Background Anti-TNF alpha (TNFi) drug survival is one of the relevant outcome measure in rheumatological diseases.
Objectives Objective of this study was to compare TNFi drug survival in ankylosing spondylitis (AS) and axial spondyloarthritis (AxSpA).
Methods HUR-BIO (Hacettepe University Rheumatology Biologic Registry) is a single center biological registry since 2005. HUR-BIO biological dataset included demographic data, education level, co-morbidities, smoking, BMI, HLA-B27, switch ratio, baseline and follow-up disease activity parameters (such as BASDAI, BASFI, CRP, ESR, global VAS). Patients with lost of follow-up searched regarding to last TNFi prescription date with either local computer system or national social security institution database. Inition and last date of TNFi were noted from those systems. First TNFi drug switch date (either advers event or inefficacy) was accepted as main variable for drug survival. Kaplan-Meier plots and log rank tests were used to assess drug survival. HUR-BIO is not sponsored by any pharmaceutical company. Missing data ratio of baseline disease activity measures were 38.5% at BASDAI, 22.1% at ESR, 23.9% at CRP and 60.6% at BASFI.
Results There were 874 patients (747 AS and 127 AxSpA). Mean age was 40.7±11.4 years old. Overall, 533 (61%) of patients were male, mean disease duration was 8.3±7.1 years and mean symptom duration was 12.8±8.9 years. Initial biological drugs were etanercept 346 (39.6%), infliximab 270 (30.9%) and adalimumab 258 (29.5%). Overall, initial biological drugs were continued at 497 (56.9%) patients. Of 245 (29.7%) patients had at least one biological switch. First biological drug survival was more frequent at male sex (61.4% vs 49.8%, p=0.001) and patients with highest ESR level (31.6 (23.7) vs 27.8 (22.3) mm/hour, p=0.041). In logistic regression analysis, male sex had tendency of better TNFi drugs survival [OR 1.65 (95%CI 0.96-2.83), p=0.070]. Patients with use usage of etanercept had tendency of more frequent drugs survival than monoclonal antibodies (log-rank p=0.057) (Table and Figure 1). Retention rate was similar at both AS and AxSpA patients.
Conclusions In this single center observational registry, etanercept had tendency of better drug retention rate than monoclonal antibodies. Overall, anti-TNF drugs retention rate was well both AS and AxSpA than rheumatoid arthritis. On the other hand, certain confounder factors such as baseline disease activity, functional status were not known in whole patients, thus our results should evaluate in this limitation
Disclosure of Interest None declared