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Table 1 Demographic characteristics, clinical, and air pollution variables in non-exercise-induced desaturation (EID) and EID groups (N = 141)

From: Association of air pollution exposure with exercise-induced oxygen desaturation in COPD

Variable

All patients (N = 141)

Non-EID (N = 83)

EID (N = 58)

p value

Age (years)

69.33 ± 7.91

68.65 ± 8.156

70.31 ± 7.51

0.2216

Sex (M/F)

126/15

77/6

49/9

0.3981

BMI (kg/m2)

23.25 ± 4.11

23.68 ± 4.01

22.62 ± 4.21

0.1341

Smoking status

   

0.0012

 Smoker (n, %)

62 (44.0)

46 (55.42)

16 (27.59)

 

 Ex-smoker (n, %)

67 (47.5)

32 (38.55)

35 (60.34)

 

 Never smoking (n, %)

12 (8.5)

5 (6.02)

7 (12.07)

 

 Smoking (pack-years)

49.60 ± 35.24

46.52 ± 33.56

54.00 ± 37.36

0.2159

mMRC

1.33 ± 1.07

1.04 ± 0.92

1.76 ± 1.13

 < 0.0001

 CAT

9.54 ± 6.98

8.93 ± 7.12

10.4 ± 6.75

0.2218

Emphysema severity

15.77 ± 9.44

12.50 ± 6.96

20.45 ± 10.55

 < 0.0001

 None (n, %)

28 (19.86)

14 (16.87)

4 (6.90)

 

 Mild (n, %)

26 (18.44)

18 (21.69)

8 (13.79)

 

 Moderate (n, %)

54 (38.30)

38 (45.78)

16 (27.59)

 

 Severe (n, %)

43 (30.50)

13 (15.66)

30 (51.72)

 

AE (time/year)

0.81 ± 1.53

0.43 ± 0.65

1.35 ± 2.13

0.0008

Pulmonary function test

    

 FEV1 (pred %)

55.38 ± 19.96

62.45 ± 17.76

43.87 ± 18.36

 < 0.0001

 FVC (pred %)

78.73 ± 19.74

83.09 ± 18.42

71.01 ± 19.34

0.0003

6 min walking test

    

 (6MWD) (m)

375.1 ± 114.1

398.5 ± 101.0

341.8 ± 124.0

0.0034

 SpO2-pre (%)

94.11 ± 2.34

94.93 ± 1.89

92.95 ± 2.44

 < 0.0001

 SpO2-post (%)

89.06 ± 5.48

92.78 ± 1.84

83.72 ± 4.45

 < 0.0001

 ΔIC (L)

-0.05 ± 0.26

0.01 ± 0.23

-0.14 ± 0.29

0.0025

Air pollution

    

 PM10 (μg/m3)-7 day

32.13 ± 10.62

32.12 ± 10.97

32.15 ± 10.13

0.9894

 PM2.5 (μg/m3)-7 day

16.30 ± 5.44

15.98 ± 5.20

16.82 ± 5.82

0.3954

 NO2 (ppb)-7 day

17.59 ± 3.79

17.74 ± 3.75

17.34 ± 3.89

0.5545

 O3 (ppb)-7 day

29.43 ± 6.55

28.56 ± 5.89

30.86 ± 7.35

0.0526

 PM10 (μg/m3)-10 year

40.71 ± 2.51

40.19 ± 2.35

41.57 ± 2.54

0.0021

 PM2.5 (μg/m3)-10 year

22.64 ± 1.70

22.26 ± 1.49

23.24 ± 1.85

0.0012

 NO2 (ppb)-10 year

20.30 ± 1.84

19.85 ± 1.76

20.88 ± 1.76

0.0007

 O3 (ppb)-10 year

26.18 ± 0.98

26.24 ± 1.02

26.07 ± 0.90

0.3398

Exposure season#

   

0.9801

 Spring (n, %)

39 (27.66)

25 (30.12)

14 (24.14)

 

 Summer (n, %)

30 (21.28)

17 (20.48)

13 (22.41)

 

 Fall (n, %)

46 (32.62)

25 (30.12)

21 (36.21)

 

 Winter (n, %)

26 (18.44)

16 (19.28)

10 (17.24)

 
  1. Data are presented as % or mean ± standard deviation. Severity of emphysema was classified as none (low attenuation area (LAA) < 5%), mild (LAA 5–10%), moderate (LAA 10–20%), or severe (LAA ≥ 20%); SpO2 oxyhemoglobin saturation by pulse oximetry, ΔSpO2 (%) post-exercise saturation—pre-exercise saturation, ΔIC post-exercise inspiratory capacity—pre-exercise inspiratory capacity, BMI body-mass index, AE acute exacerbation, LAA low attenuation area, CAT chronic obstructive pulmonary disease assessment test, IC inspiratory capacity, pred predicted, 6MWD 6 min walking distance, PM10 particulate matter of < 10 μm in aerodynamic diameter, PM2.5 particulate matter of < 2.5 μm in aerodynamic diameter, NO2 nitrogen dioxide, O3 ozone. #Exposure season:Spring (March–May), Summer (June–August), Fall (September–November), Winter (December–February)
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Respiratory Research

ISSN: 1465-993X

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