LAUSR

OBJECTIVES Many axial spondylarthritis (axSpA) patients receive a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) in combination with a tumour necrosis factor inhibitor (TNFi). However, the value of this co-therapy remains unclear. The objectives were to describe the characteristics of axSpA patients initiating a first TNFi as monotherapy compared with co-therapy with csDMARD, to compare one-year TNFi retention and remission rates, and to explore the impact of peripheral arthritis. METHODS Data was collected from 13 European registries. One-year outcomes included TNFi retention and hazard ratios (HR) for discontinuation with 95% confidence intervals (95%CI). Logistic regression was performed with adjusted odds ratios (OR) of achieving remission (ASDAS-CRP < 1.3 and/or BASDAI < 2) and stratified by treatment. Inter-registry heterogeneity was assessed using random-effect meta-analyses, combined results were presented when heterogeneity was not significant. Peripheral arthritis was defined as ≥ 1 swollen joint at baseline (=TNFi start). RESULTS Amongst 24 171 axSpA patients, 32% received csDMARD co-therapy (range across countries: 13.5% to 71.2%). The co-therapy group had more baseline peripheral arthritis and higher C-reactive-protein than the monotherapy group. One-year TNFi-retention rates (95%CI): 79% (78-79%) for TNFi monotherapy versus 82% (81-83%) with co-therapy (p< 0.001). Remission was obtained in 20% on monotherapy and 22% on co-therapy (p< 0.001); adjusted OR of 1.16 (1.07-1.25). Remission rates at 12 months were similar in patients with/without peripheral arthritis. CONCLUSION This large European study of axial SpA patients showed similar one-year treatment outcomes for TNFi monotherapy and csDMARD co-therapy, although considerable heterogeneity across countries limited the identification of certain subgroups (e.g. peripheral arthritis) that may benefit from co-therapy.