COPD: continuous oxygen reduces mortality in severe hypoxia, but not in mild-moderate cases

Clinical bottom line (level 1a)

  1. Patients with COPD and pO2 < 8.0 kPa who receive home oxygen compared with no treatment are less likely to die (NNT = 5 at 5 years) .
  2. Patients with COPD and hypoxia who receive continuous oxygen therapy compared with nocturnal oxygen therapy are less likely to die (NNT = 5 at 2 years) .
  3. Patients with COPD and nocturnal sleep desaturation who received noctural oxygen compared with room air were not clearly less likely to die at 3 years.
  4. Patients with COPD and mild to moderate hypoxia who receive oxygen therapy compared with none are not clearly less likely to die at 3 years.
Crockett et al: Cochrane Library 2000; 3 : -
Expires October 2003

The study

Systematic review of all randomised controlled trials of
  • Patients: COPD and hypoxia (usually pO2 < 7.3 kPa, but some > 7.3 kPa with evidence of nocturnal hypoxia or desaturation with exercise)
  • Intervention: home oxygen compared with no treatment
  • Outcome: death, quality of life

    Articles found in ?all languages using Cochrane Airways Group COPD register, - (search terms: home or domiciliary and oxygen ) and searching bibliographies of retrieved papers for relevant studies. Authors, relevant companies and members of the International Respiratory Care Club were contacted for unpublished studies.

    Selection criteria:
    Appraisal criteria: by 2 independent reviewers: based on blinding
    Articles excluded if:

    5 RCTs were found
    • Data from 2 studies on nocturnal oxygen in mild-moderate hypoxia were aggregated, but the others were too diverse in treatment and types of patients to be combined.

    The evidence

    Outcome Time to outcome CER OR
    (95% CI)    		 NNT
    (95% CI)
    oxygen v. no therapy: death 5 years 30/45
    (66.7%)    		 0.42
    (0.18 to 0.98)     		5
    (2 to 98)
    continuous oxygen v. nocturnal oxygen: death 2 years 102/41
    (40.2%)    		 0.45
    (0.25 to 0.81)     		5
    (3 to 11)
    nocturnal oxygen v. room air: death 3 years 13/54
    (24.1%)    		 0.97
    (0.41 to 2.31)     		180
    (NNT = 8 to infinity;
    NNH = 5 to infinity)
    moderate hypoxia: long-term oxygen v. no therapy: death 3 years 67/32
    (47.8%)    		 1.38
    (0.70 to 2.71)     		-12
    (NNT = 11 to infinity;
    NNH = 4 to infinity)

    Citation

    1. Crockett AJ, Cranston JM, Moss JR, et al: domicillary oxygen for chronic obstructive pulmonary disease. Cochrane Library 2000; 3 : -
    Search Terms: COPD in Cochrane Library
    Contributor: Chris Ball, October 2001
    Reviewer:

    Clinical Question.
    Patient COPD and hypoxia
    Intervention or Exposure home oxygen
    Comparison no treatment
    Outcome death, quality of life