Lower muscle density is associated with major postoperative complications in older patients after surgery for colorectal cancer

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/mm² for males and 26.3 ± 5.0 HU/mm² for females. The cut-off point for the lowest gender specific quartile was ≤22.0 HU/mm² for males and ≤23.5 HU/mm² for 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.

Conclusion: Low muscle density is associated with major postoperative complications in older patients who undergo surgery for colorectal cancer.