HIP OSTEOARTHRITIS PREVALENCE ESTIMATES BY 3 RADIOGRAPHIC SCORING SYSTEMS

Objective. To estimate and compare the age- and sex-specific prevalenc e of radiographic hip osteoarthritis (RHOA) in a population-based stud y of the Pima Indians, using 3 atlas-based methods for assessing featu res of RHOA. Methods. Pelvic radiographs from 755 Pima Indians age gre ater than or equal to 45 years enrolled in a population-based study we re read using the Kellgren/Lawrence (K/L) grading scale (grade 0-4) an d 2 validated individual-radiographic-features (IRF) scales (grades 0- 3 for narrowing and osteophytes), Results. The age- and sex-specific p revalence of RHOA among Pima Indians assessed using the K/L scale was <10% in all age and sex groups. The prevalence of grade 12 osteophytes assessed using the 2 IRF scales were similar to each other in all age and sex groups. However, differences between the 2 IRF scoring system s were found for the prevalence of grade greater than or equal to 2 jo int space narrowing. Conclusion. Pima Indians have an age-and sex-spec ific prevalence of RHOA similar to that found in the US population. Ou r finding of different joint space narrowing prevalence by the 2 IRF g rading scales supports the use of the same atlas-based case definition s for determining disease prevalence for comparative studies.