Baseline characteristics of patients within each HRQoL—disease activity trajectory
| Characteristics | Trajectory 1 Low impact (n=55)* | Trajectory 2 Moderate impact (n=105)* | Trajectory 3 High impact with major improvement (n=86)* | Trajectory 4 High impact with some improvement (n=124)* | Trajectory 5 Very high impact (n=55)* | P values |
| Patients from OASIS | 40 (72.7%) | 62 (59.0%) | 4 (2.5%) | 37 (29.8%) | 18 (32.7%) | <0.001 |
| Patients from GLAS | 15 (27.3%) | 43 (41.0%) | 82 (95.3%) | 87 (70.2%) | 37 (67.3%) | <0.001 |
| ASDAS-CRP | 1.6 (0.7) | 2.8 (0.8) | 4.0 (0.7) | 3.7 (0.8) | 4.1 (0.7) | <0.001 |
| ASQoL (0–18) | 1.6 (2.0) | 5.4 (2.7) | 9.0 (3.5) | 11.1 (2.8) | 14.6 (2.4) | <0.001 |
| Attrition ASQoL (≥2 missing final measures) | 16 (29.1%) | 17 (16.2%) | 17 (19.8%) | 32 (25.8%) | 17 (30.9%) | 0.146 |
| Attrition ASDAS-CRP (≥2 missing final measures) | 20 (36.4%) | 26 (24.8%) | 17 (19.8%) | 36 (29.0%) | 19 (34.5%) | 0.158 |
| Age (years) | 43.9 (12.4) | 46.0 (12.7) | 40.9 (10.7) | 47.9 (11.3) | 45.1 (13.7) | 0.001 |
| Male sex | 46 (83.6%) | 71 (67.6%) | 62 (72.1%) | 83 (66.9%) | 29 (52.7%) | 0.012 |
| Smoking—yes | 16/42 (38.1%) | 23/85 (27.1%) | 26/74 (35.1%) | 44/98 (44.9%) | 20/46 (43.5%) | 0.129 |
| BMI | 25.5 (3.7) | 26.6 (4.9) | 25.9 (3.9) | 26.8 (4.3) | 27.7 (5.4) | 0.210 |
| Symptom duration (years) | 20.3 (10.9) | 21.4 (12.1) | 17.0 (10.9) | 22.2 (13.1) | 21.3 (12.6) | 0.043 |
| CRP (mg/L) | 7.1 (6.9) | 9.9 (9.8) | 21.8 (18.9) | 18.5 (21.5) | 21.1 (21.1) | <0.001 |
| HLA-B27-positive | 50/54 (92.6%) | 73/103 (70.9%) | 72/82 (87.8%) | 94/119 (79.0%) | 44/55 (80.0%) | 0.007 |
| Presence of (bridging) syndesmophytes | 16/39 (41.0%) | 45/73 (61.6%) | 38/70 (54.3%) | 64/90 (71.1%) | 18/34 (52.9%) | 0.017 |
| Start anti-TNF-α treatment | 15/54 (27.8%) | 41/101 (40.6%) | 81/86 (94.2%) | 85/120 (70.8%) | 35/55 (63.6%) | <0.001 |
| BASDAI (0–10) | 1.7 (1.3) | 4.0 (2.0) | 6.0 (1.4) | 5.9 (1.6) | 7.3 (1.5) | <0.001 |
| BASFI (0–10) | 1.8 (1.8) | 3.8 (2.3) | 5.2 (2.1) | 6.1 (1.8) | 7.0 (1.9) | <0.001 |
| Patient GDA (0–10) | 1.8 (1.7) | 4.3 (2.4) | 6.9 (1.9) | 6.3 (2.0) | 7.3 (1.7) | <0.001 |
| Physician GDA (0–10) | 2.1 (2.0) | 2.8 (1.9) | 4.5 (2.2) | 4.4 (2.3) | 4.6 (2.3) | <0.001 |
Values represent mean (SD) or number (%).
*Number of patients per group at baseline.
anti-TNF-α treatment, antitumour necrosis factor α treatment; ASDAS-CRP, Ankylosing Spondylitis Disease Activity Score—C reactive protein; ASQoL, Ankylosing Spondylitis Quality of Life; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BMI, body mass index; CRP, C reactive protein; GDA, Global Disease Activity Score; GLAS, Groningen Leeuwarden Ankylosing Spondylitis; HLA-B27, Human Leucocyte Antigen B27; HRQoL, health-related quality of life; OASIS, Outcome in Ankylosing Spondylitis International Study.