Characteristics of the total group of patients at baseline, stratified for the presence or absence of syndesmophytes at baseline, and comparisons between groups of patients with and without new (bridging) syndesmophytes at 4 years
| Baseline syndesmophytes | New (bridging) syndesmophytes at 4 years | ||||||
|---|---|---|---|---|---|---|---|
| Total group at baseline (n=132) | Absent (n=51) | Present (n=81) | p Value | Absent (n=69) | Present (n=63) | p Value | |
| Male (%) | 94 (71) | 30 (59) | 64 (79) | 0.01 | 42 (61) | 52 (83) | <0.01 |
| Age (years) | 44.4 (12.1) | 38.0 (10.4) | 48.4 (11.4) | <0.01 | 41.1 (11.6) | 48.0 (11.6) | 0.01 |
| HLA-B27 positive (%)* | 106 (80) | 37 (73) | 69 (85) | 0.18 | 56 (81) | 50 (80) | 0.53 |
| Hip involvement (%)* | 30 (23) | 9 (18) | 21 (26) | 0.29 | 13 (19) | 17 (27) | 0.26 |
| Duration of symptoms (years)* | 21.1 (11.7) | 16.4 (9.1) | 24.0 (12.2) | <0.01 | 19.7 (11.3) | 22.7 (11.3) | 0.16 |
| Duration of disease since diagnosis (years)† | 11.7 (9.3) | 8.9 (5.1) | 13.6 (10.6) | <0.01 | 10.6 (8.2) | 13.0 (10.3) | 0.13 |
| BASDAI (0–10) | 3.5 (2.1) | 3.4 (1.8) | 3.6 (2.3) | 0.64 | 3.5 (2.0) | 3.5 (2.3) | 0.88 |
| BASFI (0–10) | 3.4 (2.5) | 2.4 (2.1) | 4.0 (2.3) | <0.01 | 2.9 (2.2) | 3.9 (2.6) | 0.03 |
| ASDAS‡ | 2.6 (1.1) | 2.3 (1.0) | 2.8 (1.1) | 0.02 | 2.4 (1.0) | 2.8 (1.1) | 0.06 |
| CRP§ | 13.6 (15.4) | 11.5 (16.0) | 14.9 (14.9) | 0.02 | 12.0 (14.5) | 15.4 (16.2) | 0.08 |
| Elevated CRP (%) | 49 (40) | 13 (25) | 36 (44) | 0.04 | 22 (32) | 27 (43) | 0.13 |
| ESR¶ | 12.4 (14.3) | 10.4 (10.8) | 13.7 (16.1) | 0.12 | 10.1 (11.1) | 15.1 (17.0) | 0.03 |
| Presence of baseline syndesmophytes (%) | 25 (36) | 56 (89) | <0.01 | ||||
Mean (SD) or number of patients (%).
↵* Data available in 128 patients.
↵† Data available in 127 patients.
↵‡ Data available in 115 patients.
↵§ Data available in 122 patients.
↵¶ Data available in 124 patients.
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C reactive protein (normal value <10 mg/dl); ESR, erythrocyte sedimentation rate; HLA-B27, human leucocyte antigen B27.