Background/Purpose:  Although remission remains the ultimate treatment goal in psoriatic arthritis (PsA) management, minimal disease activity (MDA), which encompasses remission and low disease activity, constitutes an attainable goal. Given that variability may exist across Canadian provinces both in regard to patient characteristics at anti-TNF initiation and in PsA management in routine clinical practice, the aim of the current analysis was to assess the regional variability in MDA achievement among Canadian patients initiating treatment with anti-TNF in real-world.

Methods:  BioTRAC is an ongoing, prospective registry of patients initiating treatment for PsA, ankylosing spondylitis, or rheumatoid arthritis with infliximab or golimumab. PsA patients who were enrolled during 2002-2015, had ≥1 follow-up assessment and MDA data available were included. 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) ≤20 mm, HAQ≤0.5, tender entheseal points ≤1. Provinces were regrouped by region: Western (Alberta, British Columbia, and Saskatchewan), Ontario, Quebec and Maritimes. Continuous and categorical variables were assessed with the non-parametric Kruskal-Wallis test and the Chi-square test, respectively.

Results:  223 PsA patients (51.4% male) were included in the analysis. The mean (SD) age was 49.8 (11.1) years, and disease duration was 5.8 (6.6) years. The proportion of patients in BioTRAC by Canadian region was 6.4%, 50.5%, 29.7% and 13.4% for the Western region, Ontario, Quebec and the Maritime region, respectively. The mean (SD) disease duration was significantly different among regions with [Western: 5.00 (5.48), Ontario: 5.76 (6.51), Quebec: 7.47 (7.60), Maritimes: 1.8 (1.9) years; p=0.027]. Baseline disease parameters for TJC, SJC, pain, PtGA, and HAQ-DI were statistically comparable at baseline among Canadian regions. However, significant between-group differences were observed at baseline for mean (SD) enthesitis count [Western: 7.00 (4.21), Ontario: 1.14 (2.90), Quebec: 1.33 (2.14), Maritime: 3.16 (3.88); p<0.001], and PASI [Western: 4.76 (4.98), Ontario: 3.71 (5.51), Quebec: 1.45 (2.94), Maritime: 1.18 (1.32); p=0.001]. At baseline, 6 and 12 months of treatment, 11.7%, 43.5%, and 44.8% of patients achieved MDA, respectively. A statistical trend was observed between regions with respect to MDA achievement at 6 or 12 months of treatment (p=0.127). Ontario and Quebec patients had the highest MDA rates (55.9% and 52.1%), while 44.4% and 18.2% of patients in Maritime and Western provinces presented with MDA, respectively.

Conclusion:  MDA achievement rates vary across Canada which could be attributed to differences in the patient profile and in disease duration at anti-TNF initiation.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/regional-variability-of-minimal-disease-activity-among-psoriatic-arthritis-patients-in-canada-an-analysis-from-a-prospective-observational-registry/