The incidence of duodenal and gastric ulcers in a large health maintenance organization.

We report the incidence of peptic ulcers (duodenal, pyloric canal, gastric, and combined) verified by radiologic, endoscopic, or surgical evidence in a large Health Maintenance Organization (HMO) in Los Angeles, California. For members age 15 and above, the peptic ulcer incidence rate was 0.86 per 1,000 person-years (p-y) (males 1.10, females 0.63). The male to female sex ratio was 1.7. Two hundred twenty-two duodenal, 17 pyloric canal, 89 gastric, and 21 combined first-time diagnosed ulcer cases were located. For duodenal and pyloric canal ulcer, the incidence rate for members age 15 and above was 0.58 per 1,000 p-y (males 0.76, females 0.40). For gastric ulcer, the incidence rate for members age 15 and above was 0.21 per 1,000 p-y (males 0.23, females 0.18). The combined ulcer rate was 0.05 per 1,000 p-y (males 0.07, females 0.02). Gastric ulcer rates were two times higher in 1980 than in 1977. Peptic ulcer age-specific incidence rates increased with age. Incidence rates were much lower than those reported in previous studies, but the gastric to duodenal ulcer ratio and the age and sex relation to ulcer incidence were similar to those previously reported.