POS0114 Exploring difficult-to-manage axial spondyloarthritis: Results from a dutch clinical practice registry

Background: Patients with axial spondyloarthritis (axSpA) who experience multiple challenges in their disease management may be considered to have ‘difficult-to-manage' (D2M) disease [1]. A consensus definition for this phenomenon has been established by the Assessment of SpondyloArthritis international Society (ASAS), however, limited evidence is currently available on the prevalence of D2M axSpA according to this definition and associated patient characteristics [2].
Objectives: To explore (1) the prevalence of D2M axSpA, according to the ASAS definition, in a multicentre clinical practice SpA registry, (2) which components of the ASAS definition most frequently contribute to being classified as having D2M axSpA, and (3) which patient characteristics are associated with having D2M axSpA.
Methods: This cross-sectional study used data from the Dutch web-based monitoring system SpA-Net. D2M axSpA according to the ASAS definition required fulfillment of all three of the following domains: (1) treatment failure (failure of ≥2 biological or targeted synthetic disease-modifying anti-rheumatic drugs [b/tsDMARDs] with different modes of action), (2) insufficient control of signs and symptoms (any of: [A] high disease activity (Axial Spondyloarthritis Disease Activity Score [ASDAS] ≥2.1), [B] signs suggestive of active disease (defined in our study as an elevated C-reactive protein [CRP], active peripheral manifestations [arthritis, enthesitis or dactylitis], and/or active psoriasis), or [C] reduced health-related quality of life [HRQoL]), and (3) a problematic management situation in the patient's or rheumatologist's perspective (defined in our study as a patient and/or physician global assessment score of the disease state ≥5/10). Three variations of the ASAS definition were investigated, including only subcriterion A, B or C in domain 2. Treatment-refractory axSpA, a subset of the D2M axSpA concept, required fulfilment of the primary ASAS definition with both an ASDAS ≥2.1 and CRP ≥5mg/L. The prevalence of D2M axSpA per explored definition was calculated, and characteristics associated with fulfilling the primary ASAS definition were assessed using logistic regression analyses, adjusted for age and sex. The analysis of each definition included patients with available data on any of the instruments considered in each domain.
Results: Data from 269 patients were analysed, of which 125 (46.5%) were female, the mean age was 51.7 (SD 14.1) years, the mean symptom duration was 21.3 (SD 12.3) years, the mean ASDAS was 2.4 (SD 1.0), and 136 (50.6%) had a history of using at least one b/tsDMARD. Overall, 9.5% (n=23/242) had D2M axSpA according to the primary ASAS definition and 1.7% (n=4/242) had treatment-refractory disease (Figure 1). In the three variations explored, the lowest prevalence was observed in the variation based purely on objective signs of active disease (variation B: 3.5% [n=8/227]), compared to the variations based on the ASDAS (variation A: 8.6% [n=23/269]) and HRQoL (variation C: 7.5% [n=14/186]). When considering the three domains individually, ‘treatment failure' affected 9.7-11.3% of patients, ‘insufficient control of signs and symptoms' affected 80.2% of patients (variation A: 57.6%, variation B: 45.8%, variation C: 52.2%), and ‘problematic management' affected 52.7-60.7% of patients. Current smoking (OR: 3.1 [95%CI 1.1-8.9]) and having a history of psoriasis (OR: 2.8 [95%CI 1.0-7.8]) were characteristics associated with D2M axSpA (Table 1).
Conclusion: One in ten patients with axSpA have D2M disease. Patient-reported outcomes contribute importantly to the classification of D2M axSpA, whereas treatment failure is the most prominent limiting factor to fulfil the ASAS definition. Current smoking and a history of psoriasis are associated characteristics. Further research is necessary to optimise management strategies for affected patients.