Incidence and predictors of postoperative acute kidney injury in older adults with hip fractures

Purpose: To clarify the incidence and predictors of acute kidney injury (AKI) after hip fracture surgery; Secondary Purpose: To investigate the impact of AKI on the length of stay (LOS) and mortality of patients. METHODS: We retrospectively evaluated data from 644 hip fracture patients at Peking University First Hospital from 2015 to 2021, and divided the patients into AKI and Non-AKI groups according to whether AKI occurred after surgery. Logistic regression was used to clarify the risk factors for AKI, draw ROC curves, and analyze the odds ratio (OR) for LOS and death at 30 days, 3 months, and 1 year for patients with AKI. RESULTS: The prevalence of AKI after hip fracture was 12.1%. Age, BMI, and postoperative brain natriuretic peptide (BNP) levels were risk factors for AKI after hip fracture surgery. The risk of AKI in underweight patients, overweight patients and obese patients was 2.24, 1.89, and 2.58 times. Compared to patients with BNP levels <800 pg/ml, the risk of AKI was 22.34-fold for postoperative BNP levels>1500 pg/ml. The risk of a one-grade increase in LOS was 2.84 times higher in the AKI group and the mortality of patients with AKI were higher. CONCLUSION: The incidence of AKI after hip fracture surgery was 12.1%. Advanced age, low BMI, and postoperative high level BNP were risk factors for AKI. Surgeons need to pay more attention to patients with older age, low BMI and high postoperative BNP levels in order to proactively prevent the development of postoperative AKI.