A recent meta-analysis by Su et al1 compared 12 different prophylactic interventions against contrast medium–induced acute kidney injury (CIAKI). In their meta-analysis, Su et al pooled different vitamins into a single group of “vitamins and analogues,” but in so doing, did not take into account that vitamin C is water soluble whereas vitamin E is fat soluble, and therefore their relative effects might be different. Su et al calculated an odds ratio of 0.64 (with a 95% credible interval of 0.41-0.95) for the effect of “vitamins and analogues,” but they did not calculate the specific individual effects of vitamins E and C.