Table 1.
Baseline Characteristics
| Variable | SGRQ CB– |
SGRQ CB+ |
P Value | Classic CB– |
Classic CB+ |
P Value |
|---|---|---|---|---|---|---|
| (n = 5,267) | (n = 2,290) | (n = 6,123) | (n = 1,434) | |||
| Race, non-Hispanic white, % | 71.8 | 76.5 | < .0001 | 72.2 | 77.5 | < .0001 |
| Sex, male, % | 50.3 | 57.4 | < .0001 | 51.1 | 58.5 | < .0001 |
| BMI, kg/m2 | 28.5 ± 5.9 | 28.5 ± 6.3 | .510 | 28.52 ± 5.94 | 28.46 ± 6.27 | .713 |
| Age, y | 60.86 ± 9.10 | 60.73 ± 8.80 | .548 | 60.93 ± 9.09 | 60.36 ± 8.65 | .030 |
| Smoking history, pack-years | 42.40 ± 23.58 | 50.30 ± 27.46 | < .0001 | 43.27 ± 24.24 | 51.34 ± 27.52 | < .0001 |
| Current smoking, % | 40 | 59.3 | < .0001 | 42 | 62.6 | < .0001 |
| FEV1% pred | 80.26 ± 25.94 | 67.15 ± 27.22 | < .0001 | 78.66 ± 26.52 | 66.09 ± 26.76 | < .0001 |
| FVC% pred | 90.57 ± 17.26 | 84.44 ± 19.31 | < .0001 | 89.69 ± 17.73 | 84.52 ± 19.18 | < .0001 |
| FEV1/FVC | 0.67 ± 0.16 | 0.59 ± 0.17 | < .0001 | 0.66 ± 0.16 | 0.59 ± 0.17 | < .0001 |
| 6-Min walk distance, ft | 1,412 ± 392 | 1,273 ± 397 | < .0001 | 1,395 ± 397 | 1,263 ± 387 | < .0001 |
| mMRC dyspnea score | 1.07 ± 1.34 | 1.94 ± 1.47 | < .0001 | 1.16 ± 1.38 | 2.06 ± 1.45 | < .0001 |
| Noct awake cough, % | 14.9 | 46 | < .0001 | 18.2 | 50.4 | < .0001 |
| Noct awake SOB, % | 13.7 | 33.7 | < .0001 | 15.4 | 38.4 | < .0001 |
| Allergic nasal sympt, % | 42.1 | 64.4 | < .0001 | 44.4 | 67.7 | < .0001 |
| Allergic ocular sympt, % | 37 | 51.6 | < .0001 | 38.3 | 54.6 | < .0001 |
| Dusty job ever, % | 42.2 | 54.6 | < .0001 | 43 | 58.6 | < .0001 |
| Fumes job ever, % | 43.9 | 54.7 | < .0001 | 44.4 | 59.1 | < .0001 |
| Exac freq, No./pt/y | 0.27 ± 0.75 | 0.72 ± 1.27 | < .0001 | 0.32 ± 0.83 | 0.79 ± 1.33 | < .0001 |
| History of severe exac, % | 8.3 | 19.2 | < .0001 | 9.7 | 20 | < .0001 |
| % Emphysema | 6.70 ± 9.94 | 8.44 ± 10.75 | < .0001 | 6.93 ± 10.07 | 8.50 ± 10.75 | < .0001 |
| % Gas trapping | 22.62 ± 20.06 | 28.76 ± 21.75 | < .0001 | 23.46 ± 20.48 | 28.87 ± 21.49 | < .0001 |
| Inhaled medications | ||||||
| LAMA, % | 4.3 | 7.3 | < .0001 | 4.7 | 7.6 | < .0001 |
| LABA, % | 0.5 | 1.2 | .002 | 0.6 | 1.3 | .013 |
| ICS, % | 2.6 | 4.7 | < .0001 | 2.8 | 5.3 | < .0001 |
| ICS + LABA, % | 8.2 | 14.2 | < .0001 | 8.6 | 15.9 | < .0001 |
| ICS + LAMA, % | 0.8 | 1.5 | .003 | 0.8 | 1.9 | .001 |
| LABA + LAMA, % | 0.6 | 1.5 | < .0001 | 0.8 | 1.2 | .110 |
| ICS + LABA + LAMA, % | 10.7 | 19.4 | < .0001 | 11.8 | 19.9 | < .0001 |
| Comorbidities | ||||||
| Cancer, % | 5.6 | 5.6 | 1.000 | 5.5 | 5.7 | .798 |
| Congestive heart failure, % | 2.5 | 3.9 | .001 | 2.7 | 3.9 | .019 |
| Coronary artery disease, % | 6.8 | 7.8 | .132 | 6.8 | 8.3 | .060 |
| Diabetes, % | 11.5 | 13.1 | .045 | 11.9 | 12.1 | .892 |
| Hypertension, % | 42.0 | 45.6 | .004 | 42.5 | 45.3 | .054 |
| Cerebrovascular disease, % | 2.3 | 3.1 | .055 | 2.5 | 2.4 | .925 |
| GERD, % | 25 | 31.7 | < .0001 | 24.4 | 30.4 | < .0001 |
Values are expressed as mean ± SD or percent. Medications are mutually exclusive groups. Probability values in boldface indicate significance. CB = chronic bronchitis; Exac freq = exacerbation frequency; GERD = gastroesophageal reflux disease; ICS = inhaled corticosteroids; LABA = long-acting β-agonist; LAMA = long-acting muscarinic antagonist; mMRC = modified Medical Research Council; Noct = nocturnal; SGRQ = St. George’s Respiratory Questionnaire; SOB = shortness of breath; sympt = symptoms.