Background: Vitamin C is a well-documented antioxidant that reduces oxidative stress and fluid infusion in high doses; however, the association between high-dose vitamin C and reduced mortality remains unclear. This study evaluates the effect of high-dose vitamin C in severe burn patients under two varying thresholds.
Methods: We enrolled adult patients with severe burns (burn index ≥ 15) who were registered in the Japanese Diagnosis Procedure Combination national inpatient database from 2010 to 2016. Propensity score matching was performed between patients who received high-dose vitamin C within 1 day of admission (vitamin C group) and those who did not (control group). High-dose vitamin C was defined as a dosage in excess of 10 g or 24 g within 2 days of admission. The primary outcome was in-hospital mortality.
Results: Eligible patients (n = 2713) were categorized into the vitamin C group (n = 157) or control group (n = 2556). After 1:4 propensity score matching, we compared 157 and 628 patients who were administered high-dose vitamin C (> 10-g threshold) and controls, respectively. Under this particular threshold, high-dose vitamin C therapy was associated with reduced in-hospital mortality (risk ratio, 0.79; 95% confidence interval, 0.66-0.95; p = 0.006). In contrast, in-hospital mortality did not differ between the control and high-dose vitamin C group under the > 24-g threshold (risk ratio, 0.83; 95% confidence interval, 0.68-1.02; p = 0.068).
Conclusions: High-dose vitamin C therapy was associated with reduced mortality in patients with severe burns when used under a minimum threshold of 10 g within the first 2 days of admission. While "high-dose" vitamin C therapy lacks a universal definition, the present study reveals that different "high-dose" regimens may yield improved outcomes.
Keywords: Ascorbic acid; Burn; Competing risk; Matching; Propensity score; Vitamin C.