Treatment with 25-hydroxyvitamin D3 (calcifediol) is associated with a reduction in the blood neutrophil-to-lymphocyte ratio marker of disease severity in patients hospitalized with COVID-19: a pilot, multicenter, randomized, placebo-controlled double blind clinical trial

Objective The goal of this randomized placebo-controlled clinical trial was to investigate the therapeutic efficacy of oral 25-hydroxyvitamin D3 [25(OH)D3] in improving vitamin D status in vitamin D deficient/insufficient patients infected with the SARS-CoV-2 (COVID-19) virus. Methods This is a multicenter randomized double blinded randomized placebo-controlled clinical trial. Participants were recruited from three hospitals that are affiliated to [Institution Blinded for Review], and [Institution Blinded for Review]. Results A total 106 hospitalized patients who had a circulating concentration of 25(OH)D Conclusion Our analysis indicated that oral 25-hydroxyvitamin D3 was able to correct vitamin D deficiency/insufficiency in COVID-19 patients that resulted in improved immune function by increasing blood lymphocyte percentage. RCTs with a larger sample size and with higher dose of 25(OH)D3 maybe needed to confirm the potential effect of 25(OH)D3 on reducing clinical outcomes in COVID-19 patients. Ethics and dissemination The study protocol was approved by the Ethics Committee of [Institution Blinded for Review]. (Approval Number: IR.TUMS.VCR.REC.1399.061). Dissemination plans include academic publications, conference presentations and social media. Trial registration The protocol was registered with the Iranian Registry of Clinical Trials (IRCT) on April 11, 2020 [Number Blinded for Review]. and U.S. National Institutes of Health [Number Blinded for Review] on May 11, 2020.