Are MDA criteria created equal in PsA? Save

Minimal Disease Activity, MDA, criteria are used to evaluate PsA disease activity and response to treatment. For reference, MDA is defined as meeting ≥5 criteria: tender joint count ≤1, swollen joint count ≤1, patient global visual analogue scale (PG VAS) ≤20mm, pain VAS ≤15mm, health assessment questionnaire (HAQ) ≤0.5, enthesitis count ≤1 and psoriasis body surface area ≤3%.

Given that a patient only has to meet 5 of the 7 criteria, should the individual components be weighted equally? 

Over 450 PsA patients from ReFlap, a cross-sectional international study of adult patients with PsA for >2 years, were analyzed by Dr. Yazji et al in Abstract 1496. Patients self-reported remission (REM) or low disease activity (LDA) by answering positively to the questions ‘At this time, is your psoriatic arthritis in remission, if that means you feel your disease is as good as gone?’ and ‘At this time, are you in low disease activity, if this means your disease is in low activity but it’s not as good as gone?’ respectively.

Nearly 40% of patients reported MDA with an additional 25% meeting MDA but not VLDA. The most common MDA criteria not met were PG VAS and Pain VAS. Additional analyses showed that MDA specificity was consistently high for the score overall and that regardless which criteria were “missing,” the clinical tool does not over-detect patients to be in MDA.  They concluded that the likelihood of a patient self-reporting LDA/REM and the specificity of the MDA score was unrelated to which criteria for MDA were met. 

This supports continued use of MDA in clinical practice and remains a treat to target approach appealing to both PsA patients and rheumatologists.