Analysis of risk factors and development of a prediction model for acute kidney injury in elderly patients after abdominal surgery

OBJECTIVE: To investigate risk factors for postoperative acute kidney injury (AKI) in elderly patients undergoing abdominal surgery, and to develop and validate a prediction model. METHODS: A retrospective analysis of 954 elderly abdominal surgery patients was conducted. AKI was defined as serum creatinine increase ≥26.5 μmol/L within 48 h or ≥1.5× baseline within 7 days post-surgery. Independent risk factors were identified by multivariate logistic regression, and a nomogram was constructed. Model performance was assessed using ROC curve (AUC), calibration curve, DCA, and learning curve. RESULTS: The incidence of postoperative AKI was 11.43%. Independent risk factors included age, aCCI≥4, diabetes, hypertension, anemia, hypoproteinemia, low serum albumin and hemoglobin, and pneumoperitoneum duration. The AUCs for the training, validation, and test sets were 0.872, 0.871, and 0.927, respectively. The calibration curve showed good fit, DCA indicated net clinical benefit, and the learning curve confirmed adequate sample size. CONCLUSION: The nomogram prediction model for postoperative AKI in elderly abdominal surgery patients exhibits good discrimination, accuracy, and clinical utility, supporting early identification of high-risk individuals and perioperative renal protection.