Ultrasonographic evaluation in psoriatic arthritis is of major importance in evaluating disease activity.

Objective: To investigate the association between clinical and ultrasonographic (US) evidence of inflammation in psoriatic arthritis (PsA), as well as to compare clinical and US remission criteria.

Methods: In this cross-sectional study 141 PsA outpatients were included. Minimal disease activity (MDA), 28-joint Disease Activity Score (DAS28), Disease Activity Index for PSoriatic Arthritis (DAPSA) and modified versions of Composite Psoriatic Disease Activity Index (CPDAI) and Psoriatic ArthritiS Disease Activity Score (PASDAS) were assessed. Remission criteria were explored. US evaluation was performed on 34 joints, in addition to joints being tender/swollen by 66/68 joint count, 30 tendons, 10 entheses and additionally entheses found to be tender by clinical examination of 19 other entheses. Power Doppler (PD) and grey scale global scores on joints, entheses and tendons were assessed. US remission was defined as no PD activity in joints, entheses and tendons.

Results: DAPSA and DAS28, but not CPDAI and PASDAS, were associated with PD activity. MDA was fulfilled in 22.7% and the clinical remission criteria in 5.7%-9.9% of the patients. US remission was found in 49.6% of the patients. The prevalence of PD activity at joints, entheses and tendons was similar for patients fulfilling versus not fulfilling MDA/clinical remission criteria. MDA (OR 2.3, p=0.048), DAPSA ≤3.3 (OR 4.2, p=0.025) and Boolean's (OR=7.8, p=0.033) definitions of remission were found to predict US remission.

Conclusions: We found major discrepancies between US and clinical findings. DAPSA and DAS28 reflected US findings better than CPDAI and PASDAS. MDA, DAPSA and Boolean's remission criteria predicted US remission.