Age-dependent effects of gastric cancer screening endoscopy on mortality: a nationwide cohort study

Background: Endoscopic screening for gastric cancer reduces mortality, but the optimal upper age limit and modifying role of comorbidity remain unclear. Methods: This nationwide retrospective cohort study used the Korean National Health Insurance Service database linked to national mortality records. Individuals aged ≥40 years who underwent screening esophagogastroduodenoscopy between 2005 and 2010 were included and propensity score-matched to non-screened controls. The primary outcome was gastric cancer-specific mortality. Comorbidity was assessed using the Charlson Comorbidity Index (CCI). Hazard ratios (HRs) were estimated in the matched cohort. Results: Among 555 904 propensity score-matched individuals (277 952 per group), gastric cancer-specific mortality HRs showed an age-dependent gradient: