Lack of effect of treating Helicobacter pylori infection in patients with nonulcer dyspepsia. Omeprazole plus Clarithromycin and Amoxicillin Effect One Year after Treatment (OCAY) Study Group

N Engl J Med. 1998 Dec 24;339(26):1875-81. doi: 10.1056/NEJM199812243392602.


Background: It is uncertain whether treatment of Helicobacter pylori infection relieves symptoms in patients with nonulcer, or functional, dyspepsia.

Methods: We conducted a double-blind, multicenter trial of patients with H. pylori infection and dyspeptic symptoms (moderate-to-very-severe pain and discomfort centered in the upper abdomen). Patients were excluded if they had a history of peptic ulcer disease or gastroesophageal reflux disease and had abnormal findings on upper endoscopy. Patients were randomly assigned to seven days of treatment with 20 mg of omeprazole twice daily, 1000 mg of amoxicillin twice daily, and 500 mg of clarithromycin twice daily or with omeprazole alone and then followed up for one year. Treatment success was defined as the absence of dyspeptic symptoms or the presence of minimal symptoms on any of the 7 days preceding the 12-month visit.

Results: Twenty of the 348 patients were excluded after randomization because they were not infected with H. pylori, were not treated, or had no data available. For the remaining 328 patients (164 in each group), treatment was successful for 27.4 percent of those assigned to receive omeprazole and antibiotics and 20.7 percent of those assigned to receive omeprazole alone (P=0.17; absolute difference between groups, 6.7 percent; 95 percent confidence interval, -2.6 to 16.0). After 12 months, gastritis had healed in 75.0 percent of the patients in the group given omeprazole and antibiotics and in 3.0 percent of the patients in the omeprazole group (P<0.001); the respective rates of H. pylori eradication were 79 percent and 2 percent. In the group given omeprazole and antibiotics, the rate of treatment success among patients with persistent H. pylori infection was similar to that among patients in whom the infection was eradicated (26 percent vs. 31 percent). There were no significant differences between the groups in the quality of life after treatment.

Conclusions: In patients with nonulcer dyspepsia, the eradication of H. pylori infection is not likely to relieve symptoms.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Amoxicillin / therapeutic use*
  • Anti-Bacterial Agents / therapeutic use*
  • Anti-Ulcer Agents / therapeutic use*
  • Clarithromycin / therapeutic use*
  • Double-Blind Method
  • Drug Therapy, Combination
  • Dyspepsia / drug therapy*
  • Dyspepsia / microbiology
  • Female
  • Helicobacter Infections / drug therapy*
  • Helicobacter pylori*
  • Humans
  • Male
  • Middle Aged
  • Omeprazole / therapeutic use*
  • Quality of Life
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Anti-Ulcer Agents
  • Amoxicillin
  • Clarithromycin
  • Omeprazole