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Table 2 Cox regression of all-cause mortality in 2,249 patients on long-term oxygen therapy for COPD

From: Hypo- and hypercapnia predict mortality in oxygen-dependent chronic obstructive pulmonary disease: a population-based prospective study

Parameter

Hazard ratio

95% CI

P-value

PaCO2 (air)†

-

-

< 0.001

Age (per y)

1.04

1.03 – 1.05

< 0.001

Male

1.35

1.19 – 1.53

< 0.001

BMI

  

< 0.001*

  < 18.5

1.35

1.14 – 1.60

< 0.001

  18.5- 24.9

Ref

-

-

  25 - 29.9

0.73

0.60 – 0.88

0.001

  ≥ 30

0.80

0.64 – 1.00

0.051

WHO performance status

  

< 0.001*

  0

Ref

-

-

  1

1.01

0.74 – 1.39

0.927

  2

1.47

1.08 – 2.01

0.016

  3

2.26

1.62 – 3.16

< 0.001

  4

3.21

1.94 – 5.30

< 0.001

Missing

1.35

0.95 – 1.93

0.098

PaO2 (air) (per 1 kPa)

0.91

0.85 – 0.98

0.014

Cardiovascular diagnoses

  

< 0.001*

  0

Ref

-

-

  1

1.25

1.08 – 1.46

0.003

  2

1.42

1.20 – 1.68

< 0.001

  > 2

1.38

1.12 – 1.71

0.003

Oral glucocorticoids

1.16

1.02 – 1.31

< 0.001

Opioids

1.19

1.05 – 1.35

0.009

Benzodiazepines

1.18

1.03 – 1.34

0.014

  1. *Wald test of total significance for class variables with more than two categories.
  2. †The p-value is reported for both linear and squared term for PaCO2 (air).
  3. Abbreviations: CI, confidence interval; Ref, reference category.