Table 1—

Baseline characteristics by disease severity

	Subjects n	Disease severity			p-value
	Subjects n	Mild (MRC grade 1/2)^#	Moderate (MRC grade 2/3)^¶	Severe (MRC grade 5)⁺	p-value
Age yrs	74	63.6±11.4	67.9±9.6	73.2±7.9	0.005
BMI kg·m⁻²^§	74	26.3±5.2	29.2±8.7	25.8±5.5	ns
Smoking pack-yrs^§	73	38.1±28.0	48.8±39.3	51.7±30.9	ns
6MWD % pred	73	71.3±14.2	50.2±18.2	27.7±15.8	<0.0001
Quadriceps torque (Nms/kg×100)	74	123.5±35.5	123.0±55.0	83.9±36.8	0.003
SGRQ score^§	74	38.0±14.8	61.2±12.9	65.5±14.2	<0.0001
FEV₁ % pred	73	65.7±20.0	43.0±24.4	38.1±16.9	<0.0001
FVC % pred	73	83.7±20.7	65.6±19.7	66.4±23.8	0.008
MIP % pred	66	74.4±35.8	72.2±31.6	59.4±19.3	ns
MEP % pred	66	98.2±44.0	87.9±32.1	77.4±34.6	ns
V′_O₂,max kg·L⁻¹·min⁻¹	71	16.2±7.0	10.9±6.0	7.1±1.9	<0.0001
Grip % pred	74	109.9±17.6	102.6±24.0	99.3±25.1	ns
Borg score pre-6MWD m^§	72	0.2±0.3	0.7±0.7	1.0±1.1	0.009
Borg score post-6MWD m^§	72	3.1±1.4	3.7±0.9	4.5±1.5	0.002
S_a,O₂ pre-6MWD %	73	95.9±2.1	93.8±3.0	92.5±3.3	0.001
S_a,O₂ post-6MWD %	73	94.5±3.8	91.0±6.2	88.5±6.2	0.003
COPDSE	72	3.4±1.0	2.9±0.9	2.7±0.9	0.03
LCADL^§	74	19.3±10.4	33.6±14.3	46.2±16.4	<0.0001

Differences were tested using ANOVA. Data are presented as mean (sd). A high score indicates better health, unless otherwise indicated (^§: low score = better health). MRC: Medical Research Council; BMI: body mass index; 6MWD: 6-minute walk distance; SGRQ: St George's Respiratory Questionnaire; FEV₁: forced expiratory volume in one second; % pred: per cent predicted; FVC: forced vital capacity; MIP: maximal inspiratory pressure; MEP: maximal expiratory pressure; V′_O₂,max: maximal oxygen consumption; S_a,O₂: arterial oxygen saturation; COPDSE: Chronic Obstructive Pulmonary Disease Self-Efficacy Scale; LCADL: London Chest Activity of Daily Living Scale. ^#: n = 21; ^¶: n = 29; ⁺: n = 24; ns: nonsignificant.