Development and validation of a prediction score for postoperative acute renal failure following liver resection

OBJECTIVE:: To develop and validate a score to predict postoperative acute renal failure (ARF) after liver resection. BACKGROUND:: Postoperative ARF after major surgery is associated with morbidity and mortality. Early identification of patients at risk of ARF is important in order to provide protective kidney treatment. METHODS:: Postoperative ARF was prospectively assessed in consecutive patients undergoing liver resection. In randomly selected two-third of the total number of patients, multivariate logistic regression analysis was used to develop a new prediction score (including a full and a reduced model), based on the preoperative parameters of age, gender, preexisting chronic renal dysfunction, cardiovascular disease, diabetes, bilirubin, and alanine aminotransferase (ALT) levels. In the remaining last third of the patients, the new score was validated by calibrating the accuracy of the score (ClinicalTrials.gov NCT 00743132). RESULTS:: Postoperative ARF occurred in 15.1% (86 of 569 consecutive patients) from 2002 to 2007 and was highly associated with mortality (22.5% vs. 0.8% without ARF, P <0.001). In the 380 (two-third of the population) patients selected for the development of the prediction score, preoperatively elevated ALT, preexisting cardiovascular disease, chronic renal failure, and diabetes were the strongest predictors of ARF. Validating the full prediction model (0-22 points) to the remaining 189 patients (one-third of the population), the risk could be predicted accurately (mean predicted risk of 11.5% vs. an observed risk of 14.8%) without significant differences between predicted and observed risks across different risk categories (P = 0.98). Prediction with the reduced model including the 4 strongest predictors (0-7 points) was almost as accurate as with the full model (11.4% predicted vs. 14.8% observed) and also without significant differences across different risk categories (P = 0.75). CONCLUSIONS:: The new prediction score (the full as well as the reduced model) accurately predicted postoperative ARF after liver resection. The use of these scores allows early identification of patients at high risk of ARF, and may support decision making for protective kidney interventions perioperatively.