After screening with a 13C-urea breath test , they were randomized into three treatment arms : Helicobacter pylori-positive either to eradication therapy with OAM ( omeprazole , amoxycillin and metronidazole ) ( Hp + / erad ) or omeprazole 20 mg daily ( Hp + / ome ) for 10 days , whereas H. pylori-negative patients ( Hp - / ome ) were treated with 20 mg omeprazole for 10 days .
