Table 4

Univariable and multivariable linear regression analysis with CSI as dependent variable with patient and disease characteristics, psychosocial assessments and QST (n=201)

UnivariableMultivariable
R2B95% CIBStandardised ß95% CI
Age, years0.02−0.16*−0.31, to 0.00
Sex, male vs female0.1310.88*6.89, 14.868.36*0.275.98, 10.73
Diagnostic delay, years0.000.03−0.25, 0.31
BMI, kg/m20.000.16−0.20,0.51
CRP, mg/L0.00−0.02−0.37, 0.33
ASDAS0.257.56*5.71, 9.41
BASDAI0.444.46*3.75, 5.16
ASQoL, 0–180.502.20*1.87, 2.54
BASFI, 0–100.263.26*2.42, 4.09
mSQUASH total activity score0.05−0.01*−0.01, 0.00
Psychosocial assessments
IPQ-R identity, 0–140.423.82*3.18, 4.461.78*0.281.19, 2.37
IPQ-R timeline acute/chronic, 6–300.000.29−0.19, 0.94
IPQ-R timeline cyclical, 4–200.030.28*0.16, 1.27
IPQ-R personal control, 6–300.030.25*−1.12, to 0.14
IPW-R treatment control, 6–300.080.32*−1.94, to 0.68
IPQ-R illness coherence, 5–250.090.24*−1.49, to 0.56
IPQ-R consequences, 6–300.251.37*1.03, 1.71
IPQ-R emotional representations, 6–300.242.05*1.54, 2.57
PCS, 0–520.380.95*0.78, 1.120.28*0.170.12, 0.44
MFIS, 0–840.610.04*0.61, 0.760.29*0.320.19, 0.39
HADS anxiety, 0–210.352.70*2.18, 3.220.99*0.230.54, 1.45
HADS depression, 0–210.180.26*1.18, 2.20
CORS pain comforting cognitions, 9–360.010.22−0.76, 0.12
CORS pain decreasing activities, 8–310.170.21*0.90, 1.74
CORS pain diverting attention, 8–300.000.23−0.25, 0.66
CORS limitations optimism, 5–200.050.33*−1.64 to to 0.35
CORS limitations pacing, 10–400.010.15−0.08, 0.52
CORS limitations creative solution seeking, 8–320.000.20−0.28, 0.51
CORS dependence acceptance, 6–240.020.22−0.86, 0.00
CORS dependence showing consideration, 7–280.000.28−0.47, 0.63
QST measurements
PPT sum values, N
With most painful area0.09−0.24*−0.35, 0.14
Without most painful area0.09−0.24*−0.35, 0.13
TS non-dominant forearm, N0.042.55*0.77, 4.32
CPM non-dominant m. rectus femoris, N0.00−0.02−0.19, 0.16
  • Order of inclusion CSI: (1) MFIS (R2=0.60); (2) IPQ-R Identity (R2=0.66); (3) Sex (R2=0.71);(4) HADS anxiety (R2=0.76); (5) PCS (R2=0.78).

  • *p<0.05.

  • ASDAS, Axial Spondyloarthritis Disease Activity Score; ASQoL, Ankylosing Spondylitis Quality of Life questionnaire; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BMI, body mass index; CORS, Coping with Rheumatic Stressors questionnaire; CPM, conditioned pain modulation; CRP, C reactive protein; CSI, Central Sensitisation Inventory; HADS, Hospital Anxiety and Depression Scale; IPQ-R, Revised Illness Perception Questionnaire; MFIS, Modified Fatigue Impact Scale; mSQUASH, modified-Short Questionnaire to Assess Health-enhancing physical activity; PCS, Pain Catastrophising Scale; PPT, pain pressure threshold; QST, quantitative sensory testing; TS, temporal summation.