Comparison of Composite Indices Tailored for Psoriatic Arthritis Treated with csDMARD and bDMARD: A Cross-sectional Analysis of a Longitudinal Cohort

Objective. In a complex disease such as psoriatic arthritis (PsA), several methods are available to define remission or low disease activity (LDA), including the assessment of different clinical features. The aim of this study was to compare the composite indices tailored for PsA in patients treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARD) and biological DMARD (bDMARD). Methods. Patients with PsA classified with the ClASsification criteria for Psoriatic ARthritis criteria and with > 6 months followup treated with first csDMARD and bDMARD were consecutively enrolled. To assess disease activity, composite indices tailored for PsA were used, such as the Disease Activity Index for Psoriatic Arthritis (DAPSA), clinical DAPSA (cDAPSA), Psoriatic Arthritis Disease Activity Score (PASDAS), minimal disease activity (MDA) 5/7, and MDA 7/7. DAPSA and cDAPSA score <= 4, MDA 7/7, and PASDAS <= 1.9 identified remission. MDA 5/7, DAPSA score <= 14, cDAPSA score <= 13, and PASDAS <= 3.2 identified the MDA and LDA criteria. Results. One hundred nine patients with PsA were enrolled: 79 patients were receiving stable treatment with bDMARD and 30 with csDMARD. Overall, 28 (25.6%), 23 (21.1%), 19 (17.4%), and 13 patients (11.9%) were in cDAPSA remission, DAPSA remission, MDA 7/7, and PASDAS <= 1.9, respectively. Moreover, 54 (49.5%), 80 (73.3%), 79 (72.3%), and 38 patients (34.8%) were in MDA 5/7, DAPSA LDA, cDAPSA LDA, and PASDAS LDA. Patients treated with bDMARD had significantly lower median DAPSA, cDAPSA, and PASDAS score than patients treated with csDMARD. Conclusion. Patients with PsA receiving bDMARD are more likely to achieve a status of MDA and remission when compared with csDMARD. PASDAS <= 1.9 and MDA 7/7 seem to be stringent remission criteria.