Baseline characteristics of frequent and infrequent exacerbators
| Frequent exacerbators | Infrequent exacerbators | p-value | |
| Subjects n | 61 | 106 | |
| Age yrs | 70.7±8.5 | 71.1±8.5 | 0.77 |
| Time outdoors h | 3.4±1.9 | 3.5±2.5 | 0.90 |
| FEV1 | |||
| L | 1.0±0.4 | 1.2±0.5 | 0.005 |
| % pred | 41.7±15.3 | 49.7±20.0 | 0.005 |
| FVC L | 2.2±0.8 | 2.53±0.9 | 0.03 |
| BMI kg·m−2 | 25.9±4.7 | 26.5±6.0 | 0.50 |
| Smoking history pack-yrs | 49.2±28.3 | 48.4±36.1 | 0.89 |
| SGRQ | |||
| Total | 59.8±14.5 | 46.0±17.2 | <0.001 |
| Activity | 75.9±16.4 | 62.3±23.2 | <0.001 |
| Impact | 46.7±18.0 | 33.2±17.3 | <0.001 |
| Symptoms | 71.9±15.2 | 56.6±20.4 | <0.001 |
| MRC dyspnoea score | 3.2±0.9 | 2.8±1.2 | 0.016 |
| Depression score | 17.7±12.4 | 13.6±10.0 | 0.03 |
Data are presented as mean±sd. FEV1: forced expiratory volume in one second; % pred: % predicted; FVC: forced vital capacity; BMI: body mass index; SGRQ: St George Respiratory Questionnaire; MRC: Medical Research Council.