Plain language summary
For centuries, Vitamin C has been known as an important part of human health. Initially, deficiency was associated with scurvy, however subsequent research has found links between administration of Vitamin C and a number of conditions, including lowering blood pressure, decreasing blood glucose levels in Type 2 diabetes and shortening the duration of the common cold. This meta-analysis of 18 controlled trials examined the effect of Vitamin C on the length of ICU stay or the duration of mechanical ventilation. Doses varied from 1-3g daily orally and 0.5-110g daily intravenously and from 1-4 days in duration. The authors found that in 12 of the trials (1766 patients), Vitamin C shortened the length of ICU stay by 8%. 6 trials reported that Vitamin C shortened the length of mechanical ventilation by 8%. Given the significant price difference between Vitamin C supplementation and ICU stay, the authors suggest that further research is justified on the basis of these findings.
Abstract
A number of controlled trials have previously found that in some contexts, vitamin C can have beneficial effects on blood pressure, infections, bronchoconstriction, atrial fibrillation, and acute kidney injury. However, the practical significance of these effects is not clear. The purpose of this meta-analysis was to evaluate whether vitamin C has an effect on the practical outcomes: length of stay in the intensive care unit (ICU) and duration of mechanical ventilation. We identified 18 relevant controlled trials with a total of 2004 patients, 13 of which investigated patients undergoing elective cardiac surgery. We carried out the meta-analysis using the inverse variance, fixed effect options, using the ratio of means scale. In 12 trials with 1766 patients, vitamin C reduced the length of ICU stay on average by 7.8% (95% CI: 4.2% to 11.2%; p = 0.00003). In six trials, orally administered vitamin C in doses of 1⁻3 g/day (weighted mean 2.0 g/day) reduced the length of ICU stay by 8.6% (p = 0.003). In three trials in which patients needed mechanical ventilation for over 24 hours, vitamin C shortened the duration of mechanical ventilation by 18.2% (95% CI 7.7% to 27%; p = 0.001). Given the insignificant cost of vitamin C, even an 8% reduction in ICU stay is worth exploring. The effects of vitamin C on ICU patients should be investigated in more detail.
Methodological quality
Jadad score
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Allocation concealment
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