HELICOBACTER-PYLORI INFECTION AS A CAUSE OF GASTRITIS, DUODENAL-ULCER, GASTRIC-CANCER AND NONULCER DYSPEPSIA - A SYSTEMATIC OVERVIEW

Objective: To evaluate current evidence for a causal relation between Helicobacter pylori infection and gastritis, duodenal ulcer, gastric c ancer and nonulcer dyspepsia. Data sources: A MEDLINE search for artic les published in English between January 1983 and December 1992 with t he use of MeSH terms Helicobacter pylori, gastritis, duodenal ulcer, g astric cancer, dyspepsia and clinical trial; abstracts were excluded. Six journals and Current Contents were searched manually for pertinent articles published in that time frame. Study selection: Original stud ies with at least 25 patients, case reports and reviews that examined the relation between H. pylori and the four gastrointestinal disorders ; 350 articles were on gastritis, 122 on duodenal ulcer, 44 on gastric cancer and 96 on nonulcer dyspepsia. Data extraction: The quality of the studies was rated independently on a four-point scale. The strengt h of the evidence was assessed using a six-point scale for each of the eight established guidelines for determining a causal relation. Data synthesis: There was conclusive evidence of a causal relation between H. pylori infection and histologic gastritis. Koch's postulates for th e identification of a microorganism as the causative agent of a diseas e were fulfilled for H. pylori as a causative agent of gastritis. Ther e was strong evidence that H. pylori is the main cause of duodenal ulc ers not induced by nonsteroidal anti-inflammatory drugs, but all of Ko ch's postulates were not fulfilled. There was moderate epidemiologic e vidence of an association between chronic H. pylori infection and gast ric cancer. There was a lack of convincing evidence of a causal associ ation between H. pylori and nonulcer dyspepsia. Conclusions: The evide nce supports a strong causal relation between H. pylori infection and gastritis and duodenal ulcer and a moderate relation between such infe ction and gastric cancer. Further studies are needed to clarify the ro le of H. pylori in these disorders. Thus far, there is no evidence of a causal relation between H. pylori and nonulcer dyspepsia.