1. Introduction
illness, COVID-19 disease, viral infections, deaths, coronavirus disease 2019
CORONAVIRUS DISEASE 2019, RESPIRATORY TRACT INFECTIONS, DISEASE, VIRAL INFECTION, SECONDARY, CORONAVIRUS
COVID-19 symptoms vary from asymptomatic cases to moderate and severe illness with patients needing hospitalization and intensive care treatment. Vitamin D is associated with severity of viral infections and has an immune-modulatory effect in immune response. Observational studies showed a negative association of low vitamin D levels and COVID-19 severity and mortality outcomes. In this study, we aimed to determine whether daily supplementation of vitamin D during intensive care unit (ICU) stay in COVID-19 patients with severe illness affects clinically relevant outcomes. Patients with COVID-19 disease in need of respiratory support admitted to the ICU were eligible for inclusion. Patients with low vitamin D levels were randomized into one of two groups: the intervention group received daily supplementation of vitamin D and the control group did not receive vitamin D supplementation. In total, 155 patients were randomized: 78 into the intervention group and 77 into the control group. There was no statistically significant difference in number of days spent on respiratory support, although the trial was underpowered for the main outcome. There was no difference in any of the secondary outcomes analyzed between two groups. Our study suggests no benefit in vitamin D supplementation to patients with severe COVID-19 disease admitted to the ICU and in need of respiratory support in any of the analyzed outcomes.Since December 2019, millions of people have been infected with novel coronavirus (SARS-CoV-2). According to the World Health Organization (WHO), there is more than 250 million confirmed cases of coronavirus disease 2019 (COVID-19) with more than 5 million confirmed deaths across the world [The COVID-19 symptoms vary from asymptomatic cases and mild forms of disease which do not require special medical care to moderate and severe illness with patients needing hospitalization [There is evidence that vitamin D supplementation protects against respiratory tract infections [To improve vitamin D status, high dose supplementation is required [In this study, we aimed to determine whether daily supplementation of vitamin D during intensive care unit (ICU) stay in COVID-19 patients with severe illness affects clinically relevant outcomes.