Table 2.
Disease characteristics of AS and OA controls.
| Ankylosing Spondylitis | n = 193 |
|---|---|
| HLA-B27-positive (n, %) | 156 (82) |
| Disease activity and severity | |
| ASDAS-CRP (mean ± SD) | 2.1 ± 1.0 |
| BASMI (mean ± SD) | 4.1 ± 1.8 |
| BASFI (mean ± SD) | 3.7 ± 2.4 |
| BASDAI (median; IQR) | 3.1 (1.6–5.0) |
| Time since diagnosis, years (mean ± SD) | 22 ± 12 |
| Osteoarthritis | n = 74 |
| Affected joints | |
| Knee (n, %) | 61 (82) |
| Hip (n, %) | 18 (24) |
| Poly-osteoarthritis (n, %) | 60 (81) |
| Prosthesis (n, %) | 15 (20) |
| WOMAC (mean ± SD) | 42 (23) |
| Time since diagnosis (median; IQR) | 5 (2–8) |
Values are displayed as mean ± standard deviation (SD), median with corresponding interquartile range (IQR) or frequencies with corresponding percentages (%). AS = ankylosing spondylitis, OA = osteoarthritis, HLA = Human leukocyte antigen, ASDAS-CRP = Ankylosing Spondylitis Disease Activity Score-C-reactive protein, BASMI = Bath Ankylosing Spondylitis Metrology Index, BASFI = Bath Ankylosing Spondylitis Functional Index, BASDAI = Bath Ankylosing Spondylitis Disease Activity Index, WOMAC = Western Ontario and McMaster Universities Osteoarthritis.