The effect of vitamin C on the risk of mortality in patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS: Vitamin C appears to be a viable treatment option for patients with COVID-19. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) of vitamin C versus comparative interventions in patients with COVID-19. The outcome of interest was all-cause mortality. RESULTS: The meta-analysis of eleven trials using a random-effects model revealed significant reduction in the risk of all-cause mortality with the administration of vitamin C among patients with COVID-19 relative to no vitamin C (pooled odds ratio = 0.53; 95% confidence interval 0.30–0.92). Subgroup analysis of studies that included patients with severe COVID-19 also produced findings of significant mortality reduction with the administration of vitamin C relative to no vitamin C (pooled odds ratio = 0.47; 95% confidence interval 0.26–0.84). CONCLUSION: Overall, evidence from RCTs suggests a survival benefit for vitamin C in patients with severe COVID-19. However, we should await data from large-scale randomized trials to affirm its mortality benefits.