Biomarker levels at baseline and percentage changes in biomarkers from baseline to week 22 in patients stratified according to improvement in ASDAS and BASDAI response
| Improvement in ASDAS | BASDAI response | |||||||
|---|---|---|---|---|---|---|---|---|
| No/clinically important (<2.00) N=24 | Major (≥2.0) N=23 | Non-responders (<50% or 20 mm) N=18 | Responders (≥50% or 20 mm) N=35 | |||||
| Week 0 | % Week 0–22 | Week 0 | % Week 0–22 | Week 0 | % Week 0–22 | Week 0 | % Week 0–22 | |
| CRP (mg/l) | 9 (2.6–16)*** | −48 (−67; −15)*** | 26 (13–64) | −91 (−97; −82) | 10 (3.5; 19)* | −51 (−76; −20)** | 24 (11; 42) | −85 (−94; −61) |
| IL-6 (ng/l) | 4.2 (3.0–9)* | −46 (−76; −15)*** | 10 (4.6–22) | −86 (−94; −75) | 6 (3.8; 14) | −70 (−83; −13)* | 7 (3.7; 21) | −80 (−92; −60) |
| VEGF (ng/l) | 51 (32–104) | −10 (−34; −13)** | 98 (50–166) | −42 (−64; −25) | 51 (25; 93)* | −15 (−44; 29) | 83 (40; 183) | −38 (−58; −6) |
| YKL-40 (μg/l) | 54 (42–109)* | −17 (−43; 0) | 40 (29–60) | −9 (−39; 0) | 64 (45; 145)** | −18 (−44; 2) | 42 (32; 60) | −12 (−32; 0) |
| CTX-II (ng/mmol) | 280 (175–534)* | −18 (−41; 19) | 517 (383–873) | −20 (−58; −3) | 419 (254; 818) | −12 (−28; 40) | 485 (279; 853) | −25 (−58; −3) |
| Aggrecan (µg/l) | 588 (417–739) | −3 (−8; 12)* | 566 (501–726) | 12 (1; 32) | 587 (486; 721) | 11 (−8; 14) | 563 (457; 726) | 8 (−2; 23) |
| MMP-3 (µg/l) | 23 (14–32)* | −8 (−23; 5)* | 35 (19–122) | −38 (80; 8) | 24 (13; 46) | −5 (−33; 24) | 25 (17; 60) | −19 (−62; −3) |
| COMP (µg/l) | 1.58 (1.34–1.85) | 5 (−6; 9) | 1.55 (1.40–1.80) | 10 (−5; 19) | 1.50 (1.28; 1.85) | 3 (−10; 7) | 1.70 (1.45; 1.90) | 9 (−3; 20) |
| CTX-I (µg/l) | 0.32 (0.23–0.44) | −9 (−25; 20) | 0.38 (0.26–0.52) | −2 (−30; 28) | 0.31 (0.23; 0.40) | 5 (−22; 30) | 0.38 (0.24; 0.48) | −7 (−32; 20) |
| Osteocalcin (µg/l) | 24.8 (21.3–37.8) | −5 (−24; 5)*** | 25.8 (21.4–40.1) | 21 (3; 35) | 24.2 (18.8; 40.2) | 2 (−21; 15) | 24.5 (19.4; 30.9) | 9 (−11; 27) |
Biomarker levels are median (IQR). The Mann–Whitney test was used for comparison of baseline biomarker levels in patients with no/clinically important versus major improvement in ASDAS and in BASDAI responders versus BASDAI non-responders. The same groups were compared regarding percentage changes in biomarker levels from baseline to week 22 by use of the Mann–Whitney test: *p<0.05; **p<0.01; ***p<0.001. BASDAI analyses included 53 patients at week 22 and 44 patients at week 46 (missing values in three patients). The analyses of ASDAS comprised 48 patients at week 22 and 37 patients at week 46, because ASDAS could not be determined in four patients at baseline, in five patients at week 22 and in 10 patients at week 46. Of the 60 patients included, seven patients were excluded before week 22, and a further six patients were excluded before week 46.
ASDAS, ankylosing spondylitis disease activity score; BASDAI, Bath ankylosing spondylitis disease activity index; COMP, cartilage oligomeric matrix protein; CRP, C-reactive protein; CTX-I, C-terminal cross-linking telopeptide of type I collagen; CTX-II, C-terminal crosslinking telopeptide of type II collagen; IL-6, interleukin 6; MMP-3, matrix metalloproteinase 3; VEGF, vascular endothelial growth factor.