Table 2.
Baseline clinical features and measures of disease activity, physical function, and spinal mobility of all patients with AS who continued vs. discontinued index TNFi therapy by the second follow-up visit
| Characteristica | Overall, N = 155 | Continued TNFi, n = 118 | Discontinued TNFi, n = 37 | P value |
|---|---|---|---|---|
| Enthesitis, n (%) | 45 (29.0) | 34 (28.8) | 11 (29.7) | 0.92 |
| SPARCC Enthesitis Index score (1–16) among patients with enthesitis | 3.5 (2.8) | 3.6 (2.9) | 3.2 (2.6) | 0.67 |
| Dactylitis, n (%) | 8 (5.2) | 8 (6.8) | 0 | 0.10 |
| Dactylitis count (1–20) among patients with dactylitis | 3.3 (4.0) | 3.3 (4.0) | 0 | 0.49 |
| History of dactylitis, n (%) | 6 (3.9) | 4 (3.4) | 2 (5.4) | 0.58 |
| Tender joint count (0–68) | 2.5 (5.8) | 2.6 (6.3) | 1.9 (4.0) | 0.54 |
| Swollen joint count (0–66) | 0.4 (1.4) | 0.4 (1.4) | 0.5 (1.2) | 0.74 |
| Patients with swollen joint count ≥ 1, n (%) | 25 (16.5) | 17 (14.8) | 8 (21.6) | 0.33 |
| BASDAI score (0–10) | 3.8 (2.5) | 3.5 (2.4) | 4.8 (2.6) | 0.01 |
| BASDAI score ≥ 4, n (%) | 69 (44.5) | 48 (42.5) | 21 (60.0) | 0.07 |
| BASFI score (0–10) | 3.2 (2.9) | 2.8 (2.7) | 4.2 (3.1) | 0.01 |
| Spinal mobility measures | ||||
| Occiput-to-wall distance, cm | 4.3 (6.9) | 4.4 (7.1) | 4.0 (6.3) | 0.76 |
| Lateral lumbar flexion (average of right and left), cm | 22.8 (18.9) | 23.6 (19.6) | 20.1 (16.4) | 0.39 |
| ASDAS | 1.9 (0.8) | 1.9 (0.8) | 1.8 (0.7) | 0.64 |
| ASDAS disease activity, n (%) | ||||
| Inactive (< 1.3) | 21 (21.0) | 15 (19.7) | 6 (25.0) | 0.72 |
| Moderate (≥ 1.3 to < 2.1) | 45 (45.0) | 35 (46.1) | 10 (41.7) | |
| High (≥ 2.1 to < 3.5) | 31 (31.0) | 23 (30.3) | 8 (33.3) | |
| Very high (≥ 3.5) | 3 (3.0) | 3 (4.0) | 0 | |
| CRP, mg/l | 2.1 (5.8) | 2.5 (6.5) | 1.0 (2.1) | 0.22 |
| Elevated CRP, n (%) | 23 (14.8) | 16 (13.6) | 7 (18.9) | 0.42 |
| ESR, mm/h | 11.2 (15.2) | 9.8 (12.9) | 16.2 (20.7) | 0.08 |
aAll values were calculated based on available data and are presented as “mean (SD)” unless otherwise stated. All variables had < 20% missing data except for ASDAS (n = 100), CRP (n = 109), and ESR (n = 99)
AS ankylosing spondylitis, ASDAS Ankylosing Spondylitis Disease Activity Score, BASDAI Bath Ankylosing Spondylitis Disease Activity Index, BASFI Bath Ankylosing Spondylitis Functional Index, CRP C-reactive protein, ESR erythrocyte sedimentation rate, SPARCC Spondyloarthritis Research Consortium of Canada, TNFi tumor necrosis factor inhibitor