Doppler enthesitis: a potential useful outcome in the assessment of axial spondyloarthritis and psoriatic arthritis.

OBJECTIVE

To analyse the frequency of power Doppler (PD) enthesitis in active axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) patients and its potential usefulness in clinical practice.

METHODS

A prospective multicentre cross-sectional study in patients with axSpA and PsA with active disease was undertaken. Patients underwent bilateral ultrasound (US) examination of the peripheral entheses according to the Madrid Sonographic Enthesis Index (MASEI). The MASEI and Outcome Measures in Rheumatology (OMERACT) PD enthesitis definitions were checked. An inter-reader analysis of recorded videos was performed to determine reliability.

RESULTS

Sixty-four consecutive patients were included. The mean DAS28 (3.9 ± 1.3) for peripheral involvement, mean BASDAI (5.6 ± 2.2) for axial involvement, and CRP values (10 ± 10.9) reflected moderate-high disease activity at baseline. The mean global MASEI score was 29.4 (± 11.4), and 55 patients (86%) scored ≥ 18 (proposed cut-off point to diagnose SpA). At the patient level, abnormal US findings consistent with at least one enthesis showing a PD signal were observed in 52 (81.3%) patients using the MASEI PD definition and 48 (75%) using the OMERACT PD definition, without significant variation between axSpA and PsA. The inter-reader reliability was excellent (kappa = 0.92 for MASEI PD and 0.86 for OMERACT PD).

CONCLUSIONS

PD enthesitis was found in the majority of patients with active axSpA and PsA, independent of axial or peripheral affectation. Both MASEI and OMERACT PD definitions were useful in detecting active enthesitis. These findings support the usefulness of a PD US evaluation of entheses in the assessment of axSpA and PsA. Key Points • PD enthesitis is a very common finding in patients with active axSpA and PsA • Both MASEI and OMERACT PD definitions are useful to detect active enthesitis • US enthesitis may reveal information in axSpA and PsA.