Predictors of ASDAS-CRP inactive disease in axial spondyloarthritis during treatment with TNF-inhibitors: Data from the EuroSpA collaboration

OBJECTIVES: In patients with axial spondyloarthritis (axSpA) initiating their first tumor necrosis factor alpha-inhibitor (TNFi), we aimed to identify common baseline predictors of Ankylosing Spondylitis Disease Activity Score (ASDAS-CRP) inactive disease (primary objective) and clinically important improvement (CII) at 6 months, and drug retention at 12-months across 15 European registries. METHODS: Baseline demographic and clinical characteristics were collected. Outcomes were investigated per registry and in pooled data using logistic regression analyses on multiply imputed data. RESULTS: The consistency of baseline predictors in individual registries justified pooling the data. In the pooled dataset (n = 21,196), the 6-month rates for ASDAS inactive disease and ASDAS CII were 26% and 51%, and the 12-month drug retention rate 65% in patients with available data (n = 9,845, n = 6,948 and n = 21,196, respectively). Nine common baseline predictors of ASDAS inactive disease, ASDAS CII and 12-month drug retention were identified, and the odds ratios (95%-confidence interval) for ASDAS inactive disease were: age, per year: 0.97 (0.97-0.98), men vs. women: 1.88 (1.60-2.22), current vs. non-smoking: 0.76 (0.63-0.91), HLA-B27 positive vs. negative: 1.51 (1.20-1.91), TNF start year 2015-2018 vs. 2009-2014: 1.24 (1.06-1.45), CRP>10 vs. ≤10 mg/l: 1.49 (1.25-1.77), one unit increase in health assessment questionnaire (HAQ): 0.77 (0.58-1.03), one-millimeter (mm) increase in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) fatigue and spinal pain: 0.99 (0.99-1.00) and 0.99 (0.99-1.99), respectively CONCLUSION: Common baseline predictors of treatment response and adherence to TNFi could be identified across data from 15 European registries, indicating that they may be universal across different axSpA populations