Response to bDMARD in the ‘efficacy population‘ according to the BASDAI/ASDAS category
| Variables | Overall | ASDAS ≥ 2.1 | ASDAS < 2.1 | ||
| (n=359) | BASDAI ≥ 4 (n=318) | BASDAI < 4 (n=31) | BASDAI ≥ 4 (n=1) | BASDAI < 4 (n=9) | |
| Probability of response (95% CI) | |||||
| Outcomes: 3 months | |||||
| ASAS20 | 60 (55; 64) | 60 (55; 65) | 58 (45; 70) | * | * |
| ASAS40 | 41 (36; 46) | 43 (38; 49) | 26 (13; 39) | * | 40 (7; 73) |
| ASAS PR | 26 (22; 30) | 22 (18; 26) | 61 (50; 72) | * | 44 (17; 72) |
| BASDAI50 | 61 (56; 66) | 62 (57; 67) | 58 (46; 70) | * | 44 (17; 72) |
| ASDAS CII | 61 (56; 66) | 62 (57; 67) | 68 (56; 80) | * | * |
| ASDAS MI | 37 (32; 41) | 38 (33; 43) | 32 (22; 42) | * | * |
| ASDAS ID | 29 (25; 33) | 25 (21; 30) | 61 (49; 74) | * | 56 (25; 86) |
| Outcomes: 6 months | |||||
| ASAS20 | 63 (58; 68) | 63 (57; 68) | 65 (49; 80) | * | * |
| ASAS40 | 40 (35; 44) | 42 (37; 47) | 23 (12; 34) | * | 40 (7; 73) |
| ASAS PR | 28 (24; 32) | 25 (21; 30) | 52 (39; 65) | * | * |
| BASDAI50 | 64 (59; 69) | 66 (61; 71) | 48 (35; 61) | * | 44 (17; 72) |
| ASDAS CII | 66 (62; 71) | 69 (64; 73) | 61 (50; 72) | * | * |
| ASDAS MI | 39 (34; 43) | 41 (36; 46) | 35 (26; 44) | * | * |
| ASDAS ID | 28 (24; 32) | 25 (21; 30) | 42 (30; 54) | * | * |
Overall (‘Efficacy population’): axSpA patients treated with bDMARD, with complete 6 months of follow-up and complete data on all response outcomes (every time point). Estimated probability of response across all subgroups according to BASDAI/ASDAS category of disease activity using a logistic regression model adjusted for age, gender, CRP and BASFI.
*Models fail to converge.
ASAS PR, ASAS partial remission; ASDAS, Ankylosing Spondylitis Disease Activity Score; ASDAS CII, ASDAS clinically important improvement; ASDAS ID, ASDAS inactive disease ; ASDAS MI, ASDAS major improvement; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; bDMARD, biologic disease-modifying antirheumatic drug; CRP, C reactive protein.