Table 3

Multivariate linear regression models exploring the independent association between BASFI (dependent variable) and other clinical and demographic variables

BASFI (model 1)BASFI (model 2)BASFI (model 3)BASFI (model 4)
B (95% CI)βp ValueB (95% CI)βp ValueB (95% CI)βp ValueB (95% CI)βp Value
ASDAS0.812 (0.573 to 1.051)0.363<0.0010.884 (0.621 to 1.147)0.395<0.001
BASDAI0.545 (0.418 to 0.671)0.436<0.0010.570 (0.427 to 0.712)0.456<0.001
BASMI0.489 (0.352 to 0.626)0.399<0.0010.542 (0.413 to 0.671)0.443<0.001
mSASSS0.270 (0.002 to 0.538)0.1390.0480.464 (0.206 to 0.723)0.239<0.001
Disease duration−0.472 (−0.700 to −0.243)−0.243<0.001−0.360 (−0.578 to −0.141)−0.1850.001−0.354 (−0.604 to −0.104)−0.1830.006−0.244 (−0.487 to −0.002)−0.1260.048
Age0.031 (0.007 to 0.054)0.1600.0110.026 (0.004 to 0.048)0.1340.0230.032 (0.005 to 0.060)0.1680.0220.021 (−0.006 to 0.047)0.1090.121
BMI0.093 (0.040 to 0.144)0.1970.0010.080 (0.030 to 0.129)0.1700.0020.097 (0.040 to 0.154)0.2060.0010.082 (0.027 to 0.137)0.1740.004
Gender (male)−0.535 (−1.031 to −0.144)−0.1160.034−0.283 (−0.756 to 0.189)−0.0620.239−0.537 (−1.111 to 0.037)−0.1170.067−0.385 (−0.940 to 0.171)−0.0830.174
R2=0.40R2=0.47R2=0.28R2=0.33
adjR2=0.39adjR2=0.45adjR2=0.26adjR2=0.31
  • p Values <0.05 are highlighted in bold.

  • adjR2, adjusted R2, a better estimate of the population value of R2; ASDAS, Ankylosing Spondylitis Disease Activity Score; 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; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; R2, an estimate of the proportion of variance in the dependent variable accounted for by the regression.