Association of systemic inflammatory indices with gastrointestinal tumors: evidence from NHANES and a hospital-based cohort.

BACKGROUND: Systemic inflammation plays an important role in tumor development and progression. Several inflammation-related indices derived from routine blood tests have been proposed as potential biomarkers for cancer. However, their associations with gastrointestinal tumors in large population-based datasets remain insufficiently explored. METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) were used to examine the associations between nine systemic inflammatory indices and gastrointestinal tumors. Multivariable logistic regression, propensity score matching, and restricted cubic spline analyses were performed. Mortality-linked NHANES data were further analyzed using Cox regression and Kaplan-Meier methods. An independent hospital-based cohort was used to validate the main findings. RESULTS: Several systemic inflammatory indices were significantly associated with gastrointestinal tumor status in NHANES. NLR and RAR showed particularly strong associations and ranked among the most influential variables in the machine-learning analyses. Restricted cubic spline analyses indicated nonlinear association patterns, with higher NLR and RAR levels corresponding to greater odds of gastrointestinal tumors. The main findings remained generally consistent in the propensity score-matched cohort. In the hospital-based cohort, patients with gastrointestinal tumors also showed higher systemic inflammatory levels than healthy controls. A nomogram incorporating CALLY, NLR, RAR, and clinical variables demonstrated good discriminative performance, with an AUC of 0.852. In addition, several baseline inflammatory indices were independently associated with all-cause mortality among patients with gastrointestinal tumors. CONCLUSION: Systemic inflammatory indices derived from routine blood tests were associated with gastrointestinal tumor status and all-cause mortality. These main findings were further supported by the hospital-based cohort. Routine inflammation-related indices may therefore provide useful information for identifying tumor-associated inflammatory changes and evaluating prognosis in patients with gastrointestinal tumors.