Baseline characteristics by disease severity
Subjects n | Disease severity | p-value | |||
Mild (MRC grade 1/2)# | Moderate (MRC grade 2/3)¶ | Severe (MRC grade 5)+ | |||
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 |
Sa,O2 pre-6MWD % | 73 | 95.9±2.1 | 93.8±3.0 | 92.5±3.3 | 0.001 |
Sa,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; Sa,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.