Objective: To describe progression over 8 years in a community-based sample of elderly women with radiographic findings of hip osteoarthritis (RHOA) with or without hip pain.
Methods: Baseline and followup anteroposterior pelvic radiographs were obtained at a mean +/- SD 8.3 +/- 0.4 years of followup in women age > or =65 years at the baseline examination of the Study of Osteoporotic Fractures. We evaluated progression in 936 hips of 745 women with one or more baseline findings of RHOA: summary OA grade > or =2, minimum joint space (MJS) < or =1.5 mm, definite femoral or acetabular osteophytes, definite superolateral joint space narrowing (JSN), or moderate or worse superomedial JSN. We separately examined progression in hips with an MJS between 1.5 mm and 2.5 mm. Hip pain and lower extremity disability were assessed by questionnaire and examination. Measures of progression included an increase in summary grade of radiographic findings, increase in total osteophyte score, decrease in MJS of > or =0.5 mm, total hip replacement (THR), and increase in lower extremity disability score. Odds ratios (ORs) and 95% confidence intervals (95% CIs) for baseline radiographic predictors of progression were estimated using general estimating equations.
Results: During followup, 12.9% of women with baseline RHOA underwent THR, and 22.8% had substantial worsening of lower extremity disability, while 64.6% of hips with RHOA showed radiographic progression or were replaced. Progression was greater by all measures in the 37% of hips and 47% of women with both RHOA and hip pain at baseline. Of hips with pain, 23.6% progressed to THR compared with 2.7% of hips without pain (OR 8.1 [95% CI 4.2, 15.4], P < 0.001), and MJS decreased > or =0.5 mm in 53.7% of hips with pain compared with 30.7% of hips without pain (OR 1.9 [95% CI 1.4, 2.6], P < 0.001). Women with hip pain were more likely to have worsened lower extremity disability (29.3% versus 17.6%; OR 1.8 [95% CI 1.2, 2.8], P = 0.0053). Hips with an MJS >1.5 mm and < or =2.5 mm (n = 1,868) had primarily superomedial narrowing and comparatively low rates of progression that did not differ by hip pain. Femoral osteophytes, superolateral JSN, and subchondral bone changes were independent predictors of progression.
Conclusion: Among women recruited from the community, radiographic and clinical progression was greater in those with symptomatic RHOA, but still substantially less frequent than previously reported for hip OA patients in clinical settings. Asymptomatic RHOA and hips with an isolated finding of mild JSN (MJS of 1.5 mm to 2.5 mm) were unlikely to progress over 8 years.