Validation of the nottingham hip fracture score (Nhfs) in patients with hip fracture: A prospective cohort study in the Netherlands

Abstract

Introduction: The Nottingham Hip Fracture Score (NHFS) was developed to predict 30-day mortality for patients with hip fracture. This study aimed to validate the NHFS in a cohort with sufficient statistical power. Methods: Data were extracted from a prospective hip-fracture database (FAMMI). Patients were included between January 1, 2018 and January 11, 2021. All consecutively admitted patients ≥18 years of age with a hip fracture (ie, femoral neck fracture, intertrochanteric fracture, and subtrochanteric fracture) were included. Mann–Whitney’s U values were cal-culated to find potential miscalibration of the NHFS formula. Discrimination evaluation was performed using the concordance statistic as an equivalent to area under the receiver-operating curve. Results: In total, 2,458 patients were included. Mean age was 80±12 years, and 66% were women (n=1,631). Median NHFS was 5 (4–6) and overall 30-day mortality 7.9% (n=195). Overall goodness of fit was tested with Pearson’s ?2 (11.8, df 10; P=0.297). No statistically significant signs of miscalibration were found (Mann–Whitney U, P=0.08). Discrimination was tested with area under the receiver-operating curve, which was 72.1% (95% CI 68.7%– 75.4%). However, observed 30-day mortality in our population of hip-fracture patients was slightly higher than the NHFS prediction. Conclusion: The NHFS seemed to predict 30-day mortality with reasonable accuracy for patients with a hip fracture in a population within the Netherlands.