A Simplified Endoscopic Grading Model for Gastric Intestinal Metaplasia With Preserved Diagnostic Accuracy

BACKGROUND: The endoscopic grading of gastric intestinal metaplasia (EGGIM) score enables real-time endoscopic assessment of the extent and severity of gastric intestinal metaplasia (IM) to guide surveillance. OBJECTIVE: We aimed to simplify the EGGIM system by identifying key gastric sites and evaluating simplified scoring approaches. METHODS: In this retrospective cohort study, patients undergoing gastric mapping during gastroscopy from 2022 to 2024 at a medical center were analyzed. EGGIM scoring was performed in real-time using high-resolution narrow-band imaging, with histopathological confirmation. We evaluated EGGIM-S, a simplified score based on the incisura angularis and the corpus lesser curvature. The diagnostic performance in predicting advanced IM (OLGIM Stage III/IV) was assessed and compared with the original EGGIM score. RESULTS: Among 942 patients undergoing mapping biopsies (56% female; median age 64 years), endoscopic IM involvement at the incisura angularis (odds ratio [OR] 1.75; p = 0.039) and the corpus lesser curvature (OR 2.54; p < 0.001) was independently associated with advanced histological stage, whereas involvement at the other sites was not. Combining these two sites, the AUROC was 0.829 for EGGIM-S and 0.828 for the original EGGIM, meeting the prespecified noninferiority margin (0.03; p = 0.0054). CONCLUSION: Intestinal metaplasia involving the corpus lesser curvature and the incisura angularis was significantly associated with advanced histological stage. A simplified two-site model (EGGIM-S) demonstrated comparable diagnostic performance, with the potential to improve efficiency and clinical applicability.