Background/Purpose : Early achievement of minimal disease activity (MDA) is recommended as a valid treat-to-target approach in psoriatic arthritis (PsA). The purpose of the current analysis was to evaluate disease progression in PsA patients among non-achievers of MDA treated with anti-TNF agents under Canadian routine practice.  

Methods : Biologic Treatment Registry Across Canada (BioTRAC) is an ongoing, prospective registry of patients initiating treatment for rheumatoid arthritis, ankylosing spondylitis, or PsA with Infliximab (IFX) or Golimumab (GLM), or with ustekinumab (UST) for PsA. Eligible people for this analysis included PsA patients treated with IFX who were enrolled since 2005 or with GLM enrolled since 2010 or with UST enrolled since 2014 and with available MDA information at 6 and 12 months of treatment. MDA was defined as the fulfillment of ≥5 of the following criteria: TJC28≤1, SJC28≤1, PASI≤1 or BSA≤3, Pain (VAS)≤15mm, PtGA (VAS)≤20mm, HAQ ≤0.5, tender entheseal points ≤1. Pairwise comparisons in disease parameters were assessed with the non-parametric Wilcoxon test. Variables associated with improved DAS28 and MDA achievement were examined using general linear models and logistic regression, respectively, wherein variables showing a statistical trend (P<0.150) in univariate analysis were considered in multivariate analysis to identify predictors.

Results: A total of 106 patients (55.2% male and 88.7% bio-naïve) were included with a mean (SD) age and disease duration of 49.6 (11.4) and 5.6 (6.9) years, respectively. The proportion of patients who achieved MDA at 6 months was 49.1% (n=52) while 50.9% (n=54) did not achieve MDA. Among patients with MDA at 6 months, 75.0% had sustained MDA at 12 months and among the non-achievers, 14.8% achieved MDA at 12 months of treatment. Disease parameters over time among the non-MDA achievers at 6 months are described in Table 1; overall, no statistical changes were observed between 6 months and 12 months. Multivariate logistic regression analysis showed that lower baseline HAQ (OR=0.459, P=0.071) and MDA achievement at 6 months were associated with higher odds (OR=12.604; P<0.001) of MDA achievement at 12 months of treatment. Multivariate general linear models showed that MDA achievement at 6 months (B=-0.770, P=0.042) and being bio-naïve (B=-2.296, P=0.001) were significant predictors of DAS28 improvement at 12 months of treatment.

Conclusion: The results of the current analysis have shown that achievement of MDA at 6 months is critical for MDA achievement/maintenance at 12 months highlighting the importance of intensive treatment early on. Furthermore, these results highlight the importance of treatment optimization in cases where MDA is not achieved.     Table 1: Disease Parameters for MDA Non-Achievers at 6 Months of Treatment