Table 5.
Associations of symptoms and disease histories with cluster membership
| Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | P value | |
|---|---|---|---|---|---|
| N = 100 | N = 80 | N = 141 | N = 85 | ||
| Symptoms and disease History | |||||
| Smoking pack-years at baseline |
48.09 (22.27) |
48.21 (25.3) |
57.64 (27.4) |
54.44 (22.9) |
0.001 |
| History of pulmonary/vascular condition (%) | 24 | 18 | 21 | 39 | 0.0056 |
| Chronic Bronchitis (%) | 10 | 18 | 19 | 31 | 0.005 |
| Emphysema (%) | 28 | 24 | 45 | 76 | < 0.0001 |
| COPD diagnosed at baseline (%) | 40 | 34 | 64 | 88 | < 0.0001 |
| Chronic bronchitis diagnosed at baseline (%) | 11 | 5 | 16 | 19 | 0.061 |
| Asthma (%) | 12 | 20 | 19 | 23 | 0.285 |
| Wheezing and whistling in chest (%) | 46 | 50 | 59 | 59 | 0.167 |
| Wheezing age (yrs.) (%) | 60 | 67 | 78 | 68 | 0.19 |
| Sleep Apnea at baseline (%) | 28 | 29 | 15 | 17 | 0.106 |
| Shortness of breath during sleep (%) | 6 | 17 | 7 | 17 | 0.012 |
| Coronary artery disease | 6 | 12 | 15 | 7 | 0.101 |
| Diabetes (%) | 12 | 19 | 11 | 14 | 0.452 |
| Heart attack (%) | 1 | 5 | 6 | 10 | 0.08 |
| Congestive heart failure (%) | 1 | 2 | 3 | 2 | 0.81 |
| Genetic effect | |||||
| Father had COPD (%) | 15 | 14 | 22 | 33 | 0.006 |
| Mother had COPD (%) | 9 | 12 | 12 | 23 | 0.041 |