DAPSA and ultrasound show different perspectives of psoriatic arthritis disease activity: results from a 12-month longitudinal observational study in patients starting treatment with biological disease-modifying antirheumatic drugs.

OBJECTIVES: Disease Activity index for PSoriatic Arthritis (DAPSA) (sum score 68/66 tender/swollen joint counts (68TJC/66SJC), patient's global assessment, pain and C-reactive protein (CRP)) is recommended for clinical assessment of disease activity in patients with psoriatic arthritis (PsA). Ultrasound (US) (grey scale (GS) and power Doppler (PD)) detects inflammation in joints and extra-articular structures. The present objectives were to explore the longitudinal relationships between DAPSA, clinical assessment as well as patient-reported outcome measures (PROMs) with US in patients with PsA initiating biological DMARDs and the associations between DAPSA and US remission. METHODS: 47 patients with PsA were examined at baseline and after 3, 6, 9 and 12 months. Assessments included 68TJC/66SJC, examiner's global assessment (EGA), PROMs, CRP, erythrocyte sedimentation rate (ESR) and US GS and PD (48 joints, 10 flexor tendons, 14 entheses, 4 bursae). Clinical composite scores and PD sum scores (0=remission) were calculated. Longitudinal associations were explored by generalised estimating equations with linear and logistic regression. RESULTS: DAPSA was not longitudinally associated to PD. 66SJC, ESR, 28-joint Disease Activity Score, EGA and CRP were longitudinally associated with PD (p<0.001-0.03), whereas the pain-related components of DAPSA (68TJC and pain) as well as PROMs were not associated. At 6-12 months, remission was achieved in 29%-33 % of the patients for DAPSA and 59%-70 % for PD. The association between DAPSA and PD remission was not significant (p=0.33). CONCLUSIONS: DAPSA was not associated with US inflammatory findings which indicates that DAPSA and US may assess different aspects of PsA activity.

Examination of intra and interrater reliability with a new ultrasonographic reference atlas for scoring of synovitis in patients with rheumatoid arthritis.

OBJECTIVE: Synovitis in patients with rheumatoid arthritis (RA) may be scored semiquantitatively (0-3) for B-mode (BM) and power Doppler (PD) ultrasonography. The objective was to assess the reliability of BM and PD examinations with a novel ultrasonographic atlas as reference. METHODS: Representative ultrasound images (including scores 0-3) of BM and PD from 24 different joints were collected to develop an ultrasonographic atlas. Ten RA patients were assessed twice by five rheumatologists performing BM and PD scoring (0-3) of 16 joints bilaterally (metacarpophalangeal 1-5, wrist (radiocarpal, intercarpal, radioulnar), elbow, knee, talocrural and metatarsophalangeal 1-5), with the novel ultrasonographic atlas as a reference. RESULTS: The median (range) percentages of exact agreements for BM/PD assessments were 73.1 (70.3-80.6)/83.7 (76.7-87.6) and for close agreement 98.1 (96.2-99.7)/98.0 (96.8-98.4) with weighted κ values of median (range) 0.77 (0.70-0.83) for BM and 0.83 (0.73-0.86) for PD. The intrarater intraclass correlation coefficients (ICC) for BM/PD scores were 0.95 (0.93-0.99)/0.97 (0.95-0.99) and interrater ICC were 0.95 (0.86-0.99)/0.97 (0.94-1.00). Scoring of 32 joints was completed in median 15 min (range 12-20). CONCLUSION: With the use of an ultrasonographic atlas as reference high intra and interrater reliability was found for BM and PD scoring. This novel atlas may be a useful resource in clinical practice and research.