Does ascorbic acid protect against contrast-induced acute kidney injury in patients undergoing coronary angiography: a systematic review with meta-analysis of randomized, controlled trials.

OBJECTIVES This study sought to perform a systematic review with meta-analysis of randomized controlled trials comparing the use of ascorbic acid with placebo or other treatment options for the treatment of contrast induced-acute kidney injury (CI-AKI) in patients undergoing coronary angiography. BACKGROUND CI-AKI remains the most widely discussed and debated topic in cardiovascular medicine, with its incidence increasing due to an increasing number of contrast media-enhanced radiological procedures being performed. METHODS MEDLINE, Embase, and Cochrane central databases were searched from inception to May 2013, without language restrictions. For a study to be selected, it had to report the incidence of CI-AKI as an outcome measure. Studies were excluded if at least 1 study arm did not have ascorbic acid administered alone or with saline solution hydration. Data were extracted by 1 author, and random checks were made by another author. RESULTS Nine randomized, controlled trials reported data on the incidence of CI-AKI in 1,536 patients who had completed the trial and were included in the final analysis. Patients receiving ascorbic acid had 33% less risk of CI-AKI compared with patients receiving placebo or an alternate pharmacological treatment (risk ratio by random-effects model: 0.672; 95% confidence interval, 0.466 to 0.969; p = 0.034). CONCLUSIONS Ascorbic acid provides effective nephroprotection against CI-AKI and may form a part of effective prophylactic pharmacological regimens.