title: Lower muscle density is associated with major postoperative complications in older patients after surgery for colorectal cancer.
abstract: BACKGROUND
  Reduced muscle density is associated with an increased risk of postoperative complications. We examined the prognostic value of muscle density as a predictor of postoperative complications in elderly patients undergoing surgery for colorectal cancer.
  
  
  METHODS
  Patients (≥70 years) who underwent surgery for colorectal cancer between 2006 and 2013 were selected from a prospective single centre database. The Hounsfield Unit Average (HUA or HU/mm2) of the psoas muscles at the level of the third lumbar vertebra was calculated on the scan. High and low muscle density groups were identified based on the lowest gender specific HUAC quartile. Major postoperative complications (Clavien-Dindo (CD) ≥3) within 30 days after surgery were retrospectively documented. Logistic regression analysis was used to identify risk factors for postoperative complications.
  
  
  RESULTS
  A total of 373 patients (median age = 78 years) were included in this study. The mean muscle density score was 24.5 ± 4.3 HU/mm2for males and 26.3 ± 5.0 HU/mm2for females. The cut-off point for the lowest gender specific quartile was ≤22.0 HU/mm2for males and ≤23.5 HU/mm2for females. After multivariable regression, there was a statistically significant association between muscle density and CD ≥ 3 (OR = 1.84 (95% CI 1.11-3.06), p = 0.019). Anastomotic leakage in patients with a primary anastomosis (n = 287) occurred more often in patients with low muscle density (11.7% vs 23.3%, p = 0.016). The associations remained significant after correction for confounders.
  
  
  CONCLUSIONS
  Low muscle density is associated with major postoperative complications in older patients who undergo surgery for colorectal cancer.
authors.affiliation: Department of Surgery, Gelre Hospitals, Apeldoorn, The Netherlands.
authors.forename: C C
authors.initials: CC
authors.lastname: Margadant
authors.affiliation: Department of Surgery, Gelre Hospitals, Apeldoorn, The Netherlands; Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: E R J
authors.initials: ER
authors.lastname: Bruns
authors.affiliation: Department of Surgery, Gelre Hospitals, Apeldoorn, The Netherlands; Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands. Electronic address: sloothaak.didi@gmail.com.
authors.forename: D A M
authors.initials: DA
authors.lastname: Sloothaak
authors.affiliation: Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: van Duijvendijk
authors.affiliation: Department of Radiology, Gelre Hospitals, Apeldoorn, The Netherlands.
authors.forename: A F
authors.initials: AF
authors.lastname: van Raamt
authors.affiliation: Department of Epidemiology, Gelre Hospitals, Apeldoorn, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: van der Zaag
authors.affiliation: Department of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: C J
authors.initials: CJ
authors.lastname: Buskens
authors.affiliation: Department of Medicine, University Medical Centre, Groningen, The Netherlands; Department of Geriatrics, Gelre Hospitals, Apeldoorn, The Netherlands.
authors.forename: B C
authors.initials: BC
authors.lastname: van Munster
authors.affiliation: Department of Surgery, Gelre Hospitals, Apeldoorn, The Netherlands.
authors.forename: E S
authors.initials: ES
authors.lastname: van der Zaag
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D011183:Postoperative Complications / Q000209:etiology*; D055948:Sarcopenia / Q000209:etiology
keywords: Colorectal cancer; Muscle density; Older adults; Postoperative complications; Surgery