Risk factors for postoperative acute kidney injury in a cohort of 2378 patients from 59 hospitals

To assess risk factors for postoperative acute kidney injury (AKI) in adults with normal renal function hospitalized for major surgery. To analyze mortality and length of hospital stay in patients who develop postoperative AKI. Data for analysis were drawn from the 2006 ARISCAT study. The dependent variable was postoperative AKI defined as a decline in renal function demonstrated by a rise in plasma creatinine level to twice the baseline measurement or a 50% reduction in the glomerular filtration rate. Bivariate and multivariate analyses were used to identify preoperative and intraoperative risk factors. We analyzed 2378 of the ARISCAT cases, which had been enrolled from 59 participating hospitals; 25 patients (1.1%) developed AKI. Analysis identified 5 risk factors: age, peripheral arterial disease, type of surgical incision, blood loss, and infusion of colloids. The area under the receiver operating characteristic curve was 0.88% (95% confidence interval, 0.79%-0.69%). Duration of hospital stay was longer for patients with postoperative AKI (21.8 days, vs 5.5 days for other patients; P=.007). Mortality was higher in patients with AKI at 30 days (36% vs 0.9%) and at 3 months (48% vs 1.7%). The incidence of postoperative AKI was slightly over 1%. Knowledge of postoperative AKI risk factors can facilitate the planning of surgical interventions and anesthesia to reduce subsequent morbidity and mortality and length of hospital stay.