Effect of Vitamin D Supplementation on COVID-19 Patients: A Systematic Review and Meta-Analysis

This meta-analysis found that vitamin D supplementation significantly reduced mortality from COVID-19 in the cohort studies examined, but not in the randomized controlled trials. Supplementation did not reduce ICU admission or rate of ventilation or intubation in COVID-19 patients, but the authors cautioned that further high-quality, larger studies are needed. 

• 16 studies were included in the analysis: 8 RCTS that included 1,318 subjects and 8 cohort studies that included 2,041 subjects. 
• The pooled analysis of RCTs showed that vitamin D supplementation did not have a significant effect on reducing mortality, while the results of cohort studies indicated that vitamin D supplementation did have a positive impact on reducing mortality in COVID-19 patients.  
• There was no statistically significant difference in the rates of ICU admission or rates of mechanical ventilation or intubation. 

16 studies (8 randomized controlled trials and 8 cohort studies) including 3,359 patients hospitalized with COVID-19. 

• There was considerable variation across the different studies, including population characteristics, COVID-19 severity and treatment strategies, and the dose, duration, and type of supplement used. 
• The authors noted that these conclusions should be interpreted with caution due to the small sample size and low quality of some of the included studies.  

While the results of this meta-analysis suggest that vitamin D supplementation may not significantly reduce mortality, ICU admission, and rates of mechanical ventilation intubation in COVID-19 patients, additional well-designed RCTs with large sample sizes are needed to further explore the potential benefit of vitamin D supplementation in this population.

• This systematic review and meta-analysis examined the effect of vitamin D supplementation on mortality, ICU admission, and rates of ventilation or intubation in patients hospitalized with COVID-19.  
• PubMed, Embase, Cochrane Library, CBM, CNKI, VIP, and WanFang databases were searched from December 1, 2019, to December 31, 2022, for randomized controlled trials (RCTs) or cohort studies in COVID-19 patients of all ages and severity levels that compared the effect of vitamin D versus no treatment in COVID-19 outcomes.

Zhang Y, Li J, Yang M, Wang Q. Effect of vitamin D supplementation on COVID-19 patients: A systematic review and meta-analysis. Front Nutr. 2023 Mar 7;10:1131103. doi: 10.3389/fnut.2023.1131103.