Age-stratified gradients of colorectal neoplasia and an exploratory endoscopic red-flag composite in a lesion-confirmed screening colonoscopy cohort

9OBJECTIVE: To characterise age-related gradients in colorectal lesion severity and prespecified high-risk endoscopic features in a lesion-confirmed screening colonoscopy cohort and to evaluate an investigator-defined red-flag composite as an exploratory marker of advanced pathology. Helicobacter pylori was assessed as a secondary exposure. METHODS: This retrospective cohort included 291 participants with histologically confirmed lesions in four age groups (36-45, 46-55, 56-65 and 66-72 years). Logistic regression evaluated predictors of advanced neoplasia (high-grade dysplasia [HGD] or adenocarcinoma); adenocarcinoma-only and age × H. pylori interaction analyses were exploratory because events were sparse. RESULTS: With advancing age, body mass index, H. pylori positivity, adenoma, sessile serrated lesions, HGD, adenocarcinoma and high-risk endoscopic features increased, whereas hyperplastic polyps decreased (all P < 0.05). Age (per 10 years), male sex, H. pylori positivity, lesion size ≥10 mm, proximal location and JNET 2B/3 pattern were independently associated with advanced neoplasia. Red-flag positivity (≥2 of four features) increased from 5.2% to 32.7% and enriched for adenocarcinoma, although positive predictive values were imprecise and non-monotonic. CONCLUSIONS: Colorectal lesion severity and high-risk endoscopic features showed an age-related gradient. The red-flag composite is an exploratory descriptive construct, not a validated predictive score. H. pylori findings, especially interaction analyses, are hypothesis-generating and require prospective validation.