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Table 1 Baseline patient characteristics

From: Low bone mineral density predicts the formation of new syndesmophytes in patients with axial spondyloarthritis

Variable Total patients (n = 119) New syndesmophytes at 2 years p value
No (n = 97) Yes (n = 22)
Age (years) 35 ± 9 34 ± 10 38 ± 8 0.075
Male sex 91 (77) 74 (76) 17 (77) 1.000
BMI (kg/m2) 23.2 ± 3.4 22.9 ± 3.2 24.4 ± 4.1 0.072
Current smoking 36 (30) 25 (26) 11 (50) 0.038
Alcohol ≥ 3 units/day 3 (3) 3 (3) 0 (0) 1.000
Symptom duration (years) 8.6 ± 7.6 7.9 ± 7.3 11.6 ± 8.0 0.035
Family history of axSpA 12 (10) 12 (12) 0 (0) 0.120
HLA B27-positive 110 (92) 90 (93) 20 (91) 0.671
Peripheral arthritis 27 (23) 22 (23) 5 (23) 1.000
Radiographic sacroiliitis 90 (76) 70 (72) 20 (91) 0.097
BASDAI score (range 0–10) 3.9 ± 2.1 3.9 ± 2.0 3.7 ± 2.7 0.683
BASFI score 1.7 ± 2.1 1.7 ± 2.2 1.8 ± 1.8 0.722
ESR (mm/h) 23 ± 20 23 ± 20 23 ± 19 0.960
CRP (mg/L) 9.1 ± 14.9 8.9 ± 15.2 10.2 ± 14.1 0.703
ASDAS-ESR 2.6 ± 1.1 2.6 ± 1.1 2.5 ± 1.3 0.707
ASDAS-CRP 2.2 ± 1.3 2.2 ± 1.2 2.2 ± 1.5 0.883
mSASSS 7.6 ± 14.3 5.7 ± 13.0 15.8 ± 17.1 0.015
Number of syndesmophytes 2.3 ± 4.8 1.6 ± 4.3 5.0 ± 6.0 0.021
Presence of syndesmophytes 34 (29) 21 (22) 13 (59) 0.001
Patients on NSAIDs 106 (89) 86 (89) 20 (91) 1.000
Patients on sulfasalazine 42 (35) 34 (35) 8 (36) 1.000
Patients on TNF inhibitors 36 (30) 27 (28) 9 (41) 0.303
Patients on bisphosphonate 2 (2) 2 (2) 0 (0) 1.000
Patients on calcium 17 (14) 11 (11) 6 (27) 0.085
Patients on vitamin D 18 (15) 12 (12) 6 (27) 0.099
BMD (g/cm2)
 Lumbar spine 1.16 ± 0.17 1.17 ± 0.16 1.13 ± 0.22 0.949
 Femoral neck 0.94 ± 0.14 0.94 ± 0.14 0.92 ± 0.16 0.401
 Total hip 0.98 ± 0.15 0.99 ± 0.15 0.95 ± 0.15 0.338
Low BMD (Z score ≤ −2.0)
 Any site 19 (16) 12 (12) 7 (32) 0.047
 Lumbar spine 15 (13) 10 (10) 5 (23) 0.150
 Femoral neck 3 (3) 1 (1) 2 (12) 0.070
 Total hip 5 (4) 3 (3) 2 (9) 0.233
  1. Data presented as n (%) or mean ± standard deviation
  2. BMI body mass index, axSpA axial spondyloarthritis, BASDAI Bath Ankylosing Spondylitis Disease Activity Index, BASFI Bath Ankylosing Spondylitis Functional Index, ESR erythrocyte sedimentation rate, CRP C-reactive protein, ASDAS Ankylosing Spondylitis Disease Activity Score, mSASSS Modified Stoke Ankylosing Spondylitis Spinal Score, NSAID non-steroidal anti-inflammatory drug, TNF tumour necrosis factor, BMD bone mineral density