Evaluation of Mortality Prediction Scales in Extracapsular Hip Fractures: A Retrospective Case-Control Study

Purpose: The aim of this study was to assess the reliability of various scales predictive of 30-day and 12-month postoperative mortality for patients with extracapsular hip fracture. Methods: A retrospective case-control study was designed including patients older than 65 years with extracapsular hip fracture, and matching patients who died within 12 months postoperatively with surviving patients. The Orthopaedic Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (O-POSSUM), Nottingham Hip Fracture Score (NHFS), Almelo Hip Fracture Score (AHFS) and SERNBO score were applied to the two groups, analysing the reliability, discriminative power and calibration of each of them. Results: 57 patients with 12-month mortality and 57 survivors were included, with a mean age of 86 years, 80.7% women. For 30-day postoperative mortality, the NHFS had the highest mean sensitivity (7.83%), while the AHFS showed the best specificity (95.23%). For 12-month postoperative mortality, the AHFS scale had the highest mean sensitivity (54.39%), and the NHFS had the best specificity (94.23%). Regarding calibration, the O-POSSUM, NHFS and AHFS scales overestimated 30-day and 12-month postoperative mortality. The scale with the best discriminative ability for 30-day mortality was SERNBO and AHFS (AUC 0.62-0.60), while NHFS had the best AUC for 12-month mortality (0.66). Conclusion: The AHFS and SERNBO scales are useful for predicting 30-day postoperative mortality, while the NHFS scale is a better choice for predicting 12-month mortality.