Nishimoto M, Murashima M, Kokubu M, et al. - Researchers intended to determine if there is a connection between preoperative proteinuria and postoperative acute kidney injury (AKI) in noncardiac surgery. The sample consisted of adults who had noncardiac surgery under general anesthesia from 2007 to 2011 at Nara Medical University Hospital. Excluded were those with obstetric or urological surgery, missing data for analyses or preoperative dialysis. Three hundred nine developed AKI among 5,168 individuals. The results obtained from the retrospective cohort study indicated an independent association of preoperative proteinuria with postoperative AKI in noncardiac surgery. According to subgroup analyses, proteinuria was particularly linked to postoperative AKI among patients with renin-angiotensin system inhibitors, other anti-hypertensives, hypoalbuminemia or impaired renal function. Proteinuria patients should be carefully managed to avoid perioperative AKI.