title: Tumor necrosis factor α inhibition in radiographic and nonradiographic axial spondyloarthritis: results from a large observational cohort.
abstract: OBJECTIVE
  To evaluate the baseline characteristics of patients with radiographic axial spondyloarthritis (SpA; ankylosing spondylitis [AS]) and patients with nonradiographic axial SpA, to investigate determinants of anti-tumor necrosis factor (anti-TNF) agent prescription on the background of a nonrestrictive reimbursement policy, and to assess the response to TNF inhibition.
  
  
  METHODS
  We compared the characteristics of radiographic axial SpA and nonradiographic axial SpA in 1,070 patients from the Swiss Clinical Quality Management (SCQM) Cohort who fulfilled the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA. By taking advantage of the situation that patients who are eligible for anti-TNF treatment are preferentially enrolled in the SCQM Cohort for patients with AS/axial SpA, we explored parameters leading to the initiation of anti-TNF treatment in single and multiple regression models and assessed treatment responses.
  
  
  RESULTS
  We confirmed a similar burden of disease (as determined by self-reported disease activity, impaired function, and quality of life) in patients with nonradiographic axial SpA (n = 232) and those with radiographic axial SpA (n = 838). Patients with radiographic axial SpA had higher median levels of acute-phase reactants and higher median AS Disease Activity Scores (ASDAS; 3.2 versus 3.0). Anti-TNF treatment was initiated in 363 patients with radiographic axial SpA and 102 patients with nonradiographic axial SpA, preferentially in those with sacroiliitis on magnetic resonance imaging, peripheral arthritis, a higher C-reactive protein (CRP) level, a higher ASDAS, and a higher Bath Ankylosing Spondylitis Disease Activity Index level. The ASAS criteria for 40% improvement responses at 1 year were higher in patients with radiographic axial SpA compared with those with nonradiographic axial SpA (48.1% versus 29.6%; odds ratio [OR] 2.2, 95% confidence interval [95% CI] 1.12-4.46, P = 0.02). The difference was smaller in the subgroups of patients with elevated baseline CRP levels (51.6% in patients with radiographic axial SpA versus 38.5% in those with nonradiographic axial SpA; OR 1.7, 95% CI 0.68-4.48, P = 0.29).
  
  
  CONCLUSIONS
  The indications for treatment with anti-TNF agents were comparable for patients with radiographic axial SpA and those with nonradiographic axial SpA. With the exception of patients with elevated CRP levels at baseline, higher rates of response to TNF inhibition were achieved in the group of patients with radiographic axial SpA than in the group with nonradiographic axial SpA.
authors: University Hospital, Zurich, Switzerland.
authors: Adrian
authors: A
authors: Ciurea
authors: Almut
authors: A
authors: Scherer
authors: Pascale
authors: P
authors: Exer
authors: Jürg
authors: J
authors: Bernhard
authors: Jean
authors: J
authors: Dudler
authors: Brigitte
authors: B
authors: Beyeler
authors: Rudolf
authors: R
authors: Kissling
authors: Daniel
authors: D
authors: Stekhoven
authors: Kaspar
authors: K
authors: Rufibach
authors: Giorgio
authors: G
authors: Tamborrini
authors: Bettina
authors: B
authors: Weiss
authors: Rüdiger
authors: R
authors: Müller
authors: Michael J
authors: MJ
authors: Nissen
authors: Beat A
authors: BA
authors: Michel
authors: Désirée
authors: D
authors: van der Heijde
authors: Maxime
authors: M
authors: Dougados
authors: Annelies
authors: A
authors: Boonen
authors: Ulrich
authors: U
authors: Weber
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D011859:Radiography; D013131:Spine / Q000000981:diagnostic imaging / Q000187:drug effects*; D025241:Spondylarthritis / Q000000981:diagnostic imaging / Q000188:drug therapy*; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging / Q000188:drug therapy*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha