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Table 1 Baseline characteristics classified by arterial oxygen saturation (SpO 2 ) in 5,152 participants

From: Low oxygen saturation and mortality in an adult cohort: the Tromsø study

 

≤92%

93–95%

≥96%

p-value

 

n

(%)

n

(%)

n

(%)

 

All

 

53

(1.0)

537

(10.4)

4,562

(88.5)

Sex

      

0.47

  Female

34

(1.2)

297

(10.3)

2,556

(88.5)

 

  Male

19

(0.8)

240

(10.6)

2,006

(88.6)

 

Age (years)

      

<0.001*

  <60

1

(0.1)

57

(5.3)

1,027

(94.7)

 

  60–70

16

(0.7)

217

(10.2)

1,902

(89.1)

 

  ≥70

36

(1.9)

263

(13.6)

1,633

(84.5)

 

Self-reported diseases

      

CVD

     

<0.001

  No

39

(0.9)

410

(9.6)

3,814

(89.5)

 

  Yes

14

(1.6)

127

(14.3)

748

(84.1)

 

Asthma

     

<0.001

  No

37

(0.8)

448

(9.6)

4,197

(89.6)

 

  Yes

16

(3.4)

89

(18.9)

365

(77.7)

 

COPD

     

<0.001

  No

39

(0.8)

476

(9.8)

4,366

(89.4)

 

  Yes

14

(5.2)

61

(22.5)

196

(72.3)

 

Diabetes

     

0.004

  No

49

(1.0)

499

(10.1)

4,373

(88.9)

 

  Yes

4

(1.7)

38

(16.5)

189

(81.8)

 

Hypertension

     

0.020

  No

40

(1.0)

378

(9.7)

3,463

(89.2)

 

  Yes

13

(1.0)

159

(12.5)

1099

(86.5)

 

Smoking history

     

0.001*

  Never

16

(0.9)

141

(8.1)

1,581

(91.0)

 

  Former

21

(1.0)

241

(11.6)

1,819

(87.4)

 

  Current

16

(1.2)

155

(11.6)

1,162

(87.2)

 

Self-reported symptoms

      

Dyspnoea#

      

<0.001*

  0

17

(0.6)

221

(8.0)

2,511

(91.3)

 

  1

17

(0.8)

244

(11.9)

1,785

(87.2)

 

  ≥2

19

(5.3)

72

(20.2)

266

(74.5)

 

Chronic cough with sputum

     

<0.001

  No

44

(0.9)

460

(9.7)

4,261

(89.4)

 

  Yes

9

(2.3)

77

(19.9)

301

(77.8)

 

BMI (kg/m2)

     

<0.001*

  <18.5

1

(2.0)

6

(12.2)

42

(85.7)

 

  18.5-24.9

16

(1.0)

107

(6.4)

1,548

(92.6)

 

  25.0-29.9

21

(0.9)

239

(10.2)

2,082

(88.9)

 

  ≥30.0

15

(1.4)

180

(17.0)

865

(81.6)

 

CRP (mg/L)

     

<0.001

  <5

36

(0.8)

421

(9.7)

3,871

(89.4)

 

  ≥5

17

(2.3)

109

(14.7)

615

(83.0)

 

Haemoglobin§

     

0.29

  ≤upper limit

48

(1.0)

469

(10.3)

4,052

(88.7)

 

  >upper limit

0

(0.0)

4

(21.1)

15

(78.9)

 

FEV1% predicted

     

<0.001*

  <50

16

(8.2)

66

(34.0)

112

(57.7)

 

  50–80

22

(1.3)

223

(13.3)

1,427

(85.3)

 

  ≥80

13

(0.4)

227

(7.3)

2,882

(92.3)

 

FEV1/FVC%

     

<0.001

  <0.7

26

(2.4)

185

(16.8)

890

(80.8)

 

  ≥0.7

25

(0.6)

335

(8.6)

3,551

(90.8)

 
  1. *Chi-square trend.
  2. #Dyspnoea: 0, no dyspnoea; 1, dyspnoea walking rapidly on level ground or up a moderate slope; ≥2, dyspnoea walking slowly on level ground, washing or dressing, or at rest.
  3. §Upper limits: women, 16.0 g/dL; men, 17.0 g/dL.
  4. Definitions of abbreviations: SpO2, arterial oxygen saturation as measured by pulse oximetry; CVD, cardiovascular disease; COPD, chronic obstructive pulmonary disease; BMI, body mass index; CRP, C-reactive protein; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.
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BMC Pulmonary Medicine

ISSN: 1471-2466

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