Table 2.

Regression coefficients based on a random effects model

Level	Physiological variables		Symptom status	Functional status	Health perceptions	Health related quality of life
Model	I MRC	II FVC	III FSS	IV RHS	V EQ-5D VAS	VI MCS	VII PCS	VIII Utility
Constant	83.452	70.526	8.737	16.989	−9.313	49.990	24.526	0.530
Age	−0.069	−0.144	0.011	−0.096	0.126	−0.016	−0.046	0.001
Female	−0.028	17.994	0.307	−0.957	4.673	−1.282	−0.402	0.010
Disease duration	−0.563	−0.346	−0.077	−0.052	0.653	0.063	−0.086	−0.001
Enzyme activity	0.370	−0.431	0.007	−0.048	0.004	−0.359	−0.069	−0.006
Muscle strength			−0.031	0.189
Respiratory function			−0.011	0.075
Fatigue Severity Scale				−0.578
Rotterdam Handicap Scale					2.030
Visual Analogue Scale						0.157	0.223	0.004
patients	78	72	61	61	73	73	73	71
observations	249	257	160	158	154	152	152	161
R2 (overall)	0.105	0.075	0.322	0.623	0.343	0.183	0.293	0.354
Wald test (p-value)	<0.001	0.001	0.002	<0.001	<0.001	0.005	<0.001	<0.001

Figures in bold indicate significance at 5 % level; Enzyme activity, muscle strength and respiratory function were measured as a percentage of normal values, Visual Analogue Scale, Mental Component Scale and Physical Component Scale were measured on a scale from 0–100, Fatigue Severity Scale was measured on a scale from 1–7, Rotterdam Handicap Scale was measured on a scale from 0–36, Utility was measured on a scale from 0–1