IN outpatient axial spondyloarthritis care, radiographic hip involvement affected 13.90% and aligned with greater severity overall.
Hip Involvement in Axial Spondyloarthritis
Hip involvement is a recognized extraspinal manifestation of axial spondyloarthritis and can be associated with poorer functional outcomes. In this retrospective, single center analysis from a rheumatology outpatient clinic in Rabat, Morocco, researchers evaluated confirmed ankylosing spondylitis patients followed between 2019 and 2023 to better define how often hip disease appears in routine outpatient care and how it relates to symptomatic and structural severity.
Hip involvement was defined as hip pain attributed to inflammatory disease activity and supported by radiographic findings, using a Bath Ankylosing Spondylitis Radiology Hip Index (BASRI) score of at least 2. Among 137 patients, radiographic hip involvement was identified in 19 patients. Involvement was unilateral in nine patients and bilateral in 10, reinforcing that hip involvement may present on one side or affect both hips.
Who Was Most Likely to Have Hip Involvement
Hip involvement was more common in men and in patients with longer disease duration. The analysis also found a higher incidence of uveitis among those with hip involvement, suggesting clustering of more severe clinical features in this subgroup. Using Kaplan Meier estimates, the risk of hip involvement rose over time, with 18.6% of male patients affected after 10 years of disease duration and 48.8% after 20 years.
Association With Higher Disease Activity and Damage
Patients with hip involvement had higher symptomatic severity scores, including Bath Ankylosing Spondylitis Disease Activity Index and Ankylosing Spondylitis Disease Activity Score, alongside greater structural burden as reflected by higher modified Stoke Ankylosing Spondylitis Spine Score values. The authors concluded that hip involvement is a frequent manifestation linked to longer disease duration and greater disease severity, while noting that prevalence in this outpatient cohort was lower than figures commonly reported from university hospital series.
Reference: El Maghraoui A. Assessment of the Prevalence and Characteristics of Hip Involvement in Spondyloarthritis: Results From a Rheumatology Outpatient Center. Cureus. 2026;18(1):e101822. doi:10.7759/cureus.101822.
