Multivariate linear regression models exploring the independent association between SF-36 PCS (dependent variable) and other clinical and demographic variables
| SF-36 PCS (model 1) | SF-36 PCS (model 2) | SF-36 PCS (model 3) | SF-36 PCS (model 4) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| B (95% CI) | β | p Value | B (95% CI) | β | p Value | B (95% CI) | β | p Value | B (95% CI) | β | p Value | |
| BASFI | −1.739 (−2.210 to −1.268) | −0.456 | <0.001 | −1.652 (−2.126 to −1.179) | −0.433 | <0.001 | ||||||
| BASMI | −0.715 (−1.295 to −0.136) | −0.153 | 0.016 | −0.945 (−1.502 to −0.388) | −0.202 | 0.001 | ||||||
| ASDAS | −2.046 (−3.051 to −1.041) | −0.240 | <0.001 | −3.487 (−4.497 to −2.476) | −0.408 | <0.001 | ||||||
| BASDAI | −1.309 (−1.877 to −0.741) | −0.275 | <0.001 | −2.209 (−2.755 to −1.663) | −0.464 | <0.001 | ||||||
| Disease duration | 0.271 (−0.601 to 1.143) | 0.037 | 0.540 | −0.019 (−0.878 to 0.840) | −0.003 | 0.965 | 1.049 (0.083 to 2.015) | 0.142 | 0.033 | 0.591 (−0.348 to 1.530) | 0.080 | 0.216 |
| Age | −0.092 (−0.183 to −0.001) | −0.126 | 0.049 | −0.085 (−0.175 to 0.004) | −0.117 | 0.062 | −0.148 (−0.247 to −0.049) | −0.203 | 0.004 | −0.127 (−0.222 to −0.031) | −0.173 | 0.010 |
| BMI | 0.063 (−0.141 to 0.267) | 0.035 | 0.545 | 0.082 (−0.119 to 0.283) | 0.046 | 0.424 | −0.101 (−0.320 to 0.119) | −0.056 | 0.367 | −0.049 (−0.262 to 0.163) | −0.027 | 0.649 |
| Gender (male) | 2.572 (0.679 to 4.464) | 0.146 | 0.008 | 1.926 (0.054 to 3.799) | 0.110 | 0.044 | 3.451 (1.357 to 5.546) | 0.196 | 0.001 | 2.415 (0.381 to 4.448) | 0.137 | 0.020 |
| R2=0.41 | R2=0.42 | R2=0.27 | R2=0.32 | |||||||||
| adjR2=0.39 | adjR2=0.40 | adjR2=0.25 | adjR2=0.30 | |||||||||
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; BMI, Body Mass Index; 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.