The Role of Serum Vitamin D Concentrations in Predicting COVID-19 Course and Outcome

Introduction/Aim. The coronavirus disease 2019 (COVID-19) pandemic had significant acute and longterm impact on people's health. As the available literature sources have shown that the premorbid conditions affect the course of COVID-19, we aimed to investigate the role of admission vitamin D concentration to predict the outcome of hospitalized COVID-19 patients. Methods. An observational, prospective cohort study was conducted on 329 COVID-19 patients hospitalized at the University Clinical Centre Kragujevac, between October and December 2021. Within 24 hours of admission, vitamin D level was measured from the peripheral venous blood. Medical history data and socio-demographic characteristics were obtained anamnestically and using Health Information System (COMTRADE, Serbia). Lethal outcome and intensive care unit (ICU) admission were considered primary end -points. Results. The prevalence of hypovitaminosis D on admission in our cohort was 27.7%. Both non -survivors and patients requiring ICU admission more frequently had hypovitaminosis D compared to survivors (42,9% versus 21,0%; p < 0,001) and patients on a standard level of care (31,5% verus 25,3%; p = 0,029). Our research showed that vitamin D concentration < 20 ng/mL was an independent predictor of mortality (aOR 2.142 [95% CI 1.226 - 3.744]). However, hypovitaminosis D upon hospital admission did not show a significant impact on ICU admission. Conclusion. Low vitamin D concentration on admission could be a significant predictor of outcome in hospitalized COVID-19 patients.