Patients’ characteristics
| Variable | Mean±SD (range) |
| Total number of patients | 65 |
| Age, years | 71.9±8.4 (46–89) |
| Sex, male/female | 65/0 |
| Height, cm | 164.6±6.3 (145.3–178) |
| Weight, kg | 60.5±9.4 (41.5–88) |
| BMI, kg/m2 | 22.3±3.0 (16–31.6) |
| Smoking status, former/current | 60/5 |
| Smoking history, pack-years | 63.2±32.4 (18–184) |
| FSSG score | 6.1±6.04 (0–36) |
| GER symptoms (FSSG ≥8) | 20/45 |
| CAT | 11.28±6.97 (1–28) |
| mMRC Dyspnoea Scale, 0/1/2/3/4 | 21/28/13/2 |
| GOLD stage, I/II/III/IV | 10/34/14/7 |
| FEV1, L | 1.63±0.6 (0.62–2.91) |
| FEV1, % predicted | 58.87±19.74 (17.7–96.9) |
| FVC, L | 3.2±0.8 (1.76–4.99) |
| FEV1/FVC, % | 49.94±13.5 (0.23–100) |
| VC, L | 3.5±0.7 (2.01–4.95) |
| VC, % predicted | 99.61±16 (63–131.7) |
| IC/TLC, % | 37.84±6.63 (24.24–52.91) |
| RV/TLC, % | 40.9±7.5 (27–67) |
| DLco, mL/min/mm Hg | 13.32±5.41 (3.6–28.27) |
The continuous variables are presented as the mean±SD (range).
BMI, body mass index; CAT, Chronic Obstructive Pulmonary Disease Assessment Test; DLco, diffusing capacity of carbon monoxide; FEV1, forced expiratory volume in 1 s; FSSG, frequency scale for symptoms of gastro-oesophageal reflux disease; FVC, forced vital capacity; GER, gastro-oesophageal reflux; GOLD, Global Initiative for Chronic Obstructive Lung Disease; IC, inspiratory capacity; mMRC, modified Medical Research Council; RV, residual volume; TLC, total lung capacity; VC, vital capacity.