Factors associated with TNFi continuation in naïve patients
| Baseline characteristics* | Patients continuing the first TNFi | ||||
| Yes (n=88) | No (n=154) | Univariate HR (95% CI) | Multivariate HR (95% CI) | P value | |
| Age (years) (≥45 years old) | 14 (15.9) | 22 (14.3) | 1.1 (0.7 to 1.7) | _ | _ |
| Sex (male) | 52 (59.1) | 52 (33.8) | 2.0 (1.4 to 2.7) | 1.5 (1.1 to 2.1) | 0.04 |
| Symptoms duration (years) | 1.5 (0.9) | 1.6 (0.9) | 0.9 (0.8 to 1.1) | _ | _ |
| Employment (blue collar) | 13/87 (14.9) | 25/153 | 1.1 (0.7 to 1.6) | _ | _ |
| Education (university) | 45 (51.1) | 81 (52.6) | 1.1 (0.7 to 1.4) | _ | _ |
| HLA-B27 positive | 57 (64.8) | 79 (51.3) | 1.6 (1.1 to 2.1) | 1.4 (1.1 to 2.0) | 0.03 |
| MRI sacroiliitis positive | 46/85 (54.1) | 51/152 (86.2) | 1.8 (1.3 to 2.6) | _ | _ |
| Radiographic sacroiliitis positive | 27/85 (31.8) | 26/153 (17.0) | 1.9 (1.2 to 2.9) | _ | _ |
| History of good NSAID response | 79 (89.8) | 128/153 (83.7) | 1.1 (0.7 to 1.7) | _ | _ |
| History of arthritis | 31 (35.2) | 50/152 (32.9) | 1.2 (0.8 to 1.6) | _ | _ |
| History of dactylitis | 12 (13.6) | 23/153 (15.0) | 1.1 (0.7 to 1.7) | _ | _ |
| History of enthesitis | 54 (61.4) | 115 (74.7) | 1.5 (1.0 to 2.1) | 1.4 (0.9 to 2.0) | 0.11 |
| CRP (mg/L) | 13.1 (14.4) | 10.9 (19.5) | 1.0 (1.0 to 1.1) | _ | _ |
| ASDAS-CRP (per point) | 2.9 (0.9) | 3.2 (0.8) | 0.8 (0.7 to 1.0) | 0.8 (0.6 to 0.9) | 0.02 |
| BASDAI (range 0–10) | 4.5 (1.8) | 5.8 (1.5) | 0.8 (0.7 to 0.9) | _ | _ |
| Presence of at least one objective sign of inflammation or structural damage | 53/85 (62.4) | 61/149 (40.9) | 2.0 (1.4 to 2.8) | 1.7 (1.2 to 2.4) | 0.004 |
| BASFI (range 0–10) | 3.1 (2.1) | 4.4 (2.1) | 0.9 (0.8 to 0.9) | _ | _ |
| Centre in which TNFi inclusion rate was over 20% over follow-up | 59 (67.0) | 126 (81.8) | 1.6 (1.1 to 2.4) | 1.3 (0.8 to 1.9) | 0.36 |
| Centre in which TNFi prescription rate was over 30% over follow-up | 71 (80.7) | 117 (76.0) | 1.2 (0.8 to 1.6) | _ | _ |
*Values are presented as mean (SD) and n (%) for continuous and categorical variables, respectively.
ASDAS-CRP, Ankylosing Spondylitis Disease Activity Score using CRP; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C reactive protein; NSAID, non-steroidal anti-inflammatory drugs; TNFi, tumour necrosis factor inhibitor.