Effects of Vitamin C Supplements on Clinical Outcomes and Hospitalization Duration for Patients with Coronavirus Disease 2019 (COVID-19): A Systematic Review and Meta-Analysis.

2024-11-11
Nutrition reviews 83(7)
- Maorong Qin
- Kun Xu
- Zhuo Chen
- Xiaojie Wen
- Yifu Tang
- Yangyu Gao
- Hao Zhang
- Xingming Ma

PubMed: 39527016
DOI: 10.1093/nutrit/nuae154

Study Design

Type: Meta-Analysis
Sample size: n = 3,429
Population: 22 studies, with a total of 3429 patients
Methods: Meta-analysis and systematic review; databases searched for publications between January 2020 and December 2023; randomized controlled trial, cohort studies, and retrospective studies in which vitamin C supplementation was supplemented as monotherapy or in combination, compared with placebo, no treatment, or other standard treatment without vitamin C

Context

Vitamin C has been used as an essential antioxidant to reduce the inflammatory response associated with pneumonia and acute respiratory distress syndrome in patients with the 2019 coronavirus disease (COVID-19), but its effect on clinical outcomes remains controversial and inconclusive.

Objective

The purpose of this study was to conduct a meta-analysis and systematic review to assess the effects of vitamin C supplementation on the severity of COVID-19 in hospitalized patients.

Data sources

Web of Science, Embase, Cochrane Library, PubMed, CNKI, CSTJ, Wan fang, and CBM databases were searched for publications between January 2020 and December 2023 that met the inclusion criteria.

Data extraction

The meta-analyses of outcomes in more than one study were performed using Review Manager software. Heterogeneity was evaluated using the I2 statistic. A randomized controlled trial, cohort studies, and retrospective studies in which vitamin C supplementation was supplemented as monotherapy or in combination, compared with placebo, no treatment, or other standard treatment without vitamin C were included.

Data analysis

After screening, 22 studies, with a total of 3429 patients, were selected for assessment. Odds ratios (ORs) with 95% CIs were calculated using fixed- and random-effects models. The meta-analysis showed significant effects of vitamin C on alleviating clinical outcomes in patients with COVID-19 (OR = 0.76, 95% CI = 0.65-0.89, P = .0007) but no shortening of the length of hospitalization (MD = 1.16, 95% CI = -0.13-2.44, P = .08) compared with the control group. Notably, vitamin C supplements significantly reduced the mortality risk (OR = 0.64, 95% CI = 0.51-0.80, P = .0001) and the incidence of severity (OR = 0.59, 95% CI = 0.43-0.80, P = .0006) in COVID-19 patients.

Conclusion

The findings suggest that vitamin C supplements may have a beneficial effect on clinical outcomes, as well as reducing severity and mortality in COVID-19 patients, but more clinical randomized controlled trials are needed to evaluate the role of vitamin C in treating COVID-19.

Systematic review registration

PROSPERO registration no. CRD42023491517.

Research Insights

Vitamin C→Alleviated Clinical Outcomes
The meta-analysis showed significant effects of vitamin C on alleviating clinical outcomes in patients with COVID-19 (OR = 0.76, 95% CI = 0.65-0.89, P = .0007)
Effect
Beneficial
Effect size
Small
Dose
not stated in abstract
Vitamin C→Reduced Disease Severity
the incidence of severity (OR = 0.59, 95% CI = 0.43-0.80, P = .0006) in COVID-19 patients
Effect
Beneficial
Effect size
Moderate
Dose
not stated in abstract
Vitamin C→Reduced Length of Hospitalization
no shortening of the length of hospitalization (MD = 1.16, 95% CI = -0.13-2.44, P = .08) compared with the control group
Effect
Neutral
Effect size
Small
Dose
not stated in abstract
Vitamin C→Reduced Mortality Risk
vitamin C supplements significantly reduced the mortality risk (OR = 0.64, 95% CI = 0.51-0.80, P = .0001)
Effect
Beneficial
Effect size
Moderate
Dose
not stated in abstract