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Table 2 Sensitivity analyses performed after multiple imputation of missing covariate data. Models with and without ASDAS at treatment start to address the potential issue of confounding by indication

From: Site-specific assessment of spinal radiographic progression improves detection of TNF blocker-associated disease modification in axial spondyloarthritis: longitudinal observational data from the Swiss Clinical Quality Management Registry

  

A. Model without ASDAS

B. Model with ASDAS

Spinal segment

Variable

OR

95% CI

P value

OR

95% CI

P value

Cervical spine

TNFi use before radiographic interval yes/no

0.43

0.24; 0.77

0.004

0.42

0.23; 0.76

0.004

Total mSASSS at start of each radiogr. interval

1.05

1.03; 1.07

 < 0.001

1.05

1.03; 1.07

 < 0.001

Male sex

1.29

0.68; 2.43

0.44

1.28

0.68; 2.42

0.45

Symptom duration (5 years)

1.22

1.07; 1.40

0.004

1.22

1.07; 1.40

0.003

Current smoking

1.24

0.69; 2.23

0.47

1.23

0.68; 2.22

0.50

HLA-B27

0.72

0.33; 1.58

0.42

0.72

0.33; 1.59

0.42

Number of exercise sessions per week

0.99

0.87; 1.12

0.86

0.99

0.87; 1.12

0.85

Peripheral arthritis

1.18

0.63; 2.23

0.60

1.17

0.62; 2.22

0.63

NSAID use at start of each radiographic interval

0.52

0.26; 1.02

0.06

0.51

0.26; 1.01

0.054

BMI 25–30 (reference: BMI < 25)

1.46

0.81; 2.63

0.21

1.45

0.80; 2.62

0.22

BMI > 30 (reference: BMI < 25)

1.08

0.47; 2.50

0.85

1.07

0.46; 2.49

0.88

Length of radiographic interval

0.87

0.47; 1.61

0.67

0.88

0.47; 1.62

0.67

ASDAS at start of TNFi and ASDAS at inclusion

for non-treated patients

   

1.05

0.75; 1.46

0.79

Lumbar spine

TNFi use before radiographic interval yes/no

0.85

0.51; 1.41

0.53

0.72

0.43; 1.21

0.22

Total mSASSS at start of each radiogr. interval

1.04

1.02; 1.06

 < 0.001

1.04

1.03; 1.06

 < 0.001

Male sex

2.85

1.51; 5.35

0.001

2.83

1.51; 5.31

0.001

Symptom duration (5 years)

1.08

0.95; 1.22

0.27

1.09

0.96; 1.24

0.19

Current smoking

0.78

0.47; 1.29

0.33

0.73

0.44; 1.22

0.22

HLA-B27

0.68

0.36; 1.26

0.22

0.69

0.37; 1.28

0.24

Number of exercise sessions per week

1.01

0.91; 1.13

0.81

1.01

0.91; 1.12

089

Peripheral arthritis

1.13

0.65; 1.97

0.66

1.05

0.59; 1.85

0.87

NSAID use at start of each radiographic interval

1.25

0.67; 2.34

0.48

1.18

0.63; 2.21

0.60

BMI 25–30 (reference: BMI < 25)

1.42

0.81; 2.49

0.23

1.37

0.77; 2.44

0.28

BMI > 30 (reference: BMI < 25)

2.06

1.06; 4.01

0.03

1.90

0.99; 3.67

0.06

Length of radiographic interval

1.55

0.82; 2.93

0.18

1.57

0.82; 3.02

0.17

ASDAS at start of TNFi and ASDAS at inclusion

for non-treated patients

   

1.31

0.94; 1.82

0.11

  1. Progression defined as an increase in mSASSS of at least 1 unit in 2 years. ASDAS, Ankylosing Spondylitis Disease Activity Score; BMI, body mass index; HLA-B27, human leucocyte antigen B27; mSASSS modified Stoke Ankylosing Spondylitis Spinal Score, NSAID Nonsteroidal anti-inflammatory drug, TNFi Tumour necrosis factor inhibitor
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Arthritis Research & Therapy

ISSN: 1478-6362

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