Nutritional Risk Scores and Cognitive Impairment After Hip Fracture: Strong Associations with Mortality but Limited Discriminative Performance

Background: Malnutrition and cognitive impairment are common in patients with proximal femur fractures and are associated with adverse outcomes. However, the prognostic performance of nutritional screening tools in this population remains uncertain. Methods: In this retrospective cohort study, 1595 patients aged ≥ 60 years undergoing surgery for proximal femur fracture were included. Nutritional status was assessed using seven established scores (MNA, PNI, GNRI, MUST, GMS, NRS-2002, CONUT). Mortality was evaluated at 30 days, 3 months, 6 months, 1 year, and 2 years. Associations were analysed using multivariable logistic regression adjusted for age, sex, ASA class, institutional residence, fracture type, and cognitive impairment. Discrimination was assessed using the area under the curve (AUC), and calibration was evaluated using calibration slopes and Brier scores. Results: Worsening nutritional status was consistently associated with increased mortality across all scores and timepoints. The strongest gradient was observed for MNA, with 2-year mortality increasing from 15.6% in patients with normal nutritional status to 53.8% in malnourished patients. Most scores remained independently associated with mortality after adjustment, with odds ratios per 1 SD deterioration ranging from 1.3 to 1.6. Discriminative performance was modest (AUC 0.57–0.69), with MNA showing the highest values. Differences between scores were small, with overlapping confidence intervals. Calibration was good across all models at 1 and 2 years. Conclusions: Nutritional status is independently associated with mortality after proximal femur fracture but provides limited discrimination for individual risk prediction. Nutritional scores may support identification of vulnerable patients but demonstrated limited performance for individual mortality prediction.