Factors affecting discontinuation of adalimumab and etanercept therapy in anti-TNF-naïve patients with ankylosing spondylitis: Nationwide population-based cohort study

Abstract

Objectives. We investigated factors associated with discontinuation of anti-tumor necrosis factor (TNF) therapy in patients with ankylosing spondylitis (AS), who were anti-TNF-naïve and were given etanercept (ETN) or adalimumab (ADA).

Methods. This is a retrospective nationwide population-based cohort study. We identified 1401 anti-TNF-naïve patients with AS who initiated ETN (n = 441) or ADA (n = 960) and measured the duration of anti-TNF drug use. We recorded demographic and clinical data of all patients, and calculated adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazard regression analyses.

Results. Overall, the ADA and ETN groups had similar risk for drug discontinuation (HR: 0.83; 95% CI: 0.63–1.08). In each group, concomitant use of methotrexate (MTX) or a non-steroidal anti-inflammatory drug was associated with a lower risk of discontinuation. Subgroup analysis indicated that concomitant MTX use reduced risk of discontinuation of ADA (HR: 0.54; 95% CI: 0.40–0.74), but not ETN (HR: 1.03; 95% CI: 0.65–1.63).

Conclusions. This study of anti-TNF-naïve patients with AS indicated that users of ADA and ETN had similar overall risk of drug discontinuation. However, patients taking ADA with MTX had a lower risk of discontinuation than those taking ADA alone.

Keywords:

• Adalimumab
• Ankylosing spondylitis
• Etanercept
• Methotrexate
• Treatment discontinuation
• Tumor necrosis factor-α

Acknowledgements

We would like to thank the Biostatistics Task Force of Taichung Veterans General Hospital, Taichung, Taiwan, ROC, for assistance with statistical analysis. We thank the members of the BNHI, Department of Health, and the National Health Research Institutes for providing and managing the NHIRD, respectively.

Funding statement

None.

Conflict of interest

None.

Supplementary Table 1.