Hospital and Laboratory Outcomes of Patients with COVID-19 who Received Vitamin D Supplementation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This meta-analysis found that vitamin D supplementation reduced the risk of ICU admission in patients with COVID-19 but not for other COVID-19 outcomes.

• 9 RCTs including 1586 confirmed COVID-19 patients with a mean age of 56.41±11.69 were included in the analysis.   
• The intervention and control groups ranged from 16 to 274 participants. Most patients received oral vitamin D administration, but in one study patients received vitamin D via intramuscular injection. 
• Patients receiving vitamin D showed a significant reduction in ICU admission, as well as a greater change in vitamin D levels when compared to control groups.  
• There was no significant difference between vitamin D and control groups for all other hospital and laboratory outcomes studied.  

Nine clinical studies including 1596 adult patients with confirmed COVID-19 infection were included in the analyses. 

• High heterogeneity was observed between studies, such as different populations’ characteristics including age, sex, race, the severity of COVID-19 symptoms, treatment protocol, and associated comorbidities. 
• Vitamin D treatment varied in dose, form, timing of administration, and patient’s baseline levels of vitamin D. Patients received variable amounts of vitamin D, ranging from low to high doses (up to 500,000 IU), and from single dose to daily doses administered for up to 2 months.  
• Not all studies included each of the outcomes evaluated. 

Our study suggested that vitamin D supplementation benefits COVID‐19 patients by reducing ICU admission and increasing changes in vitamin D levels. However, it produces no difference in other outcomes compared to no vitamin D intake. The definite role of vitamin D on COVID‐19 outcomes strongly needs further well-conducted and high-quality research, especially after its known effect on the body’s immune system and defense mechanisms and the previously collected data on its benefits on certain respiratory diseases, including COVID-19.

• This systematic review and meta-analysis evaluated the effect of vitamin D supplementation on hospital and laboratory outcomes in patients with COVID-19.  
• Five databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) and clinicaltrials.gov were searched until July 2022.  
• Eligible randomized clinical trials (RCTs) included COVID-19 patients who received vitamin D supplementation (any type) and compared hospital and laboratory outcomes with similar patients who received no intervention or placebo.  
• Hospital outcomes included the need for intensive care unit (ICU) admission, ventilation and oxygen therapy, risk of death, and length of hospital stay. Laboratory outcomes included levels of vitamin D, C-reactive protein, interleukin-6, lactate dehydrogenase, calcium concentration, creatinine, d-dimer, neutrophil count, lymphocyte count, platelet count, and leucocytes.

Zaazouee MS, Eleisawy M, Abdalalaziz AM, Elhady MM, Ali OA, Abdelbari TM, Hasan SM, Almadhoon HW, Ahmed AY, Fassad AS, Elgendy R, Abdel-Baset EA, Elsayed HA, Elsnhory AB, Abdraboh AB, Faragalla HM, Elshanbary AA, Kensara OA, Abdel-Daim MM. Hospital and laboratory outcomes of patients with COVID-19 who received vitamin D supplementation: a systematic review and meta-analysis of randomized controlled trials. Naunyn Schmiedebergs Arch Pharmacol. 2023 Apr;396(4):607-620. doi: 10.1007/s00210-022-02360-x. Epub 2022 Dec 12.