Ultrasound Doppler enthesitis shows sensitivity to change after biological therapy in spondyloarthritis and psoriatic arthritis patients.

OBJECTIVE

To explore the sensitivity to change in power Doppler (PD) enthesitis in active spondyloarthritis (SpA) and psoriatic arthritis (PsA) patients.

METHOD

This was a longitudinal study in patients with SpA and PsA with active disease [patients starting or switching to biological disease-modifying anti-rheumatic drugs (bDMARDs)]. The MAdrid Sonographic Enthesitis Index (MASEI) was performed at baseline and at 3 and 6 month visits. The MASEI and Outcome Measures in Rheumatology (OMERACT) PD enthesitis definitions were checked. Reliability analysis among three readers was performed with ultrasound (US)-recorded videos.

RESULTS

US examinations of 25 patients were included; 16 (64%) had SpA and nine (36%) PsA. The median (interquartile range, IQR) age was 49 (41-61) years, and 13 patients (52%) were female. The median (IQR) 28-joint Disease Activity Score of 3.6 (2.3-4.2), Bath Ankylosing Spondylitis Disease Activity Index of 6.7 (6.1-7.4), and C-reactive protein value of 8.2 (1.6-20) reflected moderate to high disease activity at baseline. Both MASEI and OMERACT PD enthesitis improved significantly at 3 and 6 month follow-up (p < 0.05) and showed sensitivity to change (standard error of measurement = 0.47 and 0.61, respectively). Improvement in clinical activity outcomes was significantly associated with decreases in MASEI and OMERACT PD enthesitis counts (p < 0.05). The MASEI and OMERACT PD definitions had excellent reliability (kappa = 0.918 and 0.865, respectively).

CONCLUSION

PD enthesitis significantly improved at 3 and 6 month follow-up in patients undergoing bDMARD therapy. Both MASEI and OMERACT PD US enthesitis reflect response to treatment.