Gluteus maximus cross-sectional area/density in 1-year mortality prediction for oldest-old hip fracture patients

Sarcopenia is a prevalent issue among older patients with hip fracture and is a risk factor for poor clinical outcomes. Computed tomography (CT)-derived muscle density and areawere reported to predict the prognosis of fracture patients. This study aimed to assess the efficacy of these CT-based muscle parameters in predicting 1-year mortality in the oldest-old patients with hip fracture (≥ 80 years). A retrospective study was conducted on 324 hip fracture patients aged ≥ 80 years from 2018 to 2022. The cross-sectional area (CSA) and Hounsfield units (HU) of periarticular hip muscles were measured from CT images. The primary outcome was 1-year mortality. A multivariate logistic regression model was constructed, and its performance was assessed using ROC analysis, calibration curves, and Hosmer-Lemeshow testing. A nomogram was developed for model visualization and early clinical application. The 1-year mortality rate in this cohort was 13.0% (42/324). Survivors and non-survivors significantly differed in age, red blood cells (RBC), platelets, albumin, urea, and gluteal muscle parameters (all P < 0.05). Multivariate analysis identified four mortality predictors: older age ( P = 0.048), lower albumin ( P = 0.025), reduced gluteal density ( P = 0.031), and smaller muscle area ( P = 0.045). Gluteus maximus density and area independently predicted 1-year mortality ( P < 0.05) in oldest-old hip fracture patients. Our predictive model incorporating age, muscle density, albumin, and muscle area showed a moderate predictive value (AUC = 0.741). This CT-based method offers a practical alternative to traditional sarcopenia assessments, facilitating early risk identification in this hip fracture population.