Associations between baseline and longitudinal semi-automated quantitative joint space width at the hip and incident hip osteoarthritis: Data from a community-based cohort.

Objective To evaluate quantitative joint space width (qJSW, at 10-, 30-, and 50-degree locations) in relation to incident radiographic and symptomatic hip osteoarthritis (rHOA and sxHOA, respectively) in a community-based cohort. Methods Data were from Johnston County OA Project (JoCoOA) participants with supine hip radiographs at each of 4 timepoints; all had Kellgren-Lawrence grades (KLG) and qJSW. We assessed covariates (age, race, height, weight, body mass index [BMI]) associated with qJSW, and hip-level associations between qJSW and HOA, over time using sex-stratified and multivariable-adjusted linear mixed models. A cluster analysis with logistic regression estimated associations between qJSW trajectory groups and incident rHOA and sxHOA. Results At baseline, 397 participants (784 hips, 41% men, 24% Black, mean age=57 years) had a mean BMI=29 kilograms/meter2 . Over a mean of 18 years, 20% and 12% developed incident KLG-defined rHOA or sxHOA, respectively. QJSW was more sensitive to changes over time at 50 degrees. Values were stable among men but declined over time in women. Heavier women lost more qJSW; changes in qJSW were not significantly associated with race, education, or injury in women or men. In women only, loss of qJSW over time was associated with 2-3 times higher odds of rHOA and sxHOA; among women and men, narrower baseline qJSW was associated with these outcomes. Conclusion Hip qJSW demonstrates marked sex differences, with significant loss over time only in women. Loss of qJSW over time in women, and narrower baseline qJSW in men and women, was associated with incident rHOA and sxHOA.