Background Psoriatic arthritis (PsA) belongs to the spondyloarthritides and disease activity can be evaluated by the Disease Activity Index for Psoriatic Arthritis (DAPSA) and the Composite Psoriatic Disease Activity Index (CPDAI) 1. The Ankylosing Spondylitis Disease Activity Score (ASDAS) is a composite disease activity score for ankylosing spondylitis covering peripheral involvement in both versions selected by ASAS international society (ASDASCRP and ASDASESR)2.
Objectives To evaluate the possible importance of ASDASCRP and ASDASESR to assess disease activity in PsA.
Methods In a cross-sectional study patients attending our outpatient clinic and fulfilling CASPAR criteria of PsA underwent a complete rheumatologic assessment to calculate the disease activity score CPDAI and DAPSA for PsA as well as the ASDASCRP and ASDASESR after informed consent was obtained. On the same day a rheumatologist unaware of the clinical status of the patients performed B-mode and power Doppler (PD) sonography of peripheral joints, of tendon sheets and entheses according to the MASEI, and of perisynovial tissue of finger joints. Results were graded semi-quantitatively and sum scores were calculated for PD signals and for pathological B-mode and PD findings together (GLUS, range 0–832). Descriptive statistics were used to summarise the data and correlations were analysed by the Spearman's rank correlation test.
Results 67 of 84 included patients (49 male, 18 female; mean age 51 (SD 12) years; median disease duration 7 years (IQR 4–18) could be evaluated. We found a strong correlation of the DAPSA and CPDAI score and a low but significant correlation of the GLUS and the PD sum score with the ASDASESR and ASDASCRP (table). We observed only a moderate association of the DAPSA with the GLUS (r=0.52, 95%CI 0.32–0.68) and the association of the CPDAI with the GLUS and the PD sum score (r=0.25, 95%CI 0.003–0.47 and r=0.19, 95%CI -0.06–0.42, respectively) was even lower than the correlation of the GLUS and the PD sum score with the ASDASESR and the ASDASCRP. In PsA-patients with clinically defined remission 25.0% of the patients fulfilled the CPDAI and 29.1% the DAPSA remission criteria. However, in patients with clinically defined remission 50.0% and 54.2% fulfilled the ASDASESR and ASDASCRP criteria for inactive disease.
Conclusions This cross-sectional study shows that the ASDAS might also be a valuable tool to measure disease activity and to define clinical remission in PsA.
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Lukas C, Landewe R, Sieper J, Dougados M, Davis J, Braun J, et al. Development of an ASAS-endorsed disease activity score (ASDAS) in patients with ankylosing spondylitis. Ann Rheum Dis 2009;68:18–24.
Disclosure of Interest None declared