Table 3

 Development of subset assessment of candidate improvement criteria for anti-TNFα agents in ankylosing spondylitis on the basis of the six domains: pain, patient global, function, inflammation, spinal mobility, and C reactive protein, modified by exchange of certain domains and instruments

CriterionImprovement definitionInfliximab trial (n = 69)Combined dataset etanercept and infliximab trial (n = 69) (χ2)
Per cent improving in the placebo treated group (n = 35)Per cent improving in the infliximab treated group (n = 34)χ295% CI of the χ2 value
Columns 3–7: infliximab trial, week 12. Last column: data from the combined dataset at week 6; to be comparable, n = 69 from n = 98 at random.
*Candidate criteria with χ2 values that are not significantly below reference criterion 1 (table 2).
AS, ankylosing spondylitis; BASMI, Bath ankylosing spondylitis metrology index; CI, confidence interval.
Five domains including the BASDAI instead of pain and inflammation
21⩾20%/10 units change in any four of five domains5.7167.6428.63*4.25 to 18.6922.04
22⩾20% change in any four of five5.7167.6528.63*14.34 to 44.3623.22
23⩾20% change in any four of five, including BASDAI5.7167.6428.63*14.34 to 44.3623.22
24⩾40%/20 units change in any three of five5.7158.8222.40*9.05 to 32.5324.72
25⩾40% change in any three of five5.7164.7126.46*12.97 to 40.7227.40
26⩾40% in 3 of 5 or ⩾30% in four of five, including BASDAI2.8664.7129.69*16.61 to 43.9223.43
Five domains for improvement in AS without the domain acute phase reactants
27⩾20%/10 units change in any four of five domains8.5773.5230.18*16.13 to 46.1825.88
28⩾20% change in any four of five8.5776.4732.63*17.26 to 48.4125.43
29⩾20% change in any four of five, including pain8.5776.4732.63*17.26 to 48.4125.43
30⩾40%/20 unit change in any three of five domains8.5764.7123.52*11.25 to 37.8718.69
31⩾40% change in any three of five8.5767.6525.63*12.72 to 40.3620.96
32⩾40% in three of five or ⩾30% in four of five, including pain8.5764.7123.52*10.88 to 38.2019.80
Six domains for improvement in AS with an exchange of BASMI for lateral lumbar flexion
33⩾20%/10 unit change in any five of six domains0.058.8228.99*17.81 to 42.3625.62
34⩾30%/10 unit change in any four of six5.7164.7126.46*13.86 to 41.1120.84
35⩾40%/20 unit change in any three of six8.5767.6525.63*12.72 to 40.3619.94
36⩾20% change in any five of six14.2976.4726.95*13.22 to 43.4128.03
37⩾30% change in any four of six5.7161.7624.38*12.27 to 38.4322.33
38⩾40% change in any three of six11.4370.5925.03*11.79 to 40.5229.24