Vitamins for Prevention of Contrast-induced Acute Kidney Injury: A Systematic Review and Trial Sequential Analysis.

BACKGROUND: To date, universally accepted preventive measures for contrast-induced acute kidney injury (CI-AKI) do not exist, and they warrant further research.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of vitamins, including vitamin C and E, for prevention of CI-AKI.

METHODS: We electronically searched the MEDLINE, EMBASE, and Cochrane databases. The outcome of interest was the incidence of CI-AKI.

RESULTS: A total of 19 studies were included in this meta-analysis. Pooled analysis showed that vitamin C plus saline [relative risk (RR) = 0.63, 95% confidence interval (CI) 0.49-0.82, p = 0.0005] and vitamin E plus saline (RR = 0.39, 95% CI 0.24-0.62, p < 0.0001) significantly reduced the incidence of CI-AKI compared to saline alone. The effect of vitamin C plus saline was further confirmed by trial sequential analysis (TSA). However, TSA indicated that more trials are required to confirm the efficacy of vitamin E plus saline. There was no significant difference in preventing CI-AKI between vitamin C and N-acetylcysteine (NAC) (RR = 0.90, 95% CI 0.47-1.71, p = 0.75), between vitamin C plus NAC and saline (RR = 0.62, 95% CI 0.30-1.30, p =  0.20), as well as between vitamin C plus NAC and NAC (RR = 0.97, 95% CI 0.49-1.92, p = 0.93).

CONCLUSIONS: Vitamin C plus saline administration is effective at reducing the risk of CI-AKI. Evidence for the use of vitamin E plus saline in this context is encouraging, but more trials are required. Furthermore, this meta-analysis and TSA indicated insufficient power to draw a definitive conclusion on the effect of vitamin C plus NAC, versus saline or NAC alone, which needs to be explored further.