Fig. 2

Forest plot for postoperative acute kidney injury (AKI) (defined as the proportion of patients who developed postoperative worsening of renal function, whichever definition was used by the authors of the included studies). Studies were split in high and low risk of bias, according to a domain-based evaluation, as proposed by the Cochrane Collaboration. RCTs with 5 or 6 green plus were considered as having an overall low risk of bias (see text for details). Size of squares for odds ratio reflects weight of trial in pooled analyses. Horizontal bars represent 95% confidence intervals