Minimal disease activity and associated factors in patients with psoriatic arthritis: cross-sectional study from a single center.

Introduction: Psoriatic arthritis (PsA) is a heterogeneous disease with various manifestations such as dactylitis, enthesitis, spondylitis, and skin involvement. Minimal disease activity (MDA) has been successfully used in daily clinical practice and is considered a reasonable treatment target in patients with PsA. In this study, we aimed to evaluate the MDA status and associated factors in patients with PsA in our tertiary referral clinic. Material and methods: This cross-sectional study included patients who met the CASPAR classification criteria and had at least 6 months of follow-up data between 2001 and 2021. Patients who met at least 5 of 7 criteria (tender joint count ≤ 1/68, swollen joint count ≤ 1/66, Psoriasis Area Severity Index [PASI] ≤ 1, Visual Analogue Scale [VAS] ≤ 15, patient global VAS ≤ 20, Health Assessment Questionnaire-Disability Index [HAQ-DI] ≤ 0.5, and enthesitis number ≤ 1) were considered to achieve MDA. Results: Data from 172 patients (61% female) were analyzed and included in the study. While most patients had polyarticular involvement (33.7%), mono-oligoarthritis was present in 30.2%, mixed type in 26.2%, isolated distal interphalangeal arthritis in 5.8%, isolated spondylitis in 2.9%, and arthritis mutilans in 1.2%. Overall, 95 (55.2%) of the patients were observed at MDA, which was lower in tumor necrosis factor inhibitor (TNFi) users compared to only conventional synthetic disease-modifying antirheumatic drug users. In univariate analysis, MDA was associated with higher patient age, longer psoriasis duration, late-onset PsA, and continued use of first TNFi. In multivariate analysis, higher patient age, late-onset PsA, and higher continuation rate of first TNFi were associated with MDA. Conclusions: In the study, more than half of our patients achieved MDA status. A higher MDA rate was associated with a higher continuation rate at first-line TNFi treatment. The relatively large population who could not reach MDA status in our study indicates an unmet need for monitoring and treatment of PsA.