronavirus disease (COVID-19) has rapidly spread globally and infected millions of people. The prevalence and prognostic impact of dysnatremia in COVID-19 is inconclusive. Therefore, we investigated the prevalence and outcome of dysnatremia in COVID-19.
Design: The prospective, observational, cohort study included consecutive patients with clinical suspicion of COVID-19 triaged to a Swiss Emergency Department between March and July 2020.
Methods: Collected data included clinical, laboratory and disease severity scoring parameters on admission. COVID-19 cases were identified based on a positive nasopharyngeal swab test for SARS-CoV-2, patients with a negative swab test served as controls. The primary analysis was to assess the prognostic impact of dysnatremia on 30-day mortality using a cox proportional hazard model.
Results: 172 (17%) cases with COVID-19 and 849 (83%) controls were included. Patients with COVID-19 showed a higher prevalence of hyponatremia compared to controls (28.1% vs. 17.5%, p<0.001); while comparable for hypernatremia (2.9% vs 2.1%, p=0.34). In COVID-19 but not in controls, hyponatremia was associated with a higher 30-day mortality (HR 1.4, 95%-CI 1.10-16.62, p=0.05). In both groups, hypernatremia on admission was associated with higher 30-day mortality (COVID-19: HR 11.5, 95%-CI 5.00-26.43, p<0.001; controls: HR 5.3, 95%-CI 1.60-17.64, p=0.006). In both groups, hyponatremia and hypernatremia were significantly associated with adverse outcome, e.g. intensive care unit admission, longer hospitalization, and mechanical ventilation.
Conclusion: Our results underline the importance of dysnatremia as predictive marker in COVID-19. Treating physicians should be aware and appropriate treatment measures taken in patients with COVID-19 and dysnatremia.