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Meta-Analysis
. 2021 Apr 29;11(1):9225.
doi: 10.1038/s41598-021-88864-7.

A meta-analysis of randomized clinical trials on the impact of oral vitamin C supplementation on first-year outcomes in orthopedic patients

Kuo-Chuan Hung  1   2 , Min-Hsien Chiang  3 , Shao-Chun Wu  3 , Ying-Jen Chang  1   4 , Chun-Ning Ho  1 , Li-Kai Wang  1   2 , Jen-Yin Chen  1 , Kee-Hsin Chen #  5   6   7   8 , Cheuk-Kwan Sun #  9   10
Affiliations
Meta-Analysis

A meta-analysis of randomized clinical trials on the impact of oral vitamin C supplementation on first-year outcomes in orthopedic patients

Kuo-Chuan Hung et al. Sci Rep. .

Abstract

This meta-analysis aimed at investigating the impact of oral vitamin C supplementation on the post-procedural recovery of orthopedic patients, including functional outcomes and complex regional pain syndrome type I (CRPS I). Literature search using the Medline, Cochrane Library, and Embase databases from inception till March 2021 identified seven eligible randomized controlled trials with 1,361 participants. Forest plot revealed no significant difference in the functional outcomes at 6-12 months [standardized mean difference (SMD) = -0.00, 95% CI - 0.19 to 0.18, 467 patients], risk of overall complications (RR = 0.98, 95% CI 0.68 to 1.39, 426 patients), and pain severity at 3-6 months (SMD = - 0.18, 95% CI - 0.49 to 0.12, 486 patients) between patients with and without oral vitamin C supplementation. Pooled analysis showed that vitamin C treatment reduced the risk of CRPS I regardless of dosage (RR = 0.46, 95% CI 0.25 to 0.85, 1143 patients). In conclusion, the current meta-analysis demonstrated that oral vitamin C supplementation may reduce the risk of complex regional pain syndrome type I but did not improve the functional outcomes in orthopedic patients. Nevertheless, because of the small number of trials included in the present study, further large-scale clinical studies are warranted to support our findings.

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Conflict of interest statement

The authors declare no competing interest.

Figures

Figure 1
Figure 1
PRISMA flowchart for selecting eligible studies. RCT: randomized controlled trial.
Figure 2
Figure 2
Risks of bias of individual studies.
Figure 3
Figure 3
Forest plot for the comparison of function outcomes at 3–6 months between vitamin C and placebo groups. CI, confidence interval; IV, inverse variance; Std., standardized.
Figure 4
Figure 4
Forest plot for the comparison of function outcomes at 6–12 months between vitamin C and placebo groups. CI, confidence interval; IV, inverse variance; Std., standardized.
Figure 5
Figure 5
Forest plot for the comparison of risk of complex regional pain syndrome I between vitamin C and placebo groups at follow-up of 12 months. CI, confidence interval; M–H, Mantel–Haenszel.
Figure 6
Figure 6
Forest plot for the comparison of risk of complex regional pain syndrome I between vitamin C (dosage ≥ 500 mg daily) and placebo groups at follow-up of 12 months. CI, confidence interval; M–H, Mantel–Haenszel.
See this image and copyright information in PMC

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