title: Impact of Dose Tapering of Tumor Necrosis Factor Inhibitor on Radiographic Progression in Ankylosing Spondylitis.
abstract: OBJECTIVE
  To investigate the impact of dose reduction of tumor necrosis factor inhibitor (TNFi) on radiographic progression in ankylosing spondylitis (AS).
  
  
  METHODS
  One hundred and sixty-five patients treated with etanercept or adalimumab were selected from a consecutive single-center observational cohort based on the availability of radiographs at baseline and after two- and/or four-years of follow up. Radiographs were assessed by two blinded readers using the modified Stokes AS Spinal Score (mSASSS). Radiographic progression in patients treated with standard-dose TNFi (standard-dose group, n = 49) was compared with patients whose dosage was tapered during the treatment (tapering group, n = 116) using linear mixed models.
  
  
  RESULTS
  Baseline characteristics between two groups were comparable except for higher BASDAI (7.1 vs. 6.3, p = 0.003) in the standard-dose group. At two years after the treatment, mean dose quotient (S.D.) of the tapering group was 0.59 (0.17). During follow up, rate of radiographic progression in overall patients was 0.90 mSASSS units/year. Radiographic progression over time between the two groups was similar at the entire group level. However, in the subgroup of patients with baseline syndesmophytes, progression occurred significantly faster in the tapering group after the adjustment for baseline status (1.23 vs. 1.72 mSASSS units/year, p = 0.023). Results were consistent when radiographic progression was assessed by the number of newly developed syndesmophytes (0.52 vs. 0.73/year, p = 0.047). Sensitivity analysis after multiple imputation of missing radiographs also showed similar results.
  
  
  CONCLUSIONS
  A dose tapering strategy of TNFi is associated with more rapid radiographic progression in AS patients who have syndesmophytes at baseline.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jun Won
authors.initials: JW
authors.lastname: Park
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hyun Mi
authors.initials: HM
authors.lastname: Kwon
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jin Kyun
authors.initials: JK
authors.lastname: Park
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Ja-Young
authors.initials: JY
authors.lastname: Choi
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Bong
authors.initials: EB
authors.lastname: Lee
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yeong Wook
authors.initials: YW
authors.lastname: Song
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Young
authors.identifier: http://orcid.org/0000-0001-6975-8627
authors.initials: EY
authors.lastname: Lee
mesh_terms: D000068879:Adalimumab / Q000494:pharmacology* / Q000627:therapeutic use; D000328:Adult; D015331:Cohort Studies; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D000068800:Etanercept / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011859:Radiography; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D000068879:Adalimumab; D000068800:Etanercept