Table 2

Sensitivity and specificity of ASDAS cut-off values for disease activity states and levels of improvement against several external criteria in NOR-DMARD and ASSERT

ASDAS cut-offs and external criterionTimepointSESPnSESPnSESPn
ASDAS <1.3:
 ASAS partial remission3 Months66.788.831078.386.331080.692.3219
6 Months60.091.219282.291.219287.290.0219
 Patient global <13 Months69.990.731071.285.231082.189.6220
6 Months67.585.620780.082.620781.386.1219
 Physician global <13 Months44.488.330556.587.8305
6 Months71.985.619984.482.6199
ASDAS <2.1:
 Patient global <33 Months80.487.331091.780.331081.790.6220
6 Months83.689.720793.685.620787.283.5220
 Physician global <33 Months59.388.730570.083.9305
6 Months84.389.719994.185.6199
ASDAS >3.5:
 Patient global >6Baseline74.879.244259.488.344285.258.0223
 Physician global >6Baseline79.259.443267.971.5432
ΔASDAS ≥1.1:
 Better or much better3 Months62.786.725263.880.0252
6 Months61.796.816460.290.3164
 ASAS203 Months84.583.825886.280.325883.687.0220
6 Months83.379.316585.981.616584.190.3219
ΔASDAS ≥2.0:
 Much better3 Months56.490.225259.093.7252
6 Months53.890.216450.091.1164
 ASAS403 Months64.993.925861.094.525886.580.8220
6 Months60.493.816554.793.816583.790.2219
  • ASAS20 and ASAS40 response criteria are based on four independent domains: spinal pain, physical function measured by the BASFI, patient global assessment and inflammation measured as the mean of the last two BASDAI questions (severity and duration of morning stiffness); ASAS20 treatment response is defined as improvement of ≥20% and ≥1 unit (range 0–10) in at least three of the four above domains, and no worsening of ≥20% and ≥1 unit in the remaining fourth domain; ASAS40 treatment response is defined as improvement of ≥40% and ≥2 units in at least three of the four above domains, and no worsening in the remaining fourth domain; ASAS partial remission criteria are fulfilled if the value for all four domains is below 2. Range of patient and physician global assessment is 0–10.

  • ASAS, Assessment of SpondyloArthritis international Society; ASDAS, Ankylosing Spondylitis Disease Activity Score; ASSERT, Ankylosing Spondylitis Study for the Evaluation of Recombinant Infliximab Therapy; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C reactive protein; ESR, erythrocyte sedimentation rate; NOR-DMARD, Norwegian register of disease modifying antirheumatic drugs.