Abstract
BACKGROUND: Allostatic load (AL) is a composite measure of the physiological damage caused by socioenvironmental stressors. We sought to investigate the association between AL, social vulnerability index (SVI), and postoperative outcomes following colorectal cancer (CRC) surgery. PATIENTS AND METHODS: Individuals who underwent surgery for CRC between 2022 and 2024 were identified using the Epic Cosmos database. AL is calculated on the basis of ten biomarkers from four physiological systems (cardiovascular, metabolic, renal, immune). Multivariable regression models were utilized to examine the association between AL and postoperative outcomes. RESULTS: Among 40,520 individuals, mean patient age was 67.7 years (SD ±13.9), roughly half of the patients were male (n = 20,573; 50.8%), and patients generally had a high Charlson comorbidity index score (CCI > 2; n = 33,132; 81.8%). Overall, 7.1% (n = 2897) of patients had a high AL. Notably, AL increased with increasing SVI (ref: low; medium: 1.10 [95% CI 1.01-1.20]; high: 1.17 [95% CI 1.07-1.28]). High AL was associated with a 48% increased risk of postoperative complications (OR 1.48; 95% CI 1.38-1.58), a 79% increased risk of an extended length of stay (OR 1.79; 95% CI 1.67-1.90), and a twofold (OR 2.13; 95% CI 1.90-2.37) increase in the risk of mortality within 30 days of surgery. CONCLUSIONS: Individuals with CRC living in socially vulnerable neighborhoods experience high physiological damage and are at a higher risk of postoperative complications and mortality. Therefore, patients from socially vulnerable neighborhoods may require preoperative screening and optimization to mitigate disparities in surgical outcomes.