Objective To explore the predictive value of the pre-injury Barthel index (BI) for 1-year postoperative case fatality rate after hip arthroplasty in elderly patients with hip fracture, and to determine its optimal cut-off value. Methods A retrospective cohort study was conducted. Elderly patients with hip fracture who underwent hip arthroplasty and met the selection criteria between January 1, 2020 and December 31, 2022 were enrolled. General baseline data [age, gender, body mass index (BMI), comorbidities including diabetes and hypertension, medical history including malignancy and thrombosis, and smoking history], clinical indicators (preoperative hemoglobin level, operation duration, postoperative venous thrombosis), pre-admission and pre-injury BI, as well as 1-year postoperative survival outcomes were collected. logistic regression analysis was used to identify risk factors for 1-year postoperative fatality, and receiver operating characteristic curve analysis was performed to determine the optimal cut-off value of pre-injury BI for predicting postoperative fatality. Results A total of 584 patients were enrolled, including 182 males and 402 females, with a mean age of 78.6 years (range, 65-99 years). Sixty-one patients died within 1 year after operation, with a 1-year postoperative case fatality rate of 10.45%. logistic regression analysis showed that age was an independent risk factor for 1-year postoperative fatality (OR=1.138, P=0.002), while pre-injury BI was an independent protective factor (OR=0.972, P=0.008). BMI, preoperative hemoglobin level, and operation duration had no independent predictive significance (P>0.05). The area under the curve of pre-injury BI for predicting 1-year postoperative fatality was 0.794 (95%CI: 0.754, 0.835; P<0.001), with a sensitivity of 0.61, a specificity of 0.98, and the optimal cut-off value of 80. According to the cut-off value, there were 263 patients with pre-injury BI≤80 and 321 patients with pre-injury BI>80. The 1-year postoperative case fatality rates of the two groups were 22.81% and 0.31%, respectively, and the difference was significant (χ2=78.251, P<0.001). Conclusion Pre-injury BI is a reliable predictive factor for 1-year postoperative fatality after hip arthroplasty in elderly patients with hip fracture. It is recommended that pre-injury BI assessment should be included in routine admission evaluation. For patients with pre-injury BI<80, intensified management and multidisciplinary intervention should be implemented to improve postoperative prognosis.
