ABSTRACT
Background: COVID-19 is a major worldwide health problem because of acute respiratory distress syndrome, and mortality. Several lines of evidence have suggested a relationship between the vitamin D endocrine system and severity of COVID-19. Methods: We present a retrospective survival study that includes all Andalusian patients hospitalized between January and November 2020 because of COVID-19 infection. Based on a central registry of electronic health records (the Andalusian Population Health Database, BPS), prescription of vitamin D or its metabolites within 15-30 days before hospitalization were recorded. The effect of treatment with vitamin D metabolites for other indication previous to the hospitalization was studied with respect to patient survival by means of Kaplan-Meyer survival curves and Log Hazard Ratios, using a propensity score to compensate the disbalance of compared classes and the confounding factors. The availability of detailed patient data in the BPS allowed to obtain Real-World Evidence (RWE) of the effects of prior use of vitamin D or its metabolites on the mortality due to COVID-19 infection. Findings: A retrospective cohort of 16.401patients was extracted from the BPS, which includes all the patients hospitalized with COVID-19 diagnosis between January and November 2020 in Andalusia, one of the largest regions in Europe with the size of an average median country. A total of 358 patients were found with cholecalciferol, and 193 with calcifediol, prescriptions 15 days before hospitalization. For a period extended to 30 days before hospitalization, the numbers increase to 416 and 210 and, respectively. Kaplan-Meyer survival curves and hazard ratios support an association between consumption of these metabolites and patient survival. Such association was stronger in calcifediol (Log Hazard Ratio, LHR = -1.27{+/-}0.32) than in cholecalciferol (LHR= -0.56{+/-}0.15), when prescribed 15 days before hospitalization This effect decreases when a larger 30 days period is considered (calcifediol LHR= -1.01{+/-}0.27 and cholecalciferol LHR= -0.27{+/-}0.12), suggesting that the closer was the treatment to the hospitalization the stronger the association. Conclusions: A significant reduction in mortality in patients hospitalized with COVID-19 is associated with the prescription of vitamin D, especially calcifediol, within 15-30 days prior to hospitalization.