Table 1: Characteristics data of patients.
| Variable | Mean values ± Std. deviation | Min. value | Max. value |
| Age | 69.3 ± 7.06 | 52.00 | 82.00 |
| Age of smoking initiation | 18.3 ± 9.8 | 0.00 | 60.00 |
| Cigarette/day | 28.3 ± 14.3 | 0.00 | 80.00 |
| Smoking years | 38.6 ± 14.8 | 0.00 | 60.00 |
| Age of smoking initiation | 59.3 ± 39.2 | 0.00 | 224.00 |
| Duration of cough (yrs) | 9.4 ± 5.8 | 2.00 | 30.00 |
| Duration of sputum (yrs) | 7.96 ± 5.52 | 1.00 | 30.00 |
| Duration of dyspnea (yrs.) | 7.2 ± 5.26 | 1.00 | 35.00 |
| Recuperative time (days) | 7.05 ± 1.86 | 5.00 | 12.00 |
| BMI index | 25.47 ± 5.09 | 16.50 | 48.40 |
| FVC (% predicted) | 56.89 ± 11.84 | 30.00 | 91.10 |
| FEV1 (% predicted) | 36.87 ± 8.57 | 20.00 | 50.00 |
| Tiffeneau Index (%) | 51.44 ± 9.18 | 25.40 | 67.10 |
| SaO2 | 90.34 ± 3.78 | 84.00 | 97.00 |
| CAT score | 26.54 ± 6.8 | 9.00 | 35.00 |
| MRC dyspnea scale | 3.52 ± 0.87 | 2.00 | 5.00 |
| Gender | Male | 54.00 (96.4%) | |
| Female | 2.00 (3.6%) | ||
| COPD GOLD stage | Stage III | 27.00 (48%) | |
| Stage IV | 29.00 (52%) | ||
| COPD GOLD category | C3 | 2.00 (3%) | |
| D3 | 43.00 (77%) | ||
| D4 | 11.00 (20%) | ||
| Exacerbation | Type I | 32.00 (57.2%) | |
| Type II | 12.00 (21.4%) | ||
| Type III | 12.00 (21.4%) | ||