title: CT of Patients With Hip Fracture: Muscle Size and Attenuation Help Predict Mortality.
abstract: OBJECTIVE
  Our objective was to determine the association between muscle cross-sectional area and attenuation, as measured on routine CT scans, and mortality in older patients with hip fracture.
  
  
  METHODS
  A retrospective 10-year study of patients with hip fracture was conducted with the following inclusion criteria: age 65 years or older, first-time hip fracture treated with surgery, and CT of the chest, abdomen, or pelvis. This yielded 274 patients (70.4% women; mean [± SD] age, 81.3 ± 8.3 years). On each CT scan, two readers independently measured the size (cross-sectional area, indexed for patient height) and attenuation of the paravertebral muscle at T12 and the psoas muscle at L4. We then determined the association between overall mortality and the muscle size and muscle attenuation, while adjusting for demographic variables (age, sex, ethnicity, and body mass index), American Society of Anesthesiologists (ASA) classification, and Charlson comorbidity index (CCI).
  
  
  RESULTS
  The overall mortality rate increased from 28.3% at 1 year to 79.5% at 5 years. Mortality was associated with decreased thoracic muscle size (odds ratio [OR], 0.66; 95% CI, 0.49-0.87). This association persisted after adjusting for demographic variables (OR, 0.69; 95% CI, 0.50-0.95), the ASA classification (OR, 0.70; CI, 0.51-0.97), and the CCI (OR, 0.72; 95% CI, 0.52-1.00). Similarly, decreased survival was associated with decreased thoracic muscle attenuation after adjusting for all of these combinations of covariates (OR, 0.67-0.72; 95% CI, 0.49-0.99). Decreased lumbar muscle size and attenuation trended with decreased survival but did not reach statistical significance.
  
  
  CONCLUSIONS
  In older adults with hip fractures, CT findings of decreased thoracic paravertebral muscle size and attenuation are associated with decreased overall survival.
authors.affiliation: 1 Department of Radiology, University of California Davis School of Medicine, 4860 Y St, Ste 3100, Sacramento, CA 95817.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Boutin
authors.affiliation: 1 Department of Radiology, University of California Davis School of Medicine, 4860 Y St, Ste 3100, Sacramento, CA 95817.
authors.forename: Sara
authors.initials: S
authors.lastname: Bamrungchart
authors.affiliation: 1 Department of Radiology, University of California Davis School of Medicine, 4860 Y St, Ste 3100, Sacramento, CA 95817.
authors.forename: Cyrus P
authors.initials: CP
authors.lastname: Bateni
authors.affiliation: 2 Department of Biostatistical Sciences, Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Beavers
authors.affiliation: 3 Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC.
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Beavers
authors.affiliation: 4 Department of Orthopaedic Surgery, University of California Davis School of Medicine, Sacramento, CA.
authors.forename: John P
authors.initials: JP
authors.lastname: Meehan
authors.affiliation: 5 Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC.
authors.forename: Leon
authors.initials: L
authors.lastname: Lenchik
mesh_terms: D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D015984:Causality; D015897:Comorbidity; D005260:Female; D006620:Hip Fractures / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000601:surgery; D006801:Humans; D008297:Male; D009929:Organ Size; D015995:Prevalence; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D055948:Sarcopenia / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000601:surgery; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
keywords: CT; hip fracture; mortality; muscle; sarcopenia