Attainment of Minimal Disease Activity Using Methotrexate in Psoriatic Arthritis

An international task force has recommended that disease remission or minimal disease activity (MDA) be the target of treatment for psoriatic arthritis (PsA) and that remission or MDA should be attained within 6 months of initiating medication. The aim of this study was to establish the proportion of patients with PsA who achieve MDA after 6 months of methotrexate (MTX) treatment.

Patients who initiated MTX and were naive to biologics between 2004 and 2014 were included. The primary outcome was the achievement of MDA after 6 months of MTX, defined as the presence of at least 5 out of the following 7: tender joint count ≤ 1, swollen joint count (SJC) ≤ 1, Psoriasis Area Severity Index (PASI) ≤ 1 or body surface area ≤ 3%, tender entheseal points ≤ 1, Health Assessment Questionnaire score ≤ 0.5, patient global disease activity visual analog scale (VAS) score ≤ 20, and patient pain VAS ≤ 15. Of 204 patients identified, 167 were treated with MTX for at least 3 months and had sufficient data for analysis at 6 months.

At 6 months, 29 patients (17.4%) achieved MDA; 97 patients (58.1%) achieved an SJC ≤ 1 and 138 (82.6%) a PASI ≤ 1. Only 22 (13.2%) achieved the patient global disease activity criterion. Lower back pain and dactylitis were associated with a lower probability of achieving MDA.

MTX use achieves MDA by 6 months in < 20% of patients. This compares unfavorably with data for tumor necrosis factor inhibitor use.