Should over-treatment of axial spondyloarthritis with biologics remain a concern after the issue of the new ASAS criteria? Data from REGISPONSERBIO (Spanish Register of Biological Therapy in Spondyloarthritides).

OBJECTIVES: To study whether disease status at treatment initiation has changed after the issue of the ASAS classification criteria. METHODS: REGISPONSERBIO registers patients with axial spondyloarthritis (axSpA) on biological treatment since 2013. It includes patients starting biological treatment (incident) or already on biological therapies (prevalent). Patients in both groups were compared in terms of: age at disease onset and at treatment start, disease duration, gender, HLA-B27, body mass index (BMI), BASDAI, BASFI, C-reactive protein, ESR, metrological data, ASQoL, WAPAI, extra-articular manifestations, comorbidities, radiological study, type of biological treatment and concomitant treatments. RESULTS: 256 patients were included, of whom 174 (65%) were already on biologic therapy. Compared to incident patients, prevalent patients started treatment with longer disease duration (15 vs. 8.6 years; p<0.001), a higher proportion of them were men (83% vs. 67%; p=0.01), a smaller proportion of them showed non-radiographic axial spondylarthritis (nr-axSpA)(17% vs. 32%; p<0.01), and a higher proportion had HLAB27 (85% vs. 73%; p=0.02). There were no statistically significant differences in terms of disease activity, degree of disability, quality of life, or prevalence of extra-articular manifestations. CONCLUSIONS: Data suggest that, after the issue of the new classification criteria for SpA, biological therapy is being administered earlier than previously in SpA patients and in a higher proportion of patients with nr-axSpA. However, this change in prescribing profile, apparently, has not caused an over-treatment, as patients do not seem to have a lower disease burden than prior to the issue of the criteria.