Table 1

Baseline characteristics of the patients

CharacteristicsOASIS
(n=161)*
GLAS
(n=264)*
P valuesOverall
(n=425)*
Age (years)49.1 (11.7)42.7 (11.9)<0.00145.2 (12.2)
Male sex112 (69.6%)179 (67.8%)0.704291 (68.5%)
Smoking—yes41/116 (35.3%)88/229 (38.4%)0.576129/345 (37.4%)
BMI26.5 (4.9)26.6 (4.3)0.81726.5 (4.5)
Symptom duration26.0 (11.5)17.2 (11.3)<0.00120.6 (12.2)
CRP (mg/L)12.3 (17.0)18.0 (18.3)0.00216.0 (18.1)
HLA-B27-positive129/156 (82.7%)204/257 (79.4%)0.409333/413 (80.6%)
Presence of (bridging) syndesmophytes74/109 (67.9%)107/197 (54.3%)0.021181/306 (59.2%)
Start anti-TNF-α treatment1/154 (0.6%)256/262 (97.7%)<0.001257/416 (61.8%)
BASDAI (0–103.3 (2.3)6.1 (1.7)<0.0015.1 (2.3)
BASFI (0–103.6 (2.7)5.6 (2.2)<0.0014.9 (2.6)
Patient GDA (0–10)3.4 (2.7)6.7 (1.9)<0.0015.5 (2.7)
Physician GDA (0–10)2.0 (1.6)4.7 (2.2)<0.0013.8 (2.4)
ASDAS-CRP2.5 (1.1)3.8 (0.8)<0.0013.3 (1.1)
ASQoL (0–18)5.8 (4.7)10.0 (4.1)<0.0018.7 (4.7)
Attrition ASQoL (≥2 missing final measures)42 (26.1%)57 (21.6%)0.28899 (23.3%)
Attrition ASDAS-CRP (≥2 missing final measures)62 (28.5%)56 (21.2%)<0.001118 (27.8%)
  • Values represent mean (SD) or number (%).

  • *Number of patients per group, unless otherwise stated due to missing values.

  • 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; OASIS, Outcome in Ankylosing Spondylitis International Study.