Table 4

Final multivariate linear regression analyses of FSS on sociodemographic, clinical and self-reported health status variables

VariableβSEt Valuep ValueProportion of R2 explained uniquelyProportion of R2 explained individually*
Intercept7.830.6412.32<0.001
Sex (male vs female)−0.440.23−1.880.060.46%8.64%
SF-36 pain dimension−0.020.006−3.210.0011.34%36.38%
SF-36 mental health dimension−0.040.006−7.13<0.0016.59%29.67%
No of fibromyalgia tender points0.090.023.80<0.0011.87%23.08%
HAQ1.070.254.24<0.0012.33%37.79%
Methotrexate ever (yes vs no)0.590.222.660.0080.92%7.28%
Residual standard error1.98
Residual degrees of freedom351
Multiple R254.51%
Adjusted R253.73%
Overall unique variation explained13.51%
Overall shared variation explained41.00%
Overall unexplained variation45.49%
No of observations deleted due to missing data141
  • *The proportion of R2 explained individually differs from that in table 2 due to the deletion of 141 observations because of missing information. FSS, fatigue severity scale; HAQ, health assessment questionnaire; SF-36, medical outcome survey short form 36.