By a retrospective analysis in COVID-19 patients during the first pandemic period, our group reported a 22.9% prevalence of hyponatremia at hospital admission, with worse respiratory performances (evaluated as P/F, i.e., the ratio between the partial pressure of oxygen in arterial blood PaO2 and the inspired oxygen fraction FiO2) and higher IL-6 levels in hyponatremic vs. normonatremic hospitalized patients [52]. Here, IL6 is linked to Hyponatremia.