HIP INVOLVEMENT IN SPONDYLOARTHRITIS: PREVALENCE AND CHARACTERISTICS FROM A SINGLE RHEUMATOLOGY OUTPATIENTS CENTRE

Hip involvement is a well-recognized feature of axial spondyloarthritis (AS). This study aimed to assess the prevalence of hip involvement and its relationship with both symptomatic and structural severity in a cohort of AS patients treated in an outpatient rheumatology clinic.Methods: A retrospective, single-center study (2019–2023) included confirmed AS patients. Hip involvement was defined as hip pain related to AS-driven inflammation, confirmed by radiographic imaging (BASRI-hip score of ≥2). Demographic data and parameters of both symptomatic and structural severity were collected. The risk of hip involvement based on disease duration was evaluated using Kaplan-Meier analysis.

Results: Among 137 AS patients, 89 (64.9%) were men and 48 (35.0) were women. The mean age was 42.2 years ± 14 (range: 18–76), and the mean disease duration was 7.5 years ± 9.1 (range: 0.5–38). Radiographic evidence of hip involvement was present in 19 patients (13.9%): unilateral in 9 patients (6.6%), and bilateral in 10 patients (7.3%). Hip involvement was more common in men, those with longer disease duration, and those with a higher incidence of uveitis. Patients with hip involvement exhibited higher symptomatic (BASDAI and ASDAS) and structural (mSASS) severity scores. By disease duration, 18.6% of male patients had hip involvement after 10 years, rising to 48.8% after 20 years.

Conclusion: Hip involvement is a frequent manifestation of AS, often presenting bilaterally and associated with longer disease duration and greater disease severity. However, its prevalence appears lower in outpatient settings compared to university hospital series.