Table 2 Baseline characteristics of patients in the propensity-score-matched cohort

Age (year)

66.3 ± 5.0

66.6 ± 5.3

0.295

Sex (female)

23 (35.4%)

69 (35.4%)

1

Race (not white)

3 (4.6%)

10 (5.1%)

0.870

Annual income < 30,000$

36 (55.4%)

100 (51.3%)

0.566

% predicted FEV₁

26.4 ± 6.8

26.0 ± 6.6

0.461

[FEV₁ (L)]

0.78 ± 0.22

0.76 ± 0.25

0.294

[FEV₁/FVC (%)]

30.9 ± 5.6

31.0 ± 6.0

0.746

% predicted FVC

66.9 ± 13.8

66.1 ± 14.6

0.653

[FVC (L)]

2.53 ± 0.64

2.51 ± 0.78

0.644

Forced residual capacity (L)

6.05 ± 1.22

6.05 ± 1.24

0.986

Hemoglobin adjusted DL_CO

7.8 ± 3.0

7.9 ± 3.0

0.733

[Peak Pulmonary Artery Pressure (mmHg)]

33.8 ± 6.0

34.0 ± 6.6

0.782

(N = 55)

(N = 167)

Hemoglobin (g/dl)

14.4 ± 1.1

14.3 ± 1.3

0.676

PaO₂ (mmHg)

63.3 ± 10.2

63.3 ± 9.8

0.989

PaCO₂ (mmHg)

43.4 ± 5.7

43.7 ± 6.2

0.679

[Area of emphysema (%)]

13.5 ± 9.4

15.9 ± 9.8

0.085

(N = 60)

(N = 173)

Body mass index (kg/m^2)

24.7 ± 3.6

24.6 ± 3.5

0.791

Six − minute walk distance

362 ± 79

366 ± 90

0.689

St. George Respiratory Questionnaire

53.8 ± 11.8

53.9 ± 13.3

0.892

Shortness of Breath Questionnaire

64.0 ± 16.4

63.8 ± 18.9

0.915

Beck Depression Inventory

9.0 ± 5.9

9.1 ± 6.3

0.988

Recent emergency visit

13 (20.0%)

34 (17.4%)

0.642

Recent hospital stay

9 (13.9%)

24 (12.3%)

0.747

LTOT during sleep

48 (73.8%)

144 (73.8%)

1

LTOT on exertion

50 (76.9%)

155 (79.5%)

0.661

Inhaled corticosteroids

49 (75.4%)

140 (71.8%)

0.574

Long acting beta agonist

31 (47.7%)

94 (48.2%)

0.942

Short acting beta agonist

57 (87.7%)

167 (85.6%)

0.678

Anticholinergic agent

49 (75.4%)

155 (79.5%)

0.486

Theophylline

30 (46.2%)

91 (46.7%)

0.943

Diuretics

11 (16.9%)

31 (15.9%)

0.846