Twelve trials, with 1,324 participants, were included in the review. Eight trials were rated high quality, three moderate and one low.
Primary outcomes: There were no statistically significant differences between N-acetylcysteine and control groups for renal failure (odds ratio 0.89, 95% confidence interval (CI): 0.68 to 1.15), renal failure requiring dialysis (odds ratio 1.09, 95% CI: 0.57 to 2.09) or mortality (odds ratio 0.95, 95% CI: 0.53 to 1.71). There was no significant statistical heterogeneity for these outcomes. The effect of N-acetylcysteine on the primary outcomes remained non-significant in all the subgroup and sensitivity analyses.
Secondary outcomes: Treatment with N-acetylcysteine did not reduce length of hospital stay (weighted mean difference 0.34 days, 95% CI: -0.56 to 1.25) but there was significant statistical heterogeneity. Results for other secondary outcomes were reported.