N
|
591
|
292
|
299
| |
Age (year)
|
66.6 ± 5.3
|
66.9 ± 5.2
|
66.4 ± 5.3
|
0.208
|
Sex (female)
|
209 (35.4%)
|
93 (31.8%)
|
116 (38.8%)
|
0.074
|
Race (not white)
|
33 (5.6%)
|
20 (6.8%)
|
13.0 (4.3%)
|
0.185
|
Annual income < 30000 $
|
304 (51.4%)
|
155 (53.1%)
|
149 (49.8%)
|
0.429
|
FEV1 (%predicted)
|
26.7 ± 7.1
|
26.8 ± 7.1
|
26.7 ± 7.0
|
0.780
|
FEV1 (mL)
|
777 ± 240
|
782 ± 237
|
772 ± 243
|
0.456
|
FEV1/FVC (%)
|
31.2 ± 6.3
|
30.9 ± 6.0
|
31.5 ± 6.6
|
0.358
|
FVC (%predicted)
|
67.2 ± 15.1
|
68.0 ± 15.3
|
66.5 ± 14.9
|
0.346
|
FVC (mL)
|
2545 ± 782
|
2582 ± 772
|
2509 ± 791
|
0.225
|
Forced residual capacity (mL)
|
6042 ± 1311
|
6111 ± 1323
|
5975 ± 1298
|
0.243
|
Hb adjusted DLCO
|
8.1 ± 3.1
|
8.1 ± 3.0
|
8.0 ± 3.1
|
0.761
|
Peak pulmonary arterial pressure (mmHg)
|
33.7 ± 6.2 (N = 502)
|
34.2 ± 6.1 (N = 252)
|
33.3 ± 6.3 (N = 250)
|
0.110
|
Hemoglobin (g/dL)
|
14.4 ±1.3
|
14.4 ± 1.2
|
14.3 ± 1.3
|
0.905
|
PaO2 (mmHg)
|
64.2 ± 10.0
|
64.0 ±10.0
|
64.4 ± 10.0
|
0.838
|
PaCO2 (mmHg)
|
43.1 ± 5.8
|
43.6 ± 6.1
|
42.6 ± 5.4
|
0.083
|
Area of emphysema (%)
|
16.1 ± 10.6 (N = 532)
|
15.7 ± 11.1 (N = 259)
|
16.4 ± 10.2 (N = 273)
|
0.228
|
Body mass index (kg/m^2)
|
24.7 ± 3.5
|
24.7 ± 3.6
|
24.8 ± 3.5
|
0.503
|
Six-minute walk distance
|
368 ± 96
|
366 ± 95
|
370 ± 98
|
0.562
|
St. George respiratory questionnaire
|
53.6 ± 12.7
|
54.1 ± 12.6
|
53.1 ± 12.7
|
0.394
|
Shortness of breath questionnaire
|
63.3 ± 18.5
|
63.8 ± 18.1
|
62.7 ± 18.9
|
0.483
|
Beck depression inventory
|
9.3 ± 5.9
|
9.2 ± 5.8
|
9.3 ± 5.9
|
0.650
|
Recent emergency visit
|
75 (12.7%)
|
38 (13.0%)
|
37 (12.4%)
|
0.816
|
Recent hospital stay
|
48 (8.1%)
|
26 (8.9%)
|
22 (7.4%)
|
0.492
|
LTOT during sleep
|
414 (70.1%)
|
206 (70.5%)
|
208 (69.6%)
|
0.794
|
LTOT on exertion
|
465 (78.7%)
|
233 (79.8%)
|
232 (77.6%)
|
0.513
|
Oral corticoid
|
153 (25.9%)
|
76 (26.0%)
|
77 (25.8%)
|
0.939
|
Inhaled corticosteroid
|
447 (75.6%)
|
211 (72.3%)
|
236 (78.9%)
|
0.059
|
Short-acting beta-agonist
|
515 (87.1%)
|
264 (90.4%)
|
251 (83.9%)
|
0.019
|
Anticholinergic agent
|
486 (82.2%)
|
242 (82.9%)
|
244 (81.6%)
|
0.686
|
Theophylline
|
238 (40.3%)
|
124 (42.5%)
|
114 (38.1%)
|
0.282
|
Diuretics
|
86 (14.6%)
|
41 (14.0%)
|
45 (15.1%)
|
0.728
|