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Prediction of a major clinical response (BASDAI 50) to tumour necrosis factor α blockers in ankylosing spondylitis
  1. M Rudwaleit1,
  2. J Listing2,
  3. J Brandt1,
  4. J Braun3,
  5. J Sieper1
  1. 1Rheumatology, Department of Medicine, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany
  2. 2Epidemiology, Deutsches RheumaForschungszentrum, Berlin, Germany
  3. 3Rheumazentrum Ruhrgebiet, Herne, Germany
  1. Correspondence to:
    Dr M Rudwaleit
    Medizinische Klinik I, Charité–Universitäts-medizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany;


Background: TNFα blockers have been shown to be highly efficacious in patients with active ankylosing spondylitis (AS).

Objective: To identify parameters predicting the clinical response to TNF blockers in AS.

Methods: Patients with active AS participated in two placebo controlled, randomised trials conducted in Germany with infliximab (n = 69) and etanercept (n = 30), respectively. For inclusion in either trial patients had to have high disease activity (BASDAI ⩾4) and a spinal pain score (numerical rating scale 0–10) ⩾4 despite treatment with NSAIDs. A major clinical response was defined as a 50% improvement of the initial BASDAI (BASDAI 50) after 12 weeks’ treatment with active drug. Logistic regression likelihood ratio tests (univariate and multivariate), Student’s t test, and χ2 tests were performed.

Results: Univariate analysis showed the following to be predictors of a major response (BASDAI 50) to treatment: shorter disease duration (p = 0.003); lower BASFI (p = 0.007); younger age (p = 0.009); raised ESR (p = 0.033); raised CRP (p = 0.035). After adjustment for disease duration, BASFI, ESR, and CRP, but not age, remained significantly associated. After adjustment for disease duration and for BASFI, ESR, CRP, and in addition, a higher BASDAI were significantly associated with response. The best multivariate model built by stepwise regression contained the covariables disease duration, BASFI, BASDAI, and CRP.

Conclusion: A shorter disease duration, younger age, and a lower BASFI are predictors of a major clinical response to TNF blockers in active AS. Raised CRP and a higher BASDAI may also be valuable predictors. These data need to be confirmed in further studies.

  • tumour necrosis factor blockers
  • ankylosing spondylitis
  • spondyloarthropathies
  • response
  • anti-tumour necrosis factor
  • AS, ankylosing spondylitis
  • ASAS, Ankylosing Spondylitis Assessment Group
  • BASDAI, Bath Ankylosing Spondylitis Disease Activity Index
  • BASFI, Bath Ankylosing Spondylitis Functional Index
  • BASMI, Bath Ankylosing Spondylitis Metrology Index
  • BASRI, Bath Ankylosing Spondylitis Radiology Index
  • CRP, C reactive protein
  • DMARD, disease modifying antirheumatic drug
  • ESR, erythrocyte sedimentation rate
  • LRT, likelihood ratio test
  • MRI, magnetic resonance imaging
  • NSAID, non-steroidal anti-inflammatory drug
  • TNFα, tumour necrosis factor α

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