Baseline characteristics of patients in the cohort
| Variables | Male | Female | p-value# |
| Subjects n | 272 | 265 | |
| Age yrs | 67±8 | 63±10 | <0.001 |
| Current smoking % | 32 | 44 | 0.005 |
| Tobacco use pack·yr−1 | 81±43 | 51±29 | <0.001 |
| Charlson's index points | 3.8±2.6 | 2.7±2.4 | <0.001 |
| BODE index points | 3.49±2.5 | 3.37±2.1 | 0.55 |
| MMRC points | 2.0±1.1 | 2.11±0.9 | 0.5 |
| 6MWD m | 392±138 | 392±103 | 0.9 |
| BMI kg·m−2 | 26.8±5 | 25.7±5 | <0.01 |
| FEV1 % pred | 49±20 | 50±19 | 0.87 |
| FVC % pred | 74±22 | 78.7±23 | 0.05 |
| FEV1/FVC % | 46±13 | 48.8±12 | 0.06 |
| IC/TLC % | 32±1 | 30±1 | 0.05 |
| SGRQ total | 44±21 | 48±19 | 0.04 |
Data are presented as mean±sd, unless otherwise stated. BODE: body mass index (BMI), airflow obstruction, dyspnoea, exercise capacity; MMRC: modified Medical Research Council dyspnoea scale; 6MWD: 6-min walk distance; FEV1: forced expiratory volume in one second; % pred: % predicted; FVC: forced vital capacity; IC: inspiratory capacity; TLC: total lung capacity; SGRQ: St George's Respiratory Questionnaire. #: comparison between males and females.