Background Psoriatic arthritis (PsA) is a systemic inflammatory disease with articular and extra-articular features, the disease activity ranges from mild mono-oligoarthritis to destructive polyarthritis. Hence, establishing the prognosis of a patient with PsA is important to better define the treatment strategy. Furthermore, minimal disease activity (MDA) is a validated composite outcome measure since it correlates well with long-term outcomes (e.g. development of joint damage)1.
Objectives The aim of this study was to identify the baseline clinical variables associated with MDA at 12th month of follow up in two cohorts of early PsA.
Methods Consecutive PsA patients, attending the outpatient Early Arthritis Clinic in Udine or Verona in the last two years, were assessed. All the included patients had: I) CASPAR score ≥22 II) new diagnosis of PsA III) a complete clinical data and follow-up of at least 12 months. The GRAPPA recommendations on the management of PsA were followed. Statistical analysis included T- test, ANOVA and Pearson's test in order to find possible predictors of MDA.
Results Eighty-one early PsA patients were included in the study. 47/81 (58.2%) reached MDA at 12th month of follow-up; 68/81 (83.9%) were in c-DMARDs while 11/81 (13.6%) were in b-DMARDs. Two variables at baseline were selected comparing the groups based on achievement of MDA. These were: 1) LEI, which was significantly lower at baseline in patients reaching MDA (0.43 Vs 0.86, p=0.001); and 2) a lower baseline CRP (1.2 mg/dl vs 2.8 mg/dl, p=0.008). Of note, neither the baseline disease activity evaluated with DAPSA nor the time to referral were selected by statistical analysis.
Conclusions Baseline lower LEI score and lower CRP were identified as clinical predictors of MDA after 12 months of treatment in PsA. Therefore, patients with a more active enthesitis or higher inflammation may have a less responsive disease. This may be relevant to select proper treatments at baseline, and indirectly confirms that enthesitis is a key therapeutic target in PsA.
Coates LC, Fransen J, Helliwell PS. Defining minimal disease activity in psoriatic arthritis: a proposed objective target for treatment. Ann Rheum Dis 2010; 69: 48–53.
Coates LC, Conaghan PG, Emery P et al. Sensitivity and specificity of the classification of psoriatic arthritis criteria in early psoriatic arthritis. Arthritis Rheum 2012; 64: 3150–3155.
Disclosure of Interest None declared