Table 1 Baseline characteristics
Placebo (n = 78)5 mg/kg infliximab (n = 201)
Men, no. (%)68 (87.2%)157 (78.1%)
Age, years
    Mean (SD)40.3 (9.4)39.6 (10.6)
Disease duration, years
    N76201
    Mean (SD)11.9 (8.0)10.1 (8.7)
    Median (range)13.2 (0.3, 31.6)7.7 (0.3, 41.1)
HLA-B27 positive
    N78200
    No. (%)69 (88.5%)173 (86.5%)
Inflammation (average morning stiffness on a visual analogue scale 0–10 cm)
    N78201
    Mean (SD)6.9 (1.9)6.9 (2.3)
    Median (range)7.0 (0.8, 10.0)7.3 (0.2, 10.0)
Bone mineral density
Total spine bone mineral density (g/cm2)
    N73189
    Mean (SD)1.09 (0.25)1.01 (0.18)
    Median (range)1.02 (0.77, 2.01)1.01 (0.63, 1.64)
Spine T scores
    N72186
    Mean (SD)−0.28 (2.00)−0.96 (1.45)
    Median (range)−0.75 (−2.70, 7.40)−0.95 (−4.20, 3.60)
Total hip bone mineral density (g/cm2)
    N74192
    Mean (SD)0.95 (0.14)0.92 (0.14)
    Median (range)0.92 (0.69, 1.36)0.91 (0.59, 1.38)
Hip T scores
    N74190
    Mean (SD)−0.62 (0.91)−0.75 (0.97)
    Median (range)−0.70 (−2.20, 2.10)−0.80 (−3.30, 2.30)
Hip Z scores
    N74190
    Mean (SD)−0.42 (0.90)−0.54 (0.95)
    Median (range)−0.60 (−2.00, 2.24)−0.60 (−3.00, 2.50)
Syndesmophytes
Patients with syndesmophytes*54 (71.1%)122 (61.0%)
Regions with syndesmophytes†486 (27.6%)908 (19.3%)
Biomarker levels
IL-6 (pg/ml)
    N67187
    No. (%) with values ⩾LLOQ32 (47.8%)105 (56.1%)
    Mean (SD)11.4 (17.2)13.2 (20.0)
    Median (range)3.1 (3.1, 119.1)7.7 (3.1, 174.6)
VEGF (pg/ml)
    N75193
    No. (%) with values ⩾LLOQ75 (100%)191 (99.0%)
    Mean (SD)556.2 (385.6)520.4 (361.5)
    Median (range)473.5 (67.8, 2353.7)421.5 (29.8, 2067.5)
TGF-β (pg/ml)
    N75192
    No. (%) with values ⩾LLOQ75 (100%)192 (100%)
    Mean (SD)45.9 (11.5)46.8 (11.7)
    Median (range)46.7 (9.4, 85.9)48.1 (6.0, 90.3)
Osteocalcin (ng/ml)
    N73197
    No. (%) with values ⩾LLOQ71 (97.3%)197 (100%)
    Mean (SD)17.4 (8.7)18.4 (9.9)
    Median (range)15.8 (1.7, 41.3)16.9 (4.8, 73.5)
BAP (U/l)
    N73197
    No. (%) with values ⩾LLOQ73 (100%)197 (100%)
    Mean (SD)27.6 (10.1)26.7 (9.2)
    Median (range)25.4 (8.5, 63.5)25.0 (10.9, 62.1)
CTX (ng/ml)
    N72198
    No. (%) with values ⩾LLOQ66 (90.4%)184 (93.4%)
    Mean (SD)0.39 (0.24)0.39 (0.25)
    Median (range)0.34 (0.1, 1.6)0.33 (0.1, 1.8)
  • BAP, bone alkaline phosphatase; CTX, C-terminal cross-linking telopeptide of type I collagen; HLA, human leucocyte antigen; IL-6, interleukin-6; LLOQ, lower limit of quantification; TGF-β, transforming growth factor β; VEGF, vascular endothelial growth factor.

  • *Defined as a patient with at least one vertebral region that received an mSASSS score of ⩾2. See Methods for description of mSASSS scoring system.

  • †Defined as any region that received an mSASSS score of ⩾2.