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Table 1 Baseline characteristics of the AS study population

From: The effect of three years of TNF alpha blocking therapy on markers of bone turnover and their predictive value for treatment discontinuation in patients with ankylosing spondylitis: a prospective longitudinal observational cohort study

Number of patients 111   
Age (yrs) 42.2 ± 10.3   
Gender (male) (n, %) 78 (70)   
Duration of symptoms (yrs) 16 (1 to 49)   
Time since diagnosis (yrs) 9 (0 to 37)   
HLA-B27+ (n, %) 88 (81)   
History of IBD (n, %) 11 (10)   
History of uveitis (n, %) 31 (28)   
History of psoriasis (n, %) 9 (8)   
Peripheral arthritis (n, %) 21 (19)   
Current NSAID use (n, %) 98 (88)   
Current DMARD use (n, %) 26 (23)   
BASDAI (range 0 to 10) 6.1 ± 1.7 BASDAI ≥ 4 (n, %) 98 (88)
ASDASCRP 3.8 ± 0.8 ASDASCRP ≥ 2.1 (n, %) 105 (96)
Physician's GDA (range 0 to 10) 5 (1 to 9)   
Patient's GDA (range 0 to 10) 7 (1 to 10)   
ESR (mm/h) 22 (2 to 90) Increased ESR (n, %) 86 (78)
CRP (mg/l) 15 (2 to 99) Increased CRP (n, %) 84 (76)
BASFI (range 0 to 10) 6.1 ± 2.0   
Chest expansion (cm) 3.0 (0.5 to 10.0)   
Modified Schober test (cm) 2.9 (0.1 to 7.0)   
Occiput to wall distance (cm) 5.0 (0.0 to 28.0)   
Lateral lumbar flexion L (cm) 8.7 ± 4.1   
Lateral lumbar flexion R (cm) 8.4 ± 4.3   
ASQoL (range 0 to 18) 10 ± 4   
BALP (U/L) 17.2 (1.6 to 36.5)   
BALP Z-score 0.28 (-2.59 to 5.16)   
PINP (μg/l) 45.6 (16.0 to 98.0)   
PINP Z-score 0.35 (-1.75 to 3.63)   
sCTX (pg/ml) 206.0 (13.4-657.1)   
sCTX Z-score -0.34 (-2.58 to 4.01)   
LS BMD T-score -0.58 ± 1.41 Osteopenia LS (n, %) 34 (34)
   Osteoporosis LS (n, %) 9 (9)
LS BMD Z-score   LS Z-score ≤ -2.0 (n, %) 9 (9)
Hip BMD T-score -0.53 ± 1.12 Osteopenia hip (n, %) 38 (37)
   Osteoporosis hip (n, %) 2 (2)
Hip BMD Z-score   Hip Z-score ≤ -2.0 (n, %) 4 (4)
  1. Values are mean ± SD or median (range) unless otherwise indicated.
  2. AS, Ankylosing Spondylitis; ASDAS, Ankylosing Spondylitis Disease Activity Score; BALP, bone-specific-alkaline phosphatase; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BMD, bone mineral density; CRP, C-reactive protein; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; GDA, global disease activity; HLA-B27+, human leukocyte antigen B27 positive; IBD, inflammatory bowel disease; L, left; LS, lumbar spine;. NSAID, non-steroidal anti-inflammatory drug; PINP, procollagen type 1 N-terminal peptide; R, right; sCTX, serum C-telopeptide of type I collagen