Table 1. Clinical parameters included in the analysis.
| Domain | Parameters |
|---|---|
| Baseline characteristics | Age, sex, weight, height, BMI, smoking status (never/former/active), smoking history (pack-years) |
| Symptoms | Cough with sputum production for 3 months/year during ≥2 consecutive years (yes/no) |
| BDI score (scale 0–12) | |
| Lung function | % predicted value: FEV1, FVC, IC, TLC, FRC, RV, D lco |
| Ratio: FEV1/FVC, IC/TLC, RV/TLC | |
| Lower limit of normal status: FEV1/FVC (over/under) | |
| Peak exercise response | V′o2 peak (mL•kg-1•min-1), V′e peak (L•min-1), V′e peak/MVV, Vt (% predicted VC), Bf, V′e/V′o2, V′e/V′co2, dyspnea peak (Borg score; scale 0–10), leg fatigue peak (Borg score; scale 0–10), limiting factor (dyspnea/leg fatigue/both/other) |
| Levels of physical activity | Steps per day, daily energy expenditure >3 METs (kcal), daily time >3 METs (min) |
BMI: body mass index; BDI: Baseline Dyspnea Index; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; IC: inspiratory capacity; TLC: total lung capacity; FRC: functional residual capacity; RV: residual volume; D lco: diffusion capacity; V′o2: oxygen uptake; V′e: minute ventilation; MVV: maximal voluntary ventilation by multiplying FEV1 by 35; Vt: tidal volume; VC: vital capacity; Bf: breathing frequency; V′co2: carbon dioxide output; METs: metabolic equivalents.