Helicobacter pylori infection, ABO blood group, and effect of misoprostol on gastroduodenal mucosa in NSAID-treated patients with rheumatoid arthritis.

Our aim was to investigate the effect of misoprostol on NSAID-induced gastroduodenal mucosal damage in patients with rheumatoid arthritis. The study included 40 patients, and it was designed as a double-blind, placebo-controlled trial. Misoprostol significantly reduced the gastroduodenal mucosal lesions found at endoscopy (P < 0.05) and prevented the development of ulcers. The cumulative incidence of ulcers at four weeks was 5% in the placebo group and 0% in the misoprostol group. The basal and pentagastrin-stimulated acid output as evaluated after 23 days of treatment with misoprostol was not significantly affected. Forty-one percent of the patients had signs of current Helicobacter pylori infection, 33% had positive serology only, and 26% had no evidence of infection. Most of the patients with current infection belonged to blood group O (P < 0.05). Misoprostol treatment did not affect the occurrence of Helicobacter pylori or the rheumatic disease activity. It is concluded that the protective actions of misoprostol on the gastroduodenal mucosa of NSAID-treated patients are largely mediated by mechanisms other than inhibition of acid secretion. The relationship among active Helicobacter pylori infection, blood group O, and peptic ulcer may be helpful to identify a subpopulation of patients taking NSAIDs at risk of developing peptic ulcers.