Vitamin D supplementation and COVID-19 treatment: A systematic review and meta-analysis.

This systematic review and meta-analysis of 5 studies found no significant difference with vitamin-D supplementation on major health related outcomes in COVID-19.

• The search revealed 5 studies (3 RCTs and 2 Quasi-experimental) including 467 patients across the 5 studies.
• The included studies suffered from significant baseline heterogeneity with respect to drug dosing and population characteristics.
• Bias assessment was completed by 2 authors who rated the certainty of evidence as very low for the outcome’s mortality, ICU admission and mechanical ventilation, which means that any estimate of effect is very uncertain and the author’s indicated they had little confidence in the effect.
• Due to significant heterogeneity random-effects models were used for outcome mortality, mechanical ventilation, and ICU admission.
• Mortality was reported in four studies involving 427 subjects (242 intervention and 185 control/placebo) among which two studies reported mortality benefit and others reported no benefit. In the present review, pooled analysis of the mortality rate in the intervention group (3.43% less mortality) as compared to placebo/controls was observed to be lower, although it was not statistically significant.
• Only two studies reported the mechanical ventilation outcome (MVO) involving 313 subjects (169 intervention and 144 control/placebo). In the present meta-analysis, pooled data did not show a statistically significant improvement in the intervention group, although reduction in 9% requirement for MVO by the intervention group was observed.
• ICU admission was reported by two studies involving 313 subjects (169 intervention and 144 control/placebo). In the present review pooled data failed to show a statistically significant reduction in ICU admission in the intervention group.
• Only one study evaluated all the inflammatory markers like fibrinogen, ferritin, d-dimer, CRP.This study showed significant reduction of fibrinogen values in intervention group vs. control group. The remaining values were insignificant. Because of a lack of data, the authors were unable to include quantitative data for the markers d-dimer and CRP therefore only qualitative data were taken out of two studies (total 277 subjects, n = 135 for intervention and n = 142 for control).
• Results of the review suggest that administration of vitamin D after diagnosis of SARS-CoV-2 infection did not reduce major health outcomes (mortality, ICU admission and need for invasive ventilation).

467 patients diagnosed with COVID-19 from 5 different studies

• In any systematic review and meta-analysis, the exclusion inclusion criteria can limit study selection and thus limit the analyzed data.
• There were very few studies included in this review/meta-analysis.
• In the studies included in this review outcomes like mortality were assessed without taking into account time frame. A longer follow up, taking into account delayed mortality might influence findings.
• The authors reported significant heterogeneity across the studies indicating that the study subjects were very different at baseline making any outcomes hard to compare across studies.
• Dosage of Vitamin-D was very different across studies.
• There were not enough data to conduct a meta-regression which limits the strength of the conclusions.

No significant difference with vitamin-D supplementation on major health related outcomes in COVID-19. Well-designed RCTs are required addressing this topic.

• Systematic review and meta-analysis of randomized, controlled trials and quasi-experimental studies, evaluating the role of vitamin D supplementation in COVID-19 patients.
• The aim was to assess the impact of vitamin D supplementation on clinical outcomes (mortality, ICU admission, mechanical ventilation, and change in inflammatory markers) in patients diagnosed with COVID-19.

Rawat D, Roy A, Maitra S, Shankar V, Khanna P, Baidya DK. “Vitamin D supplementation and COVID-19 treatment: A systematic review and meta-analysis”. Diabetes Metab Syndr. 2021;15(4):102189. doi:10.1016/j.dsx.2021.102189.