In this prospective observational study we aim to study the association of vitamin D deficiency with adverse clinical outcomes in patients infected with Coronavirus disease 2019

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.

Inclusion Criteria:

• >18 years old
• symptoms suggestive of COVID-19
• positive reverse-transcriptase polymerase chain reaction or antibodies for SARS-CoV-2

Exclusion Criteria:

• Bacterial community acquired pneumonia

Consecutive adult subjects attending the emergency department with symptoms suggestive of COVID-19 and a positive reverse-transcriptase polymerase chain reaction for SARS-CoV-2