A 50-year-old man presents with a 3-month history of intermittent epigastric pain, typically worse 2-3 hours after meals and often waking him at night. He reports some relief with over-the-counter antacids. He is a smoker and drinks 20 units of alcohol per week. He is H. pylori negative on a stool antigen test performed last month. What is the most appropriate next step in management?