Sodium alterations impair the prognosis of hospitalized patients with COVID-19 pneumonia.

OBJECTIVE Dysnatremia is common in hospitalized patients, often worsening the prognosis in pneumopathies and critical illnesses. Information on COVID-19-related hyponatremia is partially conflicting, whereas data on hypernatremia in this context are scarce. We assessed, in a cohort of COVID-19 inpatients: the prevalence of sodium alterations at admission and throughout their hospitalization; their association with inflammation/organ damage indexes; their short-term prognostic impact. STUDY DESIGN AND METHODS 117 patients (81 males, 64±13 years) hospitalized for COVID-19 between 1st March and 30th April 2020 were retrospectively followed-up for their first 21 days of stay by collecting all serum sodium measurements, basal CRP and serum lactate levels, maximum IL-6 and information on care setting, required ventilation, length of hospitalization, in-hospital death. RESULTS At admission, 26.5% patients had hyponatremia, 6.8% had hypernatremia. During their hospitalization, 13.7% patients experienced both disorders ("mixed dysnatremia"). Lower sodium levels at admission were correlated with higher CRP (p=0.039) and serum lactate levels (p= 0.019), but not IL-6. Hypernatremia and a wider sodium variability were associated to maximum required ventilation, need of ICU assistance and duration of the hospitalization. Mean estimated time to ICU admission was 20 days shorter in patients exposed to sodium alterations at any time of their hospital course (Log-Rank test p=0.032). CONCLUSIONS Sodium alterations frequently affect hospitalized COVID-19 patients. Hyponatremia could indicate pulmonary involvement, whereas hypernatremia is associated to prolonged hospitalization and need for intensive care/mechanical ventilation, particularly when resulting from prior hyponatremia. Optimizing in-hospital sodium balance is crucial to improve patients' prognosis.