Early axial spondyloarthritis according to the ASAS consensus definition: characterisation of patients and effectiveness of a first TNF inhibitor in a large observational registry.

Objective: To characterise the population fulfilling the Assessment of SpondyloArthritis international Society (ASAS) consensus definition of early axial spondyloarthritis (axSpA) and to determine the effectiveness of a first tumour necrosis factor inhibitor (TNFi) in early versus established axSpA in a large observational registry.
Methods: A total of 3064 patients with axSpA in the Swiss Clinical Quality Management registry with data on duration of axial symptoms were included (≤2 years=early axSpA, N=658; >2 years=established axSpA, N=2406). Drug retention was analysed in patients starting a first TNFi in early axSpA (N=250) versus established axSpA (N=874) with multiple-adjusted Cox proportional hazards models. Adjusted logistic regression analyses were used to determine the achievement of the ASAS criteria for 40% improvement (ASAS40) at 1 year.
Results: Sex distribution, disease activity, impairments of function and health-related quality of life were comparable between patients with early and established axSpA. Patients with established disease were older, had more prevalent axial radiographical damage and had a higher impairment of mobility. A comparable TNFi retention was found in early versus established disease after adjustment for age, sex, human leucocyte antigen-B27 status, education, body mass index, smoking, elevated C reactive protein and sacroiliac inflammation on MRI (HR 1.05, 95% CI 0.78 to 1.42). The adjusted ASAS40 response was similar in the two groups (OR 1.09, 95% CI 0.67 to 1.78). Results were confirmed in the population fulfilling the ASAS classification criteria.
Conclusion: Considering the recent ASAS definition of early axSpA, TNFi effectiveness seems comparable in early versus established disease.
Competing Interests: Competing interests: The SCQM Foundation is supported by the Swiss Society of Rheumatology and by AbbVie, AstraZeneca, Eli Lilly, iQone Healthcare, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Samsung Bioepis and Sandoz. AC received honoraria for lectures from AbbVie and Novartis. AR-R received consulting fees from AbbVie, Janssen and Pfizer; honoraria for lectures from AbbVie, Janssen, Novartis and Pfizer; as well as support for attending meetings from Janssen and Pfizer. AS received consulting fees from Pfizer and support for attending meetings from Gilead. BM received speaking fees from AbbVie, Janssen, Novartis and Pfizer, as well as support for attending meetings from Janssen. DK received a research grant from AbbVie, honoraria for presentations from AbbVie and Eli Lilly, support for attending meetings from Janssen and Eli Lilly, as well as payments for participation in advisory boards from AbbVie, Eli Lilly, Janssen, Novartis, Pfizer and Roche. MJN received consulting and/or speaking fees from AbbVie, Eli Lilly, Janssen, Novartis and Pfizer, as well as a research grant from Novartis. OD received consulting fees from AbbVie. PE received financial support from UCB to attend a meeting. RM received honoraria for lectures or presentations from AbbVie, Eli Lilly, Janssen, Gilead and Pfizer. TH received royalties from Curmed, payments for lectures and presentations from Pfizer, Fresenius Kabi, AbbVie, Merck Sharp & Dohme, Galapagos, Eli Lilly and Novartis. He participated in advisory boards for DETECTRA and holds stock or stock options of Atreon SA and Vtuls. AG, KB, MA and RB declare they have no conflicts of interest.
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