Table 2

Associations between BASFI, SF-36 PCS and SF-36 MCS (dependent variables) and other outcome measures and clinical-demographic variables (univariate linear regression analyses)

BASFISF-36 PCSSF-36 MCS
B (95% CI)βR2p ValueB (95% CI)βR2p ValueB (95% CI)βR2p Value
BASFINANANANA−2.198 (−2.620 to −1.776)−0.5760.332<0.001−1.565 (−2.303 to −0.828)−0.2760.076<0.001
ASDAS0.861 (0.581 to 1.141)0.3840.148<0.001−3.383 (−4.445 to −2.321)−0.3960.157<0.001−1.695 (-3.397 to 0.007)−0.1340.0180.051
BASDAI0.562 (0.411 to 0.713)0.4500.203<0.001−2.249 (−2.817 to −1.680)−0.4720.223<0.001−1.796 (−2.723 to −0.869)−0.2540.064<0.001
CRP0.194 (−0.076 to 0.464)0.0970.0090.158−0.857 (−1.884 to 0.170)−0.1120.0130.1010.346 (−1.188 to 1.880)0.0310.0010.657
BASMI0.518 (0.368 to 0.668)0.4230.179<0.001−0.915 (−1.535 to −0.295)−0.1960.0380.004−0.515 (−1.452 to 0.421)−0.0740.0060.279
mSASSS0.387 (0.129 to 0.645)0.1990.0400.003−0.826 (−1.825 to 0.172)−0.1110.0120.1040.594 (−0.896 to 2.084)0.0540.0030.433
ASspiMRI-a0.120 (−0.153 to 0.393)0.0590.0040.3870.791 (−0.248 to 1.830)0.1020.0110.1350.769 (−0.779 to 2.317)0.0670.0050.328
Disease duration−0.043 (−0.347 to 0.178)−0.0840.0020.5280.050 (−0.953 to 1.052)0.0070.0010.9220.226 (−1.262 to 1.715)0.0210.0000.765
Age0.037 (0.012 to 0.063)0.1960.0380.004−0.140 (−0.237 to −0.043)−0.1920.0370.005−0.106 (−0.253 to 0.040)−0.0980.0100.152
Gender (male)−0.343 (−0.965 to 0.279)−0.0740.0060.2793.220 (0.880 to 5.559)0.1830.0340.0070.528 (−3.005 to 4.061)0.0200.0000.769
BMI0.119 (0.057 to 0.181)0.2530.064<0.001−0.191 (−0.433 to 0.050)−0.1070.0110.120−0.527 (−0.881 to −0.173)−0.1980.0390.004
HLA-B27+0.238 (−0.607 to 1.083)0.0380.0010.580−0.172 (−3.397 to 3.053)−0.0070.0010.916−1.976 (−6.756 to 2.805)−0.0560.0030.416
  • p Values <0.05 are highlighted in bold.

  • ASDAS, Ankylosing Spondylitis Disease Activity Score; ASspiMRI-a, Ankylosing Spondylitis spinal MRI activity; B, regression coefficient; β, standardised coefficient; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BASMI, linear definition of the Bath Ankylosing Spondylitis Metrology Index; BMI, Body Mass Index; CRP, C-reactive protein; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; R2, an estimate of the proportion of variance in the dependent variable accounted for by the regression; SF-36 PCS, SF-36 Physical Component Summary Score; SF-36 MCS, SF-36 Mental Component Summary Score; NA, not applicable.