Muscle loss phenotype predicts poor postoperative outcomes of colorectal cancer in US inpatients: a population-based analysis.

PURPOSE: Muscle loss may lead to reduced therapy tolerance and survival. We aimed to assess whether colorectal cancer (CRC) patients with a muscle loss phenotype experience worse outcomes. METHODS: Data were extracted from the US Nationwide Inpatient Sample for hospitalized patients aged ≥20 years who underwent surgical resection for colorectal cancer (CRC) between 2005 and 2018. CRC and muscle loss phenotypes were identified using validated International Classification of Diseases (ICD) diagnosis and procedure codes. Propensity score matching was performed to balance characteristics. Regression analyses determined associations between muscle loss and in-hospital outcomes. RESULTS: A total of 209,171 patients were included, with a mean age of 67.9 years; 7.1% exhibited muscle loss phenotype. After matching, 60,295 patients remained in the sample. After adjustment, patients with muscle loss had significantly increased risks of postoperative complications (adjusted odds ratio [aOR], 2.99; 95% confidence interval [CI], 2.85-3.15), unfavorable discharge (aOR, 2.42; 95% CI, 2.30-2.53), prolonged length of stay (aOR, 4.34; 95% CI, 4.13-4.55), and higher total hospital costs (adjusted β, 70.86; 95% CI, 67.11-74.61) compared to patients without muscle loss. When stratified by age (≥65 years), results remained consistent. Among complications, muscle loss phenotype was most strongly associated with shock, sepsis, and respiratory failure. CONCLUSION: Muscle loss phenotype among patients with CRC is strongly associated with poor postoperative outcomes, including higher complication rates, longer stays, and increased costs. These findings highlight the importance of preoperative muscle loss assessments and the necessity for targeted interventions.