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

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Abstract

Background: The prognostic role of the arterial blood gas tension of carbon dioxide (PaCO2) in severe Chronic Obstructive Pulmonary Disease (COPD) remains unknown. The aim of this study was to estimate the association between PaCO2 and mortality in oxygen-dependent COPD. Methods: National prospective study of patients starting long-term oxygen therapy (LTOT) for COPD in Sweden between October 1, 2005 and June 30, 2009, with all-cause mortality as endpoint. The association between PaCO2 while breathing air, PaCO2 (air), and mortality was estimated using Cox regression adjusted for age, sex, arterial blood gas tension of oxygen (PaO2), World Health Organization performance status, body mass index, comorbidity, and medications. Results: Of 2,249 patients included, 1,129 (50%) died during a median 1.1 years (IQR 0.6-2.0 years) of observation. No patient was lost to follow-up. PaCO2 (air) independently predicted adjusted mortality (p < 0.001). The association with mortality was U-shaped, with the lowest mortality at approximately PaCO2 (air) 6.5 kPa and increased mortality at PaCO2 (air) below 5.0 kPa and above 7.0 kPa. Conclusion: In oxygen-dependent COPD, PaCO2 (air) is an independent prognostic factor with a U-shaped association with mortality.

Details

Authors
Organisations
External organisations
  • Blekinge Hospital
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Respiratory Medicine and Allergy

Keywords

  • COPD, LTOT, Mortality, PaCO2, Hypercapnia, Carbon dioxide, Respiratory, failure, Survival
Original languageEnglish
Article number30
JournalRespiratory Research
Volume15
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes

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