Hyponatremia is Associated with Poor Outcome in COVID-19

Abstract

<title>Abstract</title> Background Hyponatremia has been described in severe acute respiratory syndrome. Our objective was to describe the impact of hyponatremia on COVID-19 patients’ outcome (intensive care unit [ICU] admission, mechanic ventilation or death). Methods According to natremia at admission, two groups were retrospectively screened: hyponatremic (&lt; 135 mM, n = 101) or normonatremic (natremia ≥ 135 mM, n = 222) patients. Pearson’s chi-2 (qualitative variables) and Student tests (quantitative variables) were used to compare the two groups. A multiple logistic regression model was used to assess the association of outcome and patients’ data. Results Hyponatremia was generally mild. There were more male patients in the hyponatremic group (p = 0.005). Pulmonary lesions on the first thoracic CT-scanner performed during the hospitalization were significantly more extended in the hyponatremic group (p = 0.03). ICU admission, mechanic ventilation or death were significantly higher in hyponatremic compared to normonatremic patients (34 versus 14%; p &lt; 0.001; 16% versus 5%; p = 0.002; 19 versus 9%, p = 0.021, respectively). Hyponatremia was an independent predictor of poor outcome (adjusted Odds-ratio: 2.49 [1.18–5.33, p = 0.017]). Conclusions Our study showed an independent relationship between hyponatremia at admission and transfer to ICU, use of mechanic ventilation or death in COVID-19. Hyponatremia may reflect the potential severity of underlying pulmonary lesions. Our results support the use of natremia as a simple bedside screening tool for early identification of SARS-CoV-2 infected patients at high risk of poor outcome.