Table 3–
Demographic and Clinical Characteristics at Enrollment*
| Characteristics | Resting PaO2> 60 mm Hg and Continuous Oxygen (n = 260) | Resting Pao2> 60 mm Hg and No Oxygen (n = 226) | p Value |
|---|---|---|---|
| Age, yr | 65.5 ± 6.4 | 66.7 ± 6.5 | 0.04 |
| Race | |||
| White | 247 (95) | 214 (95) | > 0.99 |
| Nonwhite | 13 (5) | 12 (5) | |
| Gender | |||
| Female | 101 (39) | 72 (32) | 0.13 |
| Male | 159 (61) | 154 (68) | |
| Pack-yr† | 63.9 ± 30.1 | 63.8 ± 33.4 | 0.97 |
| Income, $ | |||
| < 15,000 | 54 (21) | 40 (18) | 0.37 |
| 15,000–29,999 | 90 (35) | 76 (35) | |
| 30,000–49,000 | 76 (29) | 65 (29) | |
| ≥ 50,000 | 34 (13) | 41 (18) | |
| Missing/no answer | 6 (2) | 1 (0.5) | |
| BMI, kg/m2 | 25,1 ± 3.8 | 24.1 ± 3.2 | 0.002 |
| FEV1, L | 0.75 ± 0.22 | 0.89 ± 0.26 | < 0.0001 |
| FEV1, % predicted‡ | 25.8 ± 6.8 | 29.8 ± 7.4 | < 0.0001 |
| FVC, L | 2.5 ± 0.8 | 2.8 ± 0.8 | 0.0002 |
| FVC, % predicted‡ | 65.7 ± 14.7 | 70.9 + 15.0 | 0.0002 |
| TLC, L | 7.7 ± 1.6 | 7.8 ± 1.5 | 0.17 |
| TLC, % predicted§ | 127.5 ± 15.0 | 127.1 ± 13.6 | 0.72 |
| RV, L | 5.0 ± 1.2 | 4.9 + 1.1 | 0.23 |
| RV, % predicted§ | 226.1 ± 48.8 | 214.8 ± 42.9 | 0.002 |
| IC, L | 1.7 ± 0.6 | 1.9 ± 0.6 | < 0.0001 |
| IC, % predicted | 60.1 ± 17.3 | 66.8 ± 17.3 | < 0.0001 |
| Dlco, mL/min/mm Hg | 7.7 ± 3.5 | 9.9 ± 3.4 | 0.25 |
| Dlco, % predicted‖ | 27.8 ± 11.6 | 30.4 ± 6.6 | 0.64 |
| 6-min walk distance, feet | 1143 ± 292 | 1363 ± 305 | < 0.0001 |
| Maximum exercise, W | 37.1 ± 21.1 | 47.3 ± 22.8 | < 0.0001 |
| Exercise desaturation | |||
| Present | 210 (81) | 79 (35) | < 0.0001 |
| Absent | 50 (19) | 147 (65) | |
| UCSD-SOBQ¶ | 68.2 ± 17.8 | 55.6 ± 19.6 | < 0.0001 |
| QWB# | 0.55 ± 0.13 | 0.58 ± 0.10 | 0.008 |
| SGRQ** | |||
| Symptoms | 58.8 ± 20.4 | 56.0 ± 20.0 | 0.14 |
| Activity | 81.7 ± 12.8 | 75.0 ± 15.0 | < 0.0001 |
| Impact | 40.2 ± 16.5 | 34.4 ± 14.5 | < 0.0001 |
| Total | 55.9 ± 13.3 | 50.4 ± 12.5 | < 0.0001 |
| mBODE score†† | |||
| 0–2 | 5 (1.9) | 18 (8.0) | < 0.0001 |
| 3–4 | 67 (25.8) | 115(51.1) | |
| 5–6 | 112 (43.1) | 71 (31.6) | |
| 7–10 | 76 (29.2) | 21 (9.3) |
Values are given as mean ± SD or No. (%). TLC = total lung capacity; RV = residual volume; IC = inspiratory capacity; Dlco = diffusing capacity of the lung for carbon monoxide.
No. of cigarettes smoked daily on average/20 times total years smoked.
Predicted values calculated from Crapo et al.16
Predicted values calculated from Crapo et al.17
Predicted values calculated from Crapo Morris.18
The UCSD-SOBQ is a 24-item questionnaire regarding dyspnea. Scores range from 0 to 120 with higher scores indicating more dyspnea.
The QWB scale is a 77-item questionnaire focusing on generic health-related quality of life. Scores range from 0 to 1, with higher scores indicate better quality of life.
The SGRQ is a 51-item questionnaire focusing on respiratory symptoms and quality of life. Scores range from 0 to 100, with higher scores indicating worse health-related quality of life.
The mBODE is a composite 11-point score.