FACTORS ASSOCIATED WITH RADIOGRAPHIC HIP INVOLVEMENT IN ANKYLOSING SPONDYLITIS

BackgroundHip involvement is a classic feature of ankylosing spondylitis (AS). It causes functional impairement and disability in patients with AS. Although, many studies have looked at factors associated with radiographic hip involvement, these remain debated.ObjectivesTo define the factors associated with radiographic hip involvement in patients with AS.MethodsA cross-sectional comparative study of 105 patients was performed. Hip involvement was defined as hip pain considered related to AS inflammation and confirmed radiographically. The patients were classified into two categories: (1) no hip involvement, (2) hip involvement according to a Bath Ankylosing Spondylitis Radiology Index (BASRI)-hip score ≥2. Multivariate logistic regression analyses were used to identify the factors associated with radiographic hip involvement.ResultsFifty-three patients had radiological hip involvement and 52 patients were whithout hip involvement. Multivariate logistic regression analyses showed male sex (OR 6.383 IC 1.553-26.29, p=0.010), Bath Ankylosing Spondylitis Functional Index (BASFI) score (OR 1.436, IC 1.079-1.913, p=0.013), and BASRI-spine score (OR 1.456, IC 1.190-1.783, p<0.001) to be significantly associated with radiographic hip involvement, and an inverse relation-ship with age at onset (OR 0.955, IC 0.995-0.998, p=0.038) was seen.ConclusionMale sex, younger age at onset, worse BASFI score and worse BASRI-spine score are associated with radiographic hip involvement. AS patients with risk factors for radiographic hip involvement should be diagnosed at an early stage to improve their quality of life.References[1]Zhao J, Zheng W, Zhang C, Li J, Liu D, Xu W. Radiographic hip involvement in ankylosing spondylitis: factors associated with severe hip diseases. J Rheumatol. 2015 Jan;42(1):106-10.[2]Burki V, Gossec L, Payet J, Durnez A, Elhai M, Fabreguet I, Koumakis E, Meyer M, Paternotte S, Roure F, Dougados M. Prevalence and characteristics of hip involvement in spondyloarthritis: a single-centre observational study of 275 patients. Clin Exp Rheumatol. 2012 Jul-Aug;30(4):481-6. Epub 2012 Aug 29.[3]Chen HA, Chen CH, Liao HT, Lin YJ, Chen PC, Chen WS, et al. Factors associated with radiographic spinal involvement and hip involvement in ankylosing spondylitis. Semin Arthritis Rheum 2011;40:552-8.Disclosure of InterestsNone declared