Metformin Efficacy and Safety for Gastric Intestinal Metaplasia

Inclusion Criteria: 1. Patients aged from 18 to 75 years old; 2. Body mass index (BMI) ranged from 18.5 to 23.9 at enrollment; 3. IM patients with OLGIM stage Ⅱ-Ⅲ diagnosed by upper gastrointestinal endoscopy and histopathological biopsy within the last 3 months; 4. Patients without H. pylori infection confirmed by 13C-urea breath test (UBT) or patients with H. pylori infection who completed the bismuth-containing quadruple program and had confirmed successful eradication by 13C-UBT. Exclusion Criteria: 1. History of diabetes mellitus (use of medication and/or HbA1c over 6.5%); 2. History of regular use (defined as at least once per week) of NSAIDs and/or aspirin; 3. History of stomach surgery (including endoscopic submucosal dissection and endoscopic mucosal resection) or previously diagnosed malignant tumor; 4. History of heart failure, renal failure, liver cirrhosis or chronic hepatic failure; 5. Patients with contraindications or allergies to the drugs in this study; 6. Breastfeeding or pregnancy; 7. History of substance abuse or alcohol abuse in the past 1 year; 8. Severe mental illness; 9. Refusal of drug treatment; 10. Refusal of signing informed consent.