Patient demographics and baseline characteristics
| Enrolment period | ||||
|---|---|---|---|---|
| Parameter | 2005–2007 N=135 | 2008–2013 N=168 | Total N=303 | p Value* (between groups) |
| Demographics | ||||
| Male gender, n (%) | 82 (60.7) | 107 (63.7) | 189 (62.4) | 0.634 |
| Age, years, mean (SD) | 45.6 (11.6) | 45.7 (11.9) | 45.6 (11.7) | 0.958 |
| Baseline characteristics | ||||
| Disease duration, years, mean (SD) | 11.1 (10.8) | 8.2 (9.2) | 9.6 (10.0) | 0.011 |
| Unemployed, n (%)† | 62 (45.9) | 77 (46.7) | 139 (46.3) | 0.908 |
| Unemployed due to disability, n (%)‡ | 29 (46.8) | 37 (48.1) | 66 (47.5) | >0.999 |
| Financial coverage, n (%)† | ||||
| Public | 38 (28.1) | 67 (41.9) | 105 (35.6) | 0.012 |
| Private | 71 (52.6) | 70 (43.8) | 141 (47.8) | |
| Public and private | 10 (7.4) | 16 (10.0) | 26 (8.8) | |
| Other | 16 (11.9) | 7 (4.4) | 23 (7.8) | |
| IFX dose (mg/kg), mean (SD) | 4.3 (1.0) | 4.4 (1.2) | 4.4 (1.1) | 0.372 |
| Number of previous DMARDs, mean (SD) | 0.7 (1.1) | 0.5 (0.8) | 0.6 (0.9) | 0.078 |
| Previous therapy, n (%) | ||||
| DMARDs | 56 (41.5) | 56 (33.3) | 112 (37.0) | 0.152 |
| NSAIDs | 97 (71.9) | 125 (74.4) | 222 (73.3) | 0.695 |
| Corticosteroids | 37 (27.4) | 46 (27.4) | 83 (27.4) | >0.999 |
| Methotrexate | 33 (24.4) | 40 (23.8) | 73 (24.1) | 0.894 |
| Concomitant therapy, n (%) | ||||
| DMARDs | 37 (27.4) | 50 (29.8) | 87 (28.7) | 0.702 |
| NSAIDs | 72 (53.3) | 99 (58.9) | 171 (56.4) | 0.352 |
| Corticosteroids | 9 (6.7) | 6 (3.6) | 15 (5.0) | 0.288 |
| Methotrexate | 28 (20.7) | 41 (24.4) | 69 (22.8) | 0.492 |
| NSAIDs, previous or concomitant therapy, n (%) | 116 (85.9) | 130 (77.4) | 246 (81.2) | 0.075 |
| ASDAS, mean (SD) | 3.9 (0.9) | 3.7 (1.1) | 3.8 (1.0) | 0.103 |
| ASDAS disease activity, n (%)† | ||||
| Inactive (<1.3) | 0 (0.0) | 4 (3.1) | 4 (1.7) | 0.160 |
| Moderate (1.3–2.0) | 1 (1.0) | 3 (2.3) | 4 (1.7) | |
| High (2.1–3.5) | 34 (33.0) | 50 (38.5) | 84 (36.1) | |
| Very high (>3.5) | 68 (66.0) | 73 (56.2) | 141 (60.5) | |
| BASDAI, mean (SD) | 6.5 (1.9) | 6.4 (2.2) | 6.4 (2.0) | 0.490 |
| BASFI, mean (SD) | 6.3 (2.2) | 6.1 (2.5) | 6.2 (2.4) | 0.447 |
| HAQ-DI, mean (SD) | 1.3 (0.6) | 1.2 (0.6) | 1.2 (0.6) | 0.318 |
| AM stiffness§, minutes, mean (SD) | 79.0 (38.9) | 70.1 (42.4) | 74.1 (41.0) | 0.064 |
| MDGA (NRS: 0–10), mean (SD) | 7.0 (1.6) | 6.3 (2.1) | 6.6 (1.9) | 0.001 |
| PtGA (NRS: 0–10), mean (SD) | 6.6 (2.3) | 6.7 (2.4) | 6.7 (2.3) | 0.811 |
| Back pain (NRS: 0–10), mean (SD) | 6.7 (2.5) | 6.5 (2.6) | 6.6 (2.6) | 0.623 |
| ESR (mm/h), mean (SD) | 30.0 (23.1) | 19.9 (18.1) | 24.5 (21.1) | <0.001 |
| CRP (mg/L), mean (SD) | 20.4 (23.9) | 16.7 (25.7) | 18.3 (24.9) | 0.243 |
*Statistically significant values are marked in italics.
†Percentages based on patients who provided a response: employment (n=300); financial coverage (n=295); ASDAS disease activity (n=233).
‡Percentage based on total number of unemployed patients (n=139).
§Capped at 120 min.
AM stiffness, morning stiffness; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C-reactive protein; DMARDs, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; HAQ-DI, Health Assessment Questionnaire Disease Index; IFX, infliximab; MDGA, physician global assessment of disease activity; NRS, Numeric Rating Scale; NSAIDs, non-steroidal anti-inflammatory drugs; PtGA, patient global disease activity.