Table 1 Baseline characteristics of young and late onset ankylosing spondylitis patients at the time of enrollment.

From: Effectiveness and drug retention of biologic disease modifying antirheumatic drugs in Korean patients with late onset ankylosing spondylitis

Variable

N (%) or median with IQR

YOAS

(N = 1472)

LOAS

(N = 236)

p valuea

Age (year-old)

29.0 [22.1; 37.1]

57.0 [54.0; 61.1]

< 0.001

Symptom duration (months)

11.6 [30.5; 37.1]

11.4 [32.2; 60.1]

0.092

Male

1170 (79.5%)

144 (61.0%)

< 0.001

BMI

23.3 [21.1; 25.7]

23.6 [21.4; 25.6]

0.456

Smoking

  

< 0.001

Ex-smoker

289 (19.6%)

62 (26.3%)

 

Current smoker

464 (31.5%)

34 (14.4%)

 

Never

719 (48.8%)

140 (59.3%)

 

Biologic naïve

1127 (76.6%)

207 (87.7%)

< 0.001

Right sacroiliitis grade

2.61[2.56; 2.67]

2.59[2.46; 2.72]

0.768

Left sacroiliitis grade

2.6[2.55; 2.65]

2.56[2.43; 2.69]

0.577

Swelling joint count

0.53[0.44; 0.63]

1.59[1.53; 1.65]

0.026

Tender joint count

0.53[0.44; 0.63]

1.11[0.61; 1.61]

0.001

Features of ASAS Classification Criteria of axSpA

Acute Inflammation on MRI highly suggestive of sacroiliitis associated with SpA

332 (22.6%)

61 (25.8%)

0.536

Definite radiographic sacroiliitis according to modified NY criteria

1320 (89.7%)

214 (90.7%)

0.721

Inflammatory back pain

1250 (84.9%)

192 (81.4%)

0.209

Arthritis

392 (26.6%)

95 (40.3%)

< 0.001

Enthesitis

231 (15.7%)

39 (16.5%)

0.847

Uveitis

127 (8.6%)

26 (11.0%)

0.487

Dactylitis

21 (1.4%)

6 (2.5%)

0.414

Psoriasis

38 (2.6%)

8 (3.4%)

0.694

Crohn’s colitis

8 (0.5%)

0 (0.0%)

0.518

Good response to NSAIDs

509 (34.6%)

86 (36.4%)

0.694

Family history for SpA

164 (11.1%)

27 (11.4%)

0.486

HLA-B27

1244 (84.5%)

175 (74.2%)

< 0.001

Elevated CRP

1005 (68.3%)

163 (69.1%)

0.464

Comorbidity

Hypertension

164 (11.1%)

94 (39.8%)

< 0.001

Ischemic Heart Disease

15 (1.0%)

7 (3.0%)

0.002

Hyperlipidemia

185 (12.6%)

47 (19.9%)

0.009

Congestive Heart failure

3 (0.2%)

0 (0.0%)

0.076

Arrhythmia

11 (0.7%)

5 (2.1%)

0.118

Peripheral vascular disorder

0(0%)

0(0%)

1.000

Stroke

2 (0.1%)

0 (0.0%)

1.000

Osteoporosis

38 (2.6%)

29 (12.3%)

< 0.001

Diabetes without complication

36 (2.4%)

30 (12.7%)

< 0.001

Diabetes with complication

7 (0.5%)

2 (0.8%)

0.804

Hyperthyroidism

5 (0.3%)

2 (0.8%)

0.559

Hypothyroidism

7 (0.5%)

9 (3.8%)

< 0.001

Renal failure

6 (0.4%)

6 (2.5%)

0.001

Peptic ulcer

28 (1.9%)

5 (2.1%)

1.000

Liver disease

24 (1.6%)

3 (1.3%)

0.897

Tuberculosis

4 (0.3%)

0 (0.0%)

0.939

Anemia

254 (17.3%)

110 (46.6%)

< 0.001

Disease associated parameters

BASDAI

6.1 [4.8; 7.3]

6.4 [5.0; 7.7]

0.083

PGA

6.3[6.2; 6.4]

6.6[6.3; 6.9]

0.028

ESR

27.5 [13.0; 51.0]

47.5 [20.0; 76.0]

< 0.001

CRP

1.0 [0.3; 2.5]

1.7 [0.4; 4.0]

0.001

ASDAS-ESR

3.6 [2.9; 4.3]

4.1 [3.3; 4.9]

< 0.001

ASDAS-CRP

3.6 [2.9; 4.3]

3.8 [3.0; 4.7]

0.002

BASFI

2.8 [1.0; 5.2]

3.7 [1.8; 6.1]

0.078

  1. IQR, interquartile range; YOAS, Young Onset Ankylosing spondylitis (< 50-year-old); LOAS, Late Onset Ankylosing Spondylitis (≥ 50-year-old); BMI, bone mass index; ASAS, assessment in ankylosing spondylitis; axSpA, axial spondyloarthritis; MRI, magnetic resonance imaging; NY, New York; NSAIDs, non-steroidal anti-inflammatory drugs; CRP, C-reactive protein. BASDAI, Bath ankylosing spondylitis disease activity index; PGA, patient’s global assessment; ASDAS, Ankylosing Spondylitis Disease Activity Score; ESR, erythrocyte sediment rate; BASFI, Bath Ankylosing Spondylitis Functional Index.
  2. aComparing each group with Kruskal–Wallis test or χ2 test.
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