Table 3.
Differences in clinical characteristics between patients of smoking-cessation group and continuing-smoking group
| Parameter | Both groups | Quitting smoking | Continuing smoking | P-value |
|---|---|---|---|---|
| Subjects, n | 204 | 92 | 112 | |
| Sex (M/F), n | 201/3 | 90/2 | 111/1 | 0.452 |
| Age, years | 67.9±9.4 | 68.4±9.3 | 67.4±9.4 | 0.425 |
| Age of quitting smoking, years | 58.8±10.4 | |||
| Pack-year | 45.3±34.5 | 44.6±29.4 | 45.9±38.3 | 0.791 |
| Years of smoking, years | 38.2±11.5 | 35.5±10.8 | 41.6±11.6 | 0.001 |
| Cigarettes smoked in 1 day, n | 23.0±13.0 | 23.9±11.9 | 22.2±13.8 | 0.353 |
| Age of onset of smoking, years | 25.9±8.3 | 25.1±8.2 | 26.8±8.2 | 0.131 |
| Death | 113 | 40 | 73 | 0.002 |
| Exacerbations in past 12 months | 1.3±1.4 | 1.1±1.9 | 1.2±1.7 | 0.286 |
| Course of disease, years | 12.7±10.8 | 13.9±10.5 | 10.8±10.9 | 0.040 |
| Onset of symptoms, years | 55.6±12.5 | 54.4±10.8 | 57.5±10.9 | 0.043 |
| FVC% predicted | 71.5±19.4 | 73.1±19.7 | 70.2±19.1 | 0.290 |
| FEV1% predicted | 43.3±19.1 | 44.5±19.3 | 42.6±19.0 | 0.486 |
| FEV1/FVC | 46.7±11.3 | 46.8±10.5 | 46.6±12.0 | 0.895 |
| RV% predicted | 207.5±66.7 | 197.3±54.7 | 215.9±74.2 | 0.041 |
| RV/TLC | 66.0±10.8 | 65.1±10.0 | 66.8±11.5 | 0.272 |
| DLCO % predicted | 72.9±45.5 | 69.3±27.1 | 75.9±56.2 | 0.307 |
| R% predicted | 256.6±133.0 | 255.3±126.5 | 257.7±138.6 | 0.897 |
| PO2, mmHg | 81.1±23.7 | 81.2±24.3 | 81.1±23.3 | 0.983 |
| PCO2, mmHg | 45.0±14.2 | 44.8±13.3 | 45.2±14.9 | 0.812 |
Notes: Statistically significant values are shown in bold. Data shown as mean ± standard deviation.
Abbreviations: DLCO, single-breath diffusing capacity of carbon monoxide; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; PCO2, partial pressure of carbon dioxide; PO2, partial pressure of oxygen; R, airway resistance; RV, residual volume; TLC, total lung capacity.