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

Criterion	Improvement definition	Infliximab trial (n = 69)				Combined dataset etanercept and infliximab trial (n = 69) (χ²)
Criterion	Improvement definition	Per cent improving in the placebo treated group (n = 35)	Per cent improving in the infliximab treated group (n = 34)	χ²	95% 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 domains	5.71	67.64	28.63*	4.25 to 18.69	22.04
22	⩾20% change in any four of five	5.71	67.65	28.63*	14.34 to 44.36	23.22
23	⩾20% change in any four of five, including BASDAI	5.71	67.64	28.63*	14.34 to 44.36	23.22
24	⩾40%/20 units change in any three of five	5.71	58.82	22.40*	9.05 to 32.53	24.72
25	⩾40% change in any three of five	5.71	64.71	26.46*	12.97 to 40.72	27.40
26	⩾40% in 3 of 5 or ⩾30% in four of five, including BASDAI	2.86	64.71	29.69*	16.61 to 43.92	23.43

Five domains for improvement in AS without the domain acute phase reactants
27	⩾20%/10 units change in any four of five domains	8.57	73.52	30.18*	16.13 to 46.18	25.88
28	⩾20% change in any four of five	8.57	76.47	32.63*	17.26 to 48.41	25.43
29	⩾20% change in any four of five, including pain	8.57	76.47	32.63*	17.26 to 48.41	25.43
30	⩾40%/20 unit change in any three of five domains	8.57	64.71	23.52*	11.25 to 37.87	18.69
31	⩾40% change in any three of five	8.57	67.65	25.63*	12.72 to 40.36	20.96
32	⩾40% in three of five or ⩾30% in four of five, including pain	8.57	64.71	23.52*	10.88 to 38.20	19.80

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 domains	0.0	58.82	28.99*	17.81 to 42.36	25.62
34	⩾30%/10 unit change in any four of six	5.71	64.71	26.46*	13.86 to 41.11	20.84
35	⩾40%/20 unit change in any three of six	8.57	67.65	25.63*	12.72 to 40.36	19.94
36	⩾20% change in any five of six	14.29	76.47	26.95*	13.22 to 43.41	28.03
37	⩾30% change in any four of six	5.71	61.76	24.38*	12.27 to 38.43	22.33
38	⩾40% change in any three of six	11.43	70.59	25.03*	11.79 to 40.52	29.24