Background Minimal disease activity (MDA)  was proposed by EULAR as an alternative target of treatment of psoriatic arthritis (PsA) pats. in the absence of remission . MDA comprises 7 items (TJC≤1; SJC≤1; pat. global assessment VAS score ≤ 2cm; pat.pain VAS score ≤1,5cm; HAQ≤0,5; tender enthesial points≤1; psoriasis BSA ≤3%). This target has also been incorporated in the recommendations of Czech Rheumatologic Association. At the same time we use Disease Activity Index for Psoriatic Arthritis (DAPsA)  for the assessment of the disease activity.
Objectives We put the question of how MDA correlates with this index (DAPsA).
Methods 103 consecutive patients with PsA treated according to standard algorythm were followed for two to four years (up to 5 controls) and their clinical activity was assessed using “disease activity index in PsA“(DAPsA) in four modifications . We retrospectively assessed at each visit if the pats. reached MDA using 7 items (yes=1/no=0) and the number of items of MDA they fulfilled (0-7). In total 489 assessment was performed. Enthesitis (13 sites) was defined merely as a tenderness on palpation, which is a bit equivocal. Also a quantitative assessment of psoriasis (BSA) by rheumatologist is not too accurate. So we assessed the achievement of MDA using only 5 items (with omitting of enthesitis and BSA) in the same patients.
Results (1) The Pearson correlation coefficient showed to be pretty high between the increasing number of items of MDA fulfilled and all 4 modifications of DAPsA (0,961-0,975), as well as the p-value p=(0,01)- tab.1. (2) When using 5-item MDA, the correlation coefficient remained high, and the p-value even increased (p=0,005).
Conclusions MDA as a therapeutic target of pats.with psoriatic arthritis closely follows disease activity as assessed by composite measure DAPsA in all its modifications. Even omitting of enthesitidies and BSA (5-item MDA) maintains its ability to reflect disease activity. Both modifications of MDA are suitable as a therapeutic target for the treatment of patients with PsA.
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Acknowledgements Supported by the Research program of the Ministry of health of Czech Republic: IGA MZ CR: No. 000 000 23728
Disclosure of Interest None Declared