Baseline descriptive data for 2577 patients with AS starting a first ever TNFi 1 July 2006 to 31 December 2015 in the nationwide Swedish Rheumatology Quality register
| Baseline descriptive data | |
| Age, mean (SD) | 44 (13.2) |
| Sex, men n (%) | 1819 (71) |
| CRP, n (%) | |
| CRP <10 | 921 (36) |
| CRP ≥10 | 919 (36) |
| Missing | 737 (29) |
| BASDAI, n (%) | |
| <4 | 174 (7) |
| ≥4 | 511 (20) |
| Missing, n (%) | 1892 (73) |
| ASDAS-CRP | |
| Mean (SD) | 3.3 (1.04) |
| Missing n (%)* | 1979 (77) |
| Peripheral arthritis phenotype n (%) | 163 (18) |
| Treatment, n (%) | |
| csDMARD | 630 (24) |
| NSAID | 2128 (83) |
| Oral corticosteroids | 236 (9) |
| Type of TNFi, n (%) | |
| Infliximab | 908 (35) |
| Adalimumab | 778 (30) |
| Etanercept | 480 (19) |
| Golimumab | 325 (13) |
| Certolizumab pegol | 86 (3) |
| SpA manifestations, n (%) | |
| Anterior uveitis | 706 (27) |
| Psoriasis | 156 (6) |
| Inflammatory bowel disease | 177 (7) |
| Comorbidities, n (%) | |
| Cardiovascular disease | 550 (21) |
| Affective disorder | 325 (13) |
| Chronic lung disease | 225 (9) |
| Malignancy | 131 (5) |
| Diabetes | 82 (3) |
| Chronic kidney disease | 31 (1) |
| Socioeconomic factors | |
| Annual household income €, mean (SD) | 23 810 (14914) |
| Length of formal education n (%) | |
| ≤9 years | 318 (12) |
| 10–12 years | 1130 (44) |
| ≥13 years | 758 (29) |
| Missing | 371 (14) |
| Rate of sick leave/disability pension n (%)† | |
| 0% | 1162 (53) |
| 1%–49% | 554 (25) |
| 50%–99% | 239 (11) |
| 100% | 252 (11) |
*The rates of missing data for ASDAS are partly systematic, since it was introduced in the register during the study period.
†Net days of sick leave or disability pension during 1 year before start first TNFi.
AS, ankylosing spondylitis; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; csDMARD, conventional synthetic disease modifying anti-rheumatic drugs; NSAID, non-steroidal anti-inflammatory drug; SpA, spondyloarthritis; TNFi, tumour necrosis factor alpha inhibitor.