Patients with ankylosing spondylitis (AS) showed a high prevalence of hip involvement at a rate of 10% to 23%, depending on the method of assessment, according to a study published in Rheumatology. Data also show that 6 months of tumor necrosis factor-α (TNF-α)  inhibitor therapy resulted in a significant decrease in tender hip joints, inflammatory ultrasound lesions, and positive power Doppler signals.  

This daily clinical practice observational cohort study was performed to assess the prevalence of ultrasound, radiographic, and clinical hip involvement in patients with active AS, to identify associations between the assessments, and to evaluate the effect of 6 months of TNF-α inhibitor therapy. Participants beginning TNF-α inhibitor therapy were first assessed for hip joint involvement, a baseline radiographic evaluation was performed using the Bath Ankylosing Spondylitis Radiology Index of the hip, and participant-reported history of hip involvement was taken. Ultrasound and clinical examinations of hip joints were performed at baseline and after 6 months of treatment.

Of 111 participants, 20% reported a history of hip involvement and 23% had tender hip joints at baseline. A moderate correlation was found between history of hip involvement and radiographic hip involvement (phi coefficient, 0.333; <.05). A weak correlation was found between structural ultrasound lesions and tender hip joints (phi coefficient, 0.193; <.05) and radiological hip involvement (phi coefficient 0.203; <.05). No significant correlation was found with any other assessment, and only 2 patients with inflammatory ultrasound lesions also reported a painful hip. After participants received 6 months of TNF-α inhibitor therapy, the total number of inflammatory ultrasound lesions decreased from 29 to 9, positive power Doppler decreased from 22 to 6, and tender hip joints decreased from 29 to 11. The percentage of total participants with tender hip joints significantly decreased from 25% to 12% (<.05).

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Study investigators conclude, “based on our results, [ultrasound] examination of hip joints is a useful, sensitive and objective method that contributes to the assessment of hip involvement in AS in daily clinical practice, including the evaluation of the response of TNF-α blocking therapy on inflammatory lesions.”

Disclosures: Study investigators report receiving consulting fees or research support from Abbvie, Pfizer, MSD, Novartis, and Union Chimique Belge.

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Reference

Wink F, Arends S, Maas F, et al. High prevalence of hip involvement and decrease in inflammatory ultrasound lesions during tumour necrosis factor-α blocking therapy in ankylosing spondylitis [published online January 8, 2019]. Rheumatology (Oxford). doi:10.1093/rheumatology/key382