Exploring difficult-to-manage axial spondyloarthritis: results from a Dutch clinical practice registry

To explore (1) the prevalence of difficult-to-manage axial spondyloarthritis (D2M axSpA) in clinical practice according to the Assessment of SpondyloArthritis international Society (ASAS) definition, (2) specific components of this definition contributing most to its fulfilment and (3) associated patient characteristics.

This cross-sectional study used data from the SpA-Net registry. Fulfilling the ASAS definition required: (1) treatment failure, (2) insufficient disease control (any of: [A] high disease activity (AxSpA Disease Activity Score [ASDAS] ≥2.1), [B] signs of active disease (e.g. peripheral manifestations) or [C] reduced health-related quality of life) and (3) a problematic management situation in the patient's or rheumatologist's perspective. Three variations of the ASAS definition were investigated, including only subcriterion A, B or C in domain 2. Treatment-refractory axSpA required fulfilment of the primary ASAS definition, an ASDAS ≥2.1 and CRP ≥5 mg/L. The prevalence of D2M axSpA per explored definition was calculated, and associated characteristics were assessed using logistic regression analyses.

Data from 263 patients were analysed. Overall, 9.7% had D2M axSpA (variations A-C: 3.6-8.7%) and 1.7% had treatment-refractory disease. 'Treatment failure' affected 9.9-11.6% of patients, 'insufficient disease control' affected 79.7% of patients (variation A: 57.0%, B: 44.6%, C: 51.4%) and 'problematic management' affected 51.4-60.2% of patients. Current smoking (OR = 3.1 [95% CI 1.1-8.7]) and a history of psoriasis (OR = 2.8 [95% CI 1.0-7.6]) were associated characteristics.

One in 10 patients with axSpA have D2M disease. Patient-reported outcomes contribute importantly to the classification of D2M axSpA. Current smoking and a history of psoriasis are associated characteristics.