Skip to main content

Table 1 Clinical characteristics of the cohort and comparison of characteristics according to clusters

From: A cluster analysis of patients with axial spondyloarthritis using tumour necrosis factor alpha inhibitors based on clinical characteristics

  All patients (n = 1042) Axial group (n = 828) Extra-axial group (n = 214) p-value
Age at starting TNFi (years, %) 38.32 (13.08) 38.18 (12.76) 38.85 (14.28) 0.618
Sex (male, %) 793 (76.1) 651 (78.6) 142 (66.4) 0.001
Late onset (age ≥ 40 years, %) 329 (31.6) 247 (29.8) 82 (38.3) 0.034
Long disease duration (≥ 2 years, %) 426 (40.9) 380 (45.9) 46 (21.5) < 0.001
HLA-B27 positivity (%) 929 (89.2) 740 (89.4) 189 (88.3) 0.782
Inflammatory back pain (%) 887 (85.1) 704 (85.0) 183 (85.5) 0.943
Radiographic sacroiliitis (%) 934 (89.6) 745 (90.0) 189 (88.3) 0.618
Peripheral arthritis (%) 388 (37.2) 203 (24.5) 185 (86.4) < 0.001
Enthesitis (%) 218 (20.9) 68 (8.2) 150 (70.1) < 0.001
Uveitis (%) 222 (21.3) 168 (20.3) 54 (25.2) 0.197
Psoriasis (%) 27 (2.6) 16 (1.9) 11 (5.1) 0.029
IBD (%) 13 (1.2) 9 (1.1) 4 (1.9) 0.618
Good response to NSAIDs (%) 358 (34.4) 212 (25.6) 146 (68.2) < 0.001
csDMARD use (%) 107 (10.3) 75 (9.1) 32 (15.0) 0.029
NSAID use (%) 904 (86.8) 714 (86.2) 190 (88.8) 0.486
SJC 0.65 (2.28) 0.50 (2.37) 1.21 (1.80) < 0.001
TJC 1.04 (3.06) 0.71 (2.67) 2.32 (4.00) < 0.001
BASDAI 6.03 (1.91) 5.94 (1.92) 6.37 (1.81) 0.005
BASFI 3.47 (2.56) 3.42 (2.56) 3.66 (2.56) 0.305
ASDAS-ESR 3.74 (1.03) 3.65 (1.00) 4.05 (1.08) < 0.001
ASDAS-CRP 3.66 (1.02) 3.61 (1.00) 3.87 (1.07) 0.003
ESR (mm/h) 37.87 (30.03) 35.65 (28.76) 46.46 (33.21) < 0.001
CRP (mg/dL) 2.27 (2.95) 2.11 (2.74) 2.89 (3.60) 0.006
  1. TNFi tumour necrosis factor alpha inhibitor, HLA human leucocyte antigen, IBD inflammatory bowel disease, NSAID non-steroidal anti-inflammatory drug, csDMARD conventional synthetic disease-modifying anti-rheumatic drug, SJC swollen joint count, TJC tender joint count, BASDAI Bath Ankylosing Spondylitis Disease Activity Index, BASFI Bath Ankylosing Spondylitis Functional Index, ESR erythrocyte sedimentation rate, CRP C-reactive protein, ASDAS-ESR Ankylosing Spondylitis Disease Activity Score based on ESR, ASDAS-CRP Ankylosing Spondylitis Disease Activity Score based on CRP