Prevalence and risk factors of gastric intestinal metaplasia: an International Classification of Diseases, 10th Revision-based study in an Iranian population

Gastric intestinal metaplasia (GIM) is a key precursor lesion to gastric cancer. Its early identification is essential for implementing timely surveillance and intervention strategies. Its prevalence and associated risk factors vary across populations. The use of International Classification of Diseases, 10th Revision (ICD-10) codes provides a standardized and stratified approach to classify GIM, enhancing the quality of epidemiologic studies. All consecutive upper endoscopic procedures with reflux-like symptoms or dyspepsia from a gastroenterology referral center in Tehran, Iran, between 1 March 2024 and 30 August 2024, were reviewed. Gastric biopsy pathology reports were retrieved using ICD-10 codes, and demographic and clinical data, including age, gender, and Helicobacter pylori infection status, were analyzed. Key outcomes were stratified using ICD-10 anatomical and dysplasia-related codes. Logistic regression models were employed to determine the association between GIM and potential risk factors. Among 4100 cases, the overall prevalence of GIM was 18.06%, with a higher occurrence in men (20.2%) compared with women (16.4%). Age was a significant risk factor, with individuals aged 70 and above having over nine times the odds of GIM compared to those under 30 [adjusted odds ratio (OR): 9.25, 95% confidence interval (CI): 5.4-15.8, P < 0.001]. H. pylori infection was more prevalent in patients with non-GIM (19.8%) compared to those with GIM (15.0%), suggesting an inverse association (adjusted OR: 0.78, 95% CI: 0.6-1.0, P = 0.025). The most common ICD-10 subtype was GIM without dysplasia in the antrum (69.55%), followed by body involvement (12.48%) and multiple-site GIM (12.75%). The lower prevalence of H. pylori in patients with GIM is most likely because of gastric atrophy, which is present in almost all patients with GIM. Early detection and stratification of GIM using ICD-10 codes may improve targeted surveillance and prevention of gastric cancer.