Muscle Abnormalities in Colorectal Cancer: Exploring the Associations of Muscle Abnormalities with Pre-existing Comorbidities, and Adverse Surgical Outcomes in Non-metastatic Colorectal Cancer Patients

• Author / Creator

  Jingjie Xiao

• The aim of this project was to further understand the association of pre-existing comorbidities and adverse surgical outcomes with muscle abnormalities in patients with non-metastatic colorectal cancer (CRC). Computerized tomographpy (CT) imaging was used for body composition assessment, and patients’ electronic medical records were searched for demographics, pre-existing comorbidities, and surgical outcomes. Muscle abnormalities were defined as sarcopenia [i.e. low skeletal muscle mass index (SMI)] and/or low skeletal muscle radiodensity (SMD). In study 1, demographic, clinical variables and body composition measures were obtained for 3,262 patients. Advanced age was a significant predictor for both sarcopenia and low SMD. Compared with patients ≤50 years, those with 70-80 years had an increased risk for presenting with sarcopenia (OR=5.79, 95% CI 4.45-7.52), and with low SMD (OR=17.29, 95% CI 11.42-26.16). Higher amounts of total adipose tissue predicted a higher likelihood of low SMD (OR=8.52, 95% CI 6.59-11.01), but a lower likelihood of sarcopenia (OR=0.56, 95% CI 0.46-0.67). A significant variability in SMI and SMD across age, sex, body mass index (BMI) and race/ethnicity groups was observed. In study 2, International Classification of Disease-9 diagnostic codes for Charlson’s comorbidities were obtained from all inpatient and outpatient encounters in the year prior to CRC diagnosis, in 3,051 patients. Multivariable logistic regressions identified six comorbidities predictive of low SMD, including myocardial infarction (OR=1.77, 95% CI 1.08-2.88), congestive heart failure (OR=3.27, 95% CI 1.97-5.41), peripheral vascular disease (OR=2.15, 95% CI 1.33-3.47), diabetes with (OR=1.61, 95% CI 1.13-2.29) or without (OR=1.46, 95% CI 1.13-1.89) complications, and renal disease (OR=2.21, 95% CI 1.50- 3.25), whereas only diabetes with complications predicted a lower likelihood of sarcopenia (OR=0.64, 95% CI 0.47-0.89). In study 3, data on post-surgical length of hospital stay (LOS), any complication, mortality and readmission up to 30 days post-surgery or post-discharge were obtained for n=1,715 colon cancer patients who underwent resection surgery. Sarcopenia and low SMD were each associated with longer LOS (OR=1.30, 95% CI 1.03-1.63 and OR=1.42, 95% CI 1.08-1.86, respectively). Sarcopenia was additionally associated with a higher risk of postoperative complications (OR=1.26, 95% CI 1.02-1.55) and mortality (OR=3.85, 95% CI 1.14-13.04). The additive effect of sarcopenia and low SMD was even stronger for longer LOS (OR=1.84, 95% CI 1.34-2.54) and 30-day mortality (OR=9.68, 95% CI 2.05-45.72) compared to the independent effects of each muscle abnormality. These studies demonstrated a high prevalence and great variability of muscle abnormalities among age, sex, BMI and race/ethnicity groups in patients with non-metastatic CRC. The findings of multiple pre-existing comorbidities associating with low SMD suggested a potential shared mechanism between fat infiltration into muscle and each of these comorbidities. The impact of muscle abnormalities on adverse surgical outcomes highlights the need of integrating body composition evaluation for patient risk stratification. These findings can be translated into healthcare improvement for patients with CRC.

• Subjects / Keywords

  • Charlson comorbidities
  • Muscle abnormalities
  • Surgical outcomes
  • Colorectal cancer

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3KK94T38

• License

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