Table 1.
Characteristics of the Study Population
| Characteristic | Analysis (N = 1,564) |
|---|---|
| Age, y | 68 (62-74) |
| Male | 841 (54%) |
| Black | 281 (18%) |
| Education | |
| High school, no diploma | 117 (7%) |
| High school graduate or GED | 379 (24%) |
| Some college or technical school, no degree | 467 (30%) |
| College or technical school graduate (bachelor's or associate degree) | 437 (28%) |
| Master's or doctoral degree | 164 (10%) |
| BMI, kg/m2 | 28 (24-31) |
| Obese (BMI ≥ 30 kg/m2) | 519 (33%) |
| Anemia | 197 (13%) |
| Diabetes | 249 (16%) |
| Congestive heart failure | 60 (4%) |
| Sleep apnea | 280 (18%) |
| Pack-years of smoking | 45 (34-63) |
| Smoking status | |
| Former smoker | 484 (31%) |
| Current-to-former smokera | 191 (12%) |
| Current smoker | 889 (57%) |
| FEV1 % predicted | 70 (51-89) |
| ≤ 50% | 378 (24%) |
| Dlco % predicted | 66 (50-82) |
| ≤ 50% | 388 (25%) |
| KCO % predicted | 73 (58-87) |
| ≤ 50% | 246 (16%) |
| CAT | 13 (7-20) |
| SGRQ | 28 (13-45) |
| SF-36 Physical Function | 42 (33-50) |
| SF-36 Mental | 55 (46-60) |
| 6MWD, feet | 1,280 (1,000-1,512) |
| %LAA-950 | 4 (1-14) |
| LAA-950 > 5% | 741 (47%) |
| Resting Spo2, % | 96 (94-97) |
Data are expressed as median (interquartile range) or No. (%) as appropriate. 6MWD = 6-min walk distance; CAT = COPD Assessment Test; Dlco = diffusing capacity of the lung for carbon monoxide; GED = General Education Diploma; KCO = gas transfer efficiency coefficient; %LAA-950 = percent low attenuation areas at or below –950 Hounsfield units consistent with emphysema; SF-36 = Medical Outcomes Study Short Form 36; SGRQ = St. George’s Respiratory Questionnaire; Spo2= oxygen saturation.
a
Participants who went from being current smokers at the phase I visit to former smokers by the phase II visit.