Table 1—

Baseline characteristics of the study population

AllCompleting studyLost to follow-up
Subjects n49145041
Age yrs65.7±10.765.2±10.670.7±10.10.002
Male sex338 (68.8)309 (68.7)29 (70.7)0.78
BMI kg·m−223.9±4.224.0±4.223.0±4.00.15
Cumulative smoking pack-yrs26.8±29.226.5±29.031.0±31.60.33
MRC dyspnoea grade ≥4123 (25.0)103 (22.9)20 (48.8)0.001
6MWD m384.6±135.9392.4±132.7287.2±141.00.0002
Spirometry (post-BD)
 FEV1 L1.16±0.471.18±0.470.96±0.360.005
 FEV1 % pred47.6±15.947.2±15.840.9±16.50.009
 FVC L2.35±0.802.37±0.792.07±0.790.02
 FVC % pred75.8±19.676.5±19.267.8±22.30.02
GOLD stage (FEV1)
 II (50–79% pred)211 (42.9)199 (44.2)12 (29.3)0.02
 III (30–49% pred)204 (41.6)188 (41.8)16 (39.0)
 IV (<30% pred)76 (15.5)63 (14.0)13 (31.7)
SGRQ score
  • Data are presented as mean±sd or n (%), unless otherwise indicated. BMI: body mass index; MRC: UK Medical Research Council; 6MWD: 6-min walking distance; BD: bronchodilator; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; SGRQ: St George's Respiratory Questionnaire. #: using unpaired two-tailed t-test for comparison of continuous variables (two means) and Chi-squared test for comparison of categorical variables (two proportions) between patients who completed the study and those lost to follow-up; : analyses were conducted amongst patients who had complete baseline data for 6MWD.