Burden of Psoriatic Arthritis According to Different Definitions of Disease Activity: Comparing Minimal Disease Activity and the Disease Activity Index for Psoriatic Arthritis

OBJECTIVE: Treat‐to‐target strategies have improved outcomes in rheumatic diseases. In psoriatic arthritis (PsA), the proposed targets are the multidimensional target minimal disease activity (MDA) and the articular target Disease Activity index for PsA (DAPSA). The aim of this study was to compare the disease burden of PsA in patients with low disease activity according to the 2 definitions, MDA and DAPSA low disease activity (DAPSA‐LDA), 1 year after diagnosis. METHODS: We obtained data on MDA, DAPSA‐LDA and disease burden 1 year after diagnosis for patients included in the Dutch southwest early PsA cohort. Disease burden was assessed in 2 domains: “Body functions,” including the Short Form 36 bodily pain (SF‐36 BP) measure, and “Activity,” including the Health Assessment Questionnaire (HAQ). RESULTS: Among the 292 patients included, 48% achieved MDA and 74% achieved DAPSA‐LDA. Average scores for Body functions and Activity were better in patients who achieved MDA and those who achieved DAPSA‐LDA. The scores were significantly better in the 46% of patients who achieved both MDA and DAPSA‐LDA than in the 29% of patients who achieved only DAPSA‐LDA. The average SF‐36 BP score was higher in patients achieving both targets (73.8; 95% confidence interval [95% CI] 71.1‐76.5) than in patients achieving only DAPSA‐LDA (57.6; 95% CI 54.5‐60.8). Similarly, mean HAQ scores measuring Activity were 0.21 (95% CI 0.15‐0.26) and 0.63 (95% CI 0.53‐0.72), respectively. CONCLUSION: Among patients with newly diagnosed PsA, 48% achieved MDA and 74% achieved DAPSA‐LDA after 1 year of receiving usual care. The average disease burden was better in patients who achieved MDA and those who achieved DAPSA‐LDA. Also, patients who achieved only DAPSA‐LDA reported worse outcomes than those who also achieved MDA.