Duodenal ulcers and benign stomach ulcers are frequently referred to as peptic ulcers. Peptic ulcers are among the digestive diseases with the highest incidence. Approximately 10% of the population experience a peptic ulcer at some point in their life, though a substantial proportion, perhaps a majority, are not medically diagnosed. Peptic ulcers generally heal even without prescribed treatment in 4 to 6 weeks. Approximately 1% of those with peptic ulcers experience complications, with potentially life-threatening perforation of the stomach or duodenum being the more serious complications. The disease often recurs, with a probability of recurrence in the range of 50%.
For many years, peptic ulcers were believed to be exclusively the result of excess acid production due to such factors as alcohol, aspirin and other anti-inflammatory medications, spicy foods, and stress. The stomach and duodenum were known to be highly acidic, and it was believed that bacteria were unable to survive in this high-acid environment.
In the early 1980s, investigators observed a spiral-shaped bacterium, which they named Helicobacter pylori, or H. pylori, in a number of pathological specimens from patients with disease of the stomach and duodenum. Most scientists doubted the relationship to disease, often concluding that the organism must be a contaminant because of the belief that bacteria could not grow in highly acidic environments.
After many unsuccessful attempts, Australian researchers Barry J. Marshall, MD, and J. Robin Warren, MD, were able to culture the bacteria from the stomach and became convinced that the bacteria were actually the cause of peptic ulcers. They were frustrated in their attempts to demonstrate that H. pylori was the cause of the disease because of the absence of good animal models. To attempt to establish causation, Marshall drank a flask of the cultured bacteria. He became ill and developed acute ulceration of the stomach. H. pylori was cultured from his ulcerations. This dramatic effort brought attention and extensive investigations to address whether H. pylori is a contributory cause of duodenal ulcers.
Subsequent studies in the United States and other countries established that H. pylori is a frequently occurring organism that increases with increasing age. Overall, over 20% of people in the United States have H. pylori, that is its prevalence is over 20% in the United States, with a higher prevalence beginning at an early age in many developing countries, as well as Japan. In case-control studies, H. pylori was found to have a strong association with duodenal ulcer, with over 70% of peptic ulcer patients having H. pylori at the time of their diagnosis.
Randomized controlled trials examined the recurrence rates of duodenal ulcers after treatment of the bacteria with antibiotics shown to eliminate H. pylori. In one study among those randomized to placebo, the recurrence rate was over 10 times as great as among those randomized to antibiotic treatment directed against H. pylori. This research led to a search for biological mechanisms. Extensive research established a greater understanding of the physiology of peptic ulcers, including identifying the production of an enzyme by H. pylori that reduces acidity and thus facilitates its growth in an acid environment.
New tests demonstrated that H. pylori is associated with the great majority of duodenal ulcers among outpatients. Randomized controlled trials and extensive clinical follow-up established the effectiveness and relative safety of antibiotic treatments of H. pylori. These investigations led to evidence-based recommendations for routine testing for H. pylori among outpatients diagnosed with peptic ulcers and treatment of H. pylori with antibiotics when it was detected.