Vitamin D Treatment Is Associated with Reduced Risk of Mortality in Patients with COVID-19: A Cross-Sectional Multi-Centre Observational Study

Background: The 2019 novel coronavirus disease (Covid-19) worldwide pandemic has posed the most substantial and severe public health issue for several generations, and therapeutic options for it have not yet been optimised. Vitamin D has been proposed in the pharmacological management of Covid-19 by various sources. This study aimed to determine whether Covid-19 disease outcomes were affected by vitamin D status, and to elucidate any predictors of Covid-19 outcomes. Methods: Patients hospitalised with Covid-19 were opportunistically recruited from three different UK hospitals and their data were collected. Logistic regression was used to determine any relationships between vitamin D status and various predictors, including mortality and ventilation, and to determine any relationships between mortality, ventilation, and various predictors. Findings: Vitamin D status was not associated with any outcomes of Covid-19 investigated, following adjustment for age and sex. However, treatment with vitamin D was significantly associated with a reduced risk of death, following adjustment for age and sex (ORadj 0·48, 95% CI 0·32 – 0·70, p = 1·79x10-4). This relationship remained significant when also adjusted for baseline vitamin D levels (ORadj 0·47, 95% CI 0·33 – 0·70, p = 1·27x10-4). Interpretation: Treatment with vitamin D, regardless of baseline serum vitamin D levels, appears to be associated with a reduced risk of mortality in acute in-patients admitted with Covid-19. Further work on large population studies needs to be carried out to determine adequate serum levels of vitamin D, as well as multi-dose clinical trials of vitamin D treatment to assess maximum efficacy. Trial Registration: The study was also registered on Clinicaltrials.gov (reference number NCT04386044), prior to commencement. Funding: None. Declaration of Interests: The authors have no conflicts of interest. Ethics Approval Statement: Ethical approval was granted by the Health and Care Research Wales Research Ethics Committee (IRAS number 285337).