title: Sensitivity and discriminatory ability of the Ankylosing Spondylitis Disease Activity Score in patients treated with etanercept or sulphasalazine in the ASCEND trial.
abstract: OBJECTIVE
  The Ankylosing Spondylitis Disease Activity Score (ASDAS) is a new composite clinical tool combining subjective and objective measures. Using data from the randomized double-blind Ankylosing Spondylitis Study Comparing Enbrel with Sulfasalazine Dosed Weekly (ASCEND) trial, we tested ASDAS validity and assessed its capacity to discriminate between treatment effects and change-from-baseline improvements.
  
  
  METHODS
  These post hoc analyses were conducted in patients who received etanercept (50 mg/week) or SSZ (≤ 3 g/day) for 16 weeks. The ASDAS was tested for its capacity to discriminate between those who achieved and did not achieve Assessment of Spondyloarthritis International Society (ASAS) partial remission and ASAS20. Week 16 adjusted treatment differences and effect sizes of improvement from baseline of 42 outcomes were calculated.
  
  
  RESULTS
  Means for ASDAS were less than half in patients with ASAS partial remission compared with patients without partial remission across the entire study population (1.2 vs 2.6; P<0.0001). Patients who achieved ASAS20 had greater mean changes from baseline in ASDAS than those who did not (-1.8 vs -0.3; P<0.0001). ASDAS was consistently shown to have one of the highest discriminatory capacities compared with other measurements (including subjective measurements) regardless of normal vs high CRP, presence or absence of peripheral arthritis and high vs very high ASDAS at baseline. As a dichotomous variable using different thresholds for improvement and disease severity, ASDAS had slightly better discriminatory capacity than all corresponding ASAS measures.
  
  
  CONCLUSIONS
  ASDAS is a validated and highly discriminatory tool for the detection of significant differences between treatments for AS as well as for detecting a significant improvement from baseline with etanercept and SSZ.
authors: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands. mail@dvanderheijde.nl
authors: Désirée
authors: D
authors: van der Heijde
authors: Jürgen
authors: J
authors: Braun
authors: Maxime
authors: M
authors: Dougados
authors: Joachim
authors: J
authors: Sieper
authors: Ronald
authors: R
authors: Pedersen
authors: Annette
authors: A
authors: Szumski
authors: Andrew S
authors: AS
authors: Koenig
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D004311:Double-Blind Method; D000068800:Etanercept; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use*; D012074:Remission Induction / Q000379:methods; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000175:diagnosis* / Q000188:drug therapy*; D012460:Sulfasalazine / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D012460:Sulfasalazine; D000068800:Etanercept