Table 3 Initial and final model of multiple linear regression analysis with backward selection
VariableMRI of wrist + MCP group (n = 89)MRI of wrist only group (n = 130)
CoefficientConfidence intervalp ValueCoefficientConfidence intervalp Value
All explanatory variables in the model
Gender−0.73−3.31 to 1.850.57−0.24−2.14 to 1.660.80
Age0.03−0.87 to 0.930.510.04−0.04 to 0.110.34
DAS28−0.65−1.47 to 0.170.12−0.51−1.23 to 0.220.17
Ever smoker−0.16−3.38 to 3.060.92−0.43−3.17 to 2.320.76
Anti-CCP3.00−0.39 to 6.380.082.94−0.10 to 5.980.06
Ever smoker and anti-CCP−2.26−6.54 to 2.020.30−1.93−5.65 to 1.790.30
HLA-DRB1-SE0.12−2.41 to 2.660.920.47−1.75 to 2.690.67
MRI erosion score0.19−0.42 to 0.790.54−0.05−0.63 to 0.530.86
MRI synovitis score0.20−0.09 to 0.480.170.08−0.33 to 0.500.69
MRI bone oedema score0.660.40 to 0.92<0.0010.570.32 to 0.82<0.001
TSS0.05−0.14 to 0.250.570.09−0.05 to 0.220.19
Only significant variables in the model
MRI bone marrow oedema score0.750.55 to 0.94<0.0010.590.40 to 0.77<0.001
  • CCP, cyclic citrullinated peptide (dichotomised value); DAS28, Disease Activity Score (28-joint count); MCP, metacarpophalangeal; MRI, magnetic resonance imaging; SE, shared epitope; TSS, Total Sharp Score.