Risk of admission to hospital for COPD by changes in smoking habits and lung function measurements in the Copenhagen City Heart Study
| CCHS (n=3640) | Omitting first 5 years | ||||
|---|---|---|---|---|---|
| No of events | Crude hazard ratio (95% CI)* | Adjusted hazard ratio (95% CI)† | No of events | Adjusted hazard ratio (95% CI)‡ | |
| Results from Cox’s proportional hazards regression analysis. | |||||
| *Adjusted for age and sex (total number of events = 397). | |||||
| †Multivariate analysis adjusted for age, sex, inhalation habits, FEV1 % predicted, and years of smoking (continuous). | |||||
| ‡Multivariate analysis and with exclusions of hospital admissions until 5 years after second examination. Total number of events = 285. | |||||
| §Mean FEV1 percent predicted: 103.7%, 85.4%, and 64.6%, respectively. | |||||
| Smoking category | |||||
| Heavy smokers | 324 | 1 | 1 | 241 | 1 |
| Quitters | 27 | 0.58 (0.39 to 0.86) | 0.65 (0.44 to 0.96) | 18 | 0.41 (0.23 to 0.72) |
| Light smokers | 14 | 0.36 (0.21 to 0.61) | 0.84 (0.47 to 1.51) | 13 | 1.07 (0.56 to 2.01) |
| Reducers | 32 | 1.11 (0.83 to 1.24) | 1.19 (0.82 to 1.71) | 13 | 0.95 (0.58 to 1.54) |
| Tertile of FEV1 (% predicted)§ | |||||
| High | 49 | 1 | 1 | 42 | 1 |
| Middle | 62 | 1.16 (0.80 to 1.69) | 1.01 (0.70 to 1.48) | 51 | 0.99 (0.66 to 1.50) |
| Low | 286 | 4.70 (3.47 to 6.37) | 3.98 (2.93 to 5.41) | 192 | 3.39 (2.42 to 4.75) |