Cohort Study to Determine the Association Between Vitamin D Deficiency and Severity of the Disease in Patients With Coronarvirus Disease 2019 (COVID-19)

Coronavirus disease 2019 (COVID-19) can induce an exaggerated inflammatory response. Vitamin D is a key modulator of the immune system. We hypothesized that vitamin D deficiency (VDD) could increase the risk of developing severe COVID-19 infection. The COVIT-D study (Increased risk of severe COVID-19 infection in patients with Vitamin D deficiency) is a prospective cohort study recruiting patients with confirmed COVID-19 seen at the emergency department of a tertiary hospital. A measurement of 25-hydroxyvitamin D is obtained at admission and follow-up obtained. The primary outcome is a composite of death, admission to the intensive care unit, and/or a need for higher oxygen flow than that provided by nasal cannula. The primary association between VDD - categorised in groups - and the primary outcome will be evaluated with univariate analyses and multivariable logistic regression including the following prespecified confounders: age, gender, obesity and chronic kidney disease. The estimated sample size is n=500 and the expected inclusion time lapse 3 months.