RESUMEN
Infection with Helicobacter pylori (H. pylori) is highly prevalent in Chile, but there are no systematic studies in patients with upper gastrointestinal symptoms. Aim: To determine the prevalence of H. pylori infection, according to age, gender and endoscopic pathology in a large sample of patients. Methods: We studied 7,893 symptomatic patients submitted to upper gastrointestinal endoscopy between July 1996 and December 2003 in the context of a screening program of gastric cancer in a high risk population. H. pylori infection was determined by rapid urease test (RUT) in antral mucosa. We excluded 158 patients with gastric cancer (2 percent) and 2,071 patients without RUT. Results: We included 5,664 patients, mean age 50.7 ± 13.9 years, women 72.1 percent. Endoscopic diagnoses were normal in 59.3 percent, erosive esophagitis in 20 percent, gastric ulcer (GU) in 8.1 percent, duodenal ulcer (DU) in 6.4 percent, and erosive gastropathy in 6.2 percent. RUT was positive in 78 percent of patients. After adjusting for age and sex and with respect to patients with normal endoscopy, frequency of H. pylori infection was 86.6 percent in DU (OR 2.1, 95 percent CI 1.5-2.8, p < 0.001); 81.4 percent in GU (OR 1.8, 95 percent CI 1.4-2.4; p < 0.001 ); 79.9 percent in erosive gastropathy (OR 1.4, 95 percent CI 1.03-1.8; p = 0.03) and 77.4 percent in erosive esophagitis (OR 1.1, 95 percent CI: 0.9-1.3; p = NS). The probability of H. pylori infection decreased significantly with age, more markedly in men with normal endoscopy. Conclusions: Prevalence of H. pylori infection is very high in symptomatic Chilean patients and even higher in those with gastroduodenal ulcer or erosions, while in patients with erosive esophagitis is similar to those with normal endoscopy. The frequency of infection decreases with age, probably as a consequence of rising frequency of gastric mucosal atrophy.