The prediction of early mortality following hip fracture surgery in patients aged 90 years and older: the Almelo Hip Fracture Score 90 (AHFS 90 )

Summary The AHFS 90 was developed for the prediction of early mortality in patients ≥ 90 years undergoing hip fracture surgery. The AHFS 90 has a good accuracy and in most risk categories a good calibration. In our study population, the AHFS 90 yielded a maximum prediction of early mortality of 64.5%. Purpose Identifying hip fracture patients with a high risk of early mortality after surgery could help make treatment decisions and information about the prognosis. This study aims to develop and validate a risk score for predicting early mortality in patients ≥ 90 years undergoing hip fracture surgery (AHFS 90 ). Methods Patients ≥ 90 years, surgically treated for a hip fracture, were included. A selection of possible predictors for mortality was made. Missing data were subjected to multiple imputations using chained equations. Logistic regression was performed to develop the AHFS 90 , which was internally and externally validated. Calibration was assessed using a calibration plot and comparing observed and predicted risks. Results One hundred and two of the 922 patients (11.1%) died ≤ 30 days following hip fracture surgery. The AHFS 90 includes age, gender, dementia, living in a nursing home, ASA score, and hemoglobin level as predictors for early mortality. The AHFS 90 had good accuracy (area under the curve 0.72 for geographic cross validation). Predicted risks correspond with observed risks of early mortality in four risk categories. In two risk categories, the AHFS 90 overestimates the risk. In one risk category, no mortality was observed; therefore, no analysis was possible. The AHFS 90 had a maximal prediction of early mortality of 64.5% in this study population. Conclusion The AHFS 90 accurately predicts early mortality after hip fracture surgery in patients ≥ 90 years of age. Predicted risks correspond to observed risks in most risk categories. In our study population, the AHFS 90 yielded a maximum prediction of early mortality of 64.5%.