Incidence of symptomatic hand, hip, and knee osteoarthritis among patients in a health maintenance organization.

OBJECTIVE: To quantify the incidence of symptomatic hand, hip, and knee osteoarthritis (OA) among members of the Fallon Community Health Plan, a health maintenance organization located in central Massachusetts.

METHODS: Incident OA was defined as the first evidence of OA by radiography (grade > or = 2 on the Kellgren-Lawrence scale of 0-4) plus joint symptoms at the time the radiograph was obtained or up to 1 year before the radiograph was obtained.

RESULTS: The age- and sex-standardized incidence rate for hand OA was 100/100,000 person-years (95% confidence interval [95% CI] 86, 115), for hip OA 88/100,000 person-years (95% CI 75, 101), and for knee OA 240/100,000 person-years (95% CI 218, 262). The incidence of hand, hip, and knee OA increased with age, and women had higher rates than men, especially after age 50. A leveling off or decline occurred for both groups around the age of 80.

CONCLUSION: In a large study of symptomatic OA we observed incidence rates that increased with age. In women ages 70-89, the incidence of knee OA approached 1% per year.