Sex-Specific Body Composition Profile Determined by Pelvic Computed Tomography Associated with Mortality in Older Patients with Hip Fracture

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Objectives Previous research has demonstrated notable differences in body composition and mortality risk following hip fracture between sexes. This study aimed to investigate the sex-specific associations between body composition profile and mortality in older patients undergoing hip fracture surgery. Design Dual-center cohort study. Setting and Participants We included 488 older patients (aged ≥60 years) with hip fracture treated with surgery. Methods The cross-sectional area and attenuation of skeletal muscle, subcutaneous adipose tissue, and intermuscular adipose tissue at the the upper thigh level on preoperative pelvic computed tomography (CT) were measured. The relationship between body composition and mortality was determined using Cox proportional hazards analysis stratified by sex. Results The mean age of the cohort was 76.2 ± 8.7 years, and 312 (63.9%) were women. Within 1 year after surgery, 89 (18.2%) patients died. Female patients had greater subcutaneous adipose tissue area [SATA; median (interquartile range), 196.5 (160.1∼228.5) vs 147.1 (111.3∼181.1) cm 2 ; P < .001] and lower skeletal muscle area [SMA; 187.2 (167.3∼212.4) vs 255.5 (223.2∼286.1) cm 2 ; P < .001] compared with male patients. In the sex-stratified multivariable analyses, SATA in females [hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.86∼0.97; P = .003] and SMA in men (HR, 0.93; 95% CI, 0.86∼1.00; P = .05) were significant predictors of 1-year mortality. Incorporation of SATA or SMA within the existing Nottingham Hip Fracture Score (NHFS) showed slightly improved performance in predicting 1-year mortality among women [area under the curve (AUC), 0.70 vs 0.64, P = .11] or men (AUC, 0.76 vs 0.71, P = .06), respectively. Conclusions and Implications Reduced subcutaneous adiposity is associated with mortality in older women undergoing hip fracture surgery, while reduced muscle mass predicts mortality in men. These findings highlight the importance of considering sexual dimorphism in the development of novel biomarkers and effective treatment strategies.