title: Factors affecting discontinuation of adalimumab and etanercept therapy in anti-TNF-naïve patients with ankylosing spondylitis: Nationwide population-based cohort study.
abstract: OBJECTIVE
  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.
authors.affiliation: a Department of Medical Research , Taichung Veterans General Hospital , Taichung , Taiwan.|b School of Medicine, National Yang-Ming University , Taipei , Taiwan.|c Division of Allergy, Immunology and Rheumatology, Department of Internal Medicine , Taichung Veterans General Hospital , Taichung , Taiwan.|d Institute of Public Health and Community Medicine Research Center, National Yang-Ming University , Taipei , Taiwan.|e Institute of Hospital and Health Care Administration, National Yang-Ming University , Taipei , Taiwan.|f School of Medicine, Chung-Shan Medical University , Taichung , Taiwan.|g Institute of Biomedical Science and Rong Hsing Research Center for Translational Medicine, Chung-Hsing University , Taichung , Taiwan.
authors.forename: Hsin-Hua
authors.initials: HH
authors.lastname: Chen
authors.affiliation: a Department of Medical Research , Taichung Veterans General Hospital , Taichung , Taiwan.|b School of Medicine, National Yang-Ming University , Taipei , Taiwan.|c Division of Allergy, Immunology and Rheumatology, Department of Internal Medicine , Taichung Veterans General Hospital , Taichung , Taiwan.|g Institute of Biomedical Science and Rong Hsing Research Center for Translational Medicine, Chung-Hsing University , Taichung , Taiwan.
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Chen
authors.affiliation: a Department of Medical Research , Taichung Veterans General Hospital , Taichung , Taiwan.
authors.forename: Kuo-Lung
authors.initials: KL
authors.lastname: Lai
authors.affiliation: c Division of Allergy, Immunology and Rheumatology, Department of Internal Medicine , Taichung Veterans General Hospital , Taichung , Taiwan.
authors.forename: Ching-Heng
authors.initials: CH
authors.lastname: Lin
authors.affiliation: h School of Health Care Administration, Taipei Medical University , Taipei , Taiwan.
authors.forename: Chao-Hsiung
authors.initials: CH
authors.lastname: Tang
authors.affiliation: b School of Medicine, National Yang-Ming University , Taipei , Taiwan.|c Division of Allergy, Immunology and Rheumatology, Department of Internal Medicine , Taichung Veterans General Hospital , Taichung , Taiwan.|f School of Medicine, Chung-Shan Medical University , Taichung , Taiwan.|g Institute of Biomedical Science and Rong Hsing Research Center for Translational Medicine, Chung-Hsing University , Taichung , Taiwan.|i Department of Medical Education , Taichung Veterans General Hospital , Taichung , Taiwan.
authors.forename: Der-Yuan
authors.initials: DY
authors.lastname: Chen
keywords: Adalimumab; Ankylosing spondylitis; Etanercept; Methotrexate; Treatment discontinuation; Tumor necrosis factor-α