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Review
. 2022 Dec 5;10(12):2456.
doi: 10.3390/healthcare10122456.

Association of Vitamin C Treatment with Clinical Outcomes for COVID-19 Patients: A Systematic Review and Meta-Analysis

Wen Yan Huang  1   2   3 , Jiyoun Hong  1   3 , Sung-Il Ahn  3 , Bok Kyung Han  1   3 , Young Jun Kim  1   2   3
Affiliations
Review

Association of Vitamin C Treatment with Clinical Outcomes for COVID-19 Patients: A Systematic Review and Meta-Analysis

Wen Yan Huang et al. Healthcare (Basel). .

Abstract

Background: Vitamin C is an essential nutrient that serves as an antioxidant and is known to reduce the inflammatory response associated with pneumonia and acute respiratory distress syndrome in patients with the coronavirus disease (COVID-19), but its clinical effects remain controversial. Methods: This study aimed to investigate the therapeutic effect of vitamin C administration on the clinical outcomes of COVID-19 patients through a systematic review and meta-analysis. Results: Nineteen studies were selected, of which 949 participants administered vitamin C were in the intervention group, and 1816 participants were in the control group. All-cause mortality, hospitalization duration, length of intensive care unit stay, and ventilation incidence in COVID-19 patients were analyzed. The intervention group tends to have a lower risk ratio (RR = 0.81, 95% CI: 0.62 to 1.07; I2 = 58%; Q = 40.95; p < 0.01) in all-cause mortality than the control group. However, there were no significant differences in ventilation incidence, hospitalization duration, and length of ICU stay between the two groups. In the subgroup analysis for all-cause mortality, the risk ratio for RCT as study design, combination therapy, of vitamin C was lower than that of the combination therapy with other agents. A moderate dosage showed a lower RR than a higher dose. Conclusion: The results suggest that vitamin C may lower mortality in COVID-19 patients, but further large-scale studies are required to assess the role of vitamin C in the treatment of COVID-19.

Keywords: COVID-19; hospitalization; meta-analysis; mortality; systematic review; vitamin C.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The PRISMA 2020 flow diagram for the meta-analysis.
Figure 2
Figure 2
Traffic light plot of risk of bias assessment of included studies using RoB 2.0 criteria, and overall risk of bias.
Figure 3
Figure 3
Results of the meta-analysis on the difference in the risk ratio (RR) for (a) all-cause mortality, (b) ventilation incidence, (c) mean difference for hospitalization duration, and (d) length of ICU stay between intervention and control groups.
Figure 3
Figure 3
Results of the meta-analysis on the difference in the risk ratio (RR) for (a) all-cause mortality, (b) ventilation incidence, (c) mean difference for hospitalization duration, and (d) length of ICU stay between intervention and control groups.
Figure 4
Figure 4
Subgroup analysis for all-cause mortality according to (a) study design (non-RCT vs. RCT), (b) treatment method (monotherapy vs. combination therapy), (c) route (IV vs. oral), and (d) dosage (moderate vs. high).
Figure 4
Figure 4
Subgroup analysis for all-cause mortality according to (a) study design (non-RCT vs. RCT), (b) treatment method (monotherapy vs. combination therapy), (c) route (IV vs. oral), and (d) dosage (moderate vs. high).
Figure 5
Figure 5
Funnel plots for publication bias evaluation. (a) All-cause mortality, (b) ventilation incidence, (c) hospitalization duration, and (d) length of ICU stay between intervention and control groups.
See this image and copyright information in PMC

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