Improvement definitions by the single domain disease activity measured by the Bath ankylosing spondylitis disease activity index and by the criteria of the Assessment in Ankylosing Spondylitis working group on different improvement levels
Criterion | Improvement definition | Infliximab trial | 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) | 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. The criterion which performed best is shown in bold. | ||||||
*Candidate criteria with χ2 values that are not significantly below reference criterion 1 (table 3). | ||||||
†Placebo response significantly above 10%. | ||||||
ASAS, Assessment in Ankylosing Spondylitis working group; BASDAI, Bath ankylosing spondylitis disease activity index; CI, confidence interval. | ||||||
Relative improvement of disease activity | ||||||
39 | ⩾20% change of the BASDAI | 37.14† | 85.29 | 16.79 | 4.72 to 32.04 | 12.52 |
40 | ⩾30% change of the BASDAI | 25.71† | 73.53 | 15.78 | 3.68 to 30.83 | 17.10 |
41 | ⩾40% change of the BASDAI | 8.57 | 64.71 | 23.52* | 10.16 to 39.30 | 21.31 |
42 | ⩾50% change of the BASDAI | 8.57 | 58.82 | 19.60* | 7.46 to 34.04 | 20.31 |
43 | ⩾60% change of the BASDAI | 5.71 | 38.24 | 10.72 | 2.45 to 22.19 | 15.67 |
44 | ⩾70% change of the BASDAI | 5.71 | 26.47 | 5.54 | 0.30 to 15.41 | 9.87 |
ASAS improvement criteria | ||||||
45 | ⩾20% and 10 units | 25.71† | 73.53 | 15.78 | 4.41 to 30.72 | 23.66 |
46 | ⩾30% and 10 units | 11.43 | 64.71 | 20.85* | 8.59 to 36.91 | 20.19 |
47 | ⩾40% and 20 units | 5.71 | 64.71 | 26.46* | 13.30 to 41.14 | 17.34 |
48 | ⩾50% and 20 units | 5.71 | 52.94 | 18.69 | 7.74 to 32.39 | 15.01 |
49 | ⩾60% and 30 units | 0.0 | 44.12 | 19.73 | 10.48 to 30.45 | 13.88 |
50 | ⩾70% and 30 units | 0.0 | 32.35 | 13.47 | 6.07 to 22.56 | 5.38 |