COPD: acute exacerbation caused by heart failure decreased risk of dying.

Clinical bottom line (level 1b)

  1. A third of patients with an acute exacerbation of chronic obstructive pulmonary disease died within 180 days.
  2. Patients with an acute exacerbation of COPD were less likely to die within 180 days if they had heart failure as the cause of the exacerbation.
  3. A difference in acute physiology score, age, activities of daily living score and number of co morbid illnesses may be associated with an increased risk of dying.
  4. A difference in body mass index, PaO 2 /FIO 2 , albumin and presence of Cor Pulmonale may be associated with a decreased risk of dying.
Connors et al: American Journal of Respiratory Critical Care Medicine 1996; 154: 959-967
Expires November 2003

The study

Prospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: 5 centres, USA

1016 patients (aged median 70 years, 52% male) Severe chronic obstructive pulmonary disease, defined by meeting the three criteria: clinical diagnosis of COPD recorded in the chart by a physician (COPD, chronic obstructive lung disease, chronic airways obstruction, emphysema or chronic bronchitis were accepted); breathlessness, respiratory failure or change in mental status due to COPD as the main reason for admission; documentation of hypercapnia (PaCO2 of 50 mmHg or more either on the day of admission or within 1 week prior to admission)

Excluded if
  • <18 years old
  • death or discharge within 24 hours
  • inability to speak English
  • acute psychiatric disorders
  • pregnancy
  • acquired immune deficiency syndrome
  • acute burns
  • head trauma or other trauma (unless patient later developed acute respiratory failure or multi organ system failure)



    • Factors studied:
  • mortality
  • acute physiology score (taken from the APACHE III)-10 point difference
  • body mass index (weight in kg/height im m ² )- 5 kg/m ² difference
  • age, 10-year difference
  • Activities of daily living score, 1 point difference
  • PaO 2 /FIO 2 , 100 mmHg difference
  • congestive heart failure as cause of exacerbation
  • albumin, 1g/100 cc difference
  • Cor pulmonale clinical diagnosis by a physician or presence of 2 or more of: right ventricular hypertrophy or right atrial enlargement on ECG; enlarged pulmonary arteries on chest roentgenogram; pedal oedema; jugular venous distention; mean pulmonary artery pressure >20 mmHg as measured by pulmonary artery catheter
  • number of comorbid illnesses




    • Cox proportional hazards model was used to adjust for confounding factors.

    followed for 180 days
    Outcomes studied:
  • mortality

    • Chart abstractors supervisors were trained centrally and all sites had a quarterly site visit to assure compliance with the study protocol. Ten percent of all charts were selected using a random process for reabstraction by a second abstractor to ensure the quality of data.

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    mortality 180 days 331/1016 32.6%
    (64.5% to 70.3%)

    prognostic factor for
    mortality     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    acute physiology score (taken from the APACHE III)-10 point difference 180 days 1.32
    (1.20 to 1.45)
    body mass index (weight in kg/height im m ² )- 5 kg/m ² difference 180 days 0.75
    (0.67 to 0.85)
    age, 10-year difference 180 days 1.22
    (1.05 to 1.41)
    Activities of daily living score, 1 point difference 180 days 1.14
    (1.03 to 1.26)
    PaO 2 /FIO 2 , 100 mmHg difference 180 days 0.78
    (0.65 to 0.95)
    congestive heart failure as cause of exacerbation 180 days 0.66
    (0.45 to 0.97)     		-11
    (-130 to -7)
    albumin, 1g/100 cc difference 180 days 0.73
    (0.55 to 0.98)
    Cor pulmonale 180 days 0.67
    (0.45 to 0.99)
    number of comorbid illnesses 180 days 1.13
    (0.99 to 1.28)

    Comments

    1. A 10 point difference in acute physiology score, a 10 year difference in age, a 1 point difference in activities of daily living score and number of co morbid illnesses were all associated with increased mortality, but no NNFs could be calculated.
    2. A 5 kg/m ² difference in body mass index, a 100 mmHg difference in PaO2/FIO2, a 1g/100 cc difference in albumin and Cor pulmonale were all associated with a decrease in mortality, but no NNFs could be calculated.

    Citation

    1. Connors AF, Dawson NV, Thomas C, et al: Outcomes following acute exacerbations of severe chronic obstructive lung disease. American Journal of Respiratory Critical Care Medicine 1996; 154: 959-967
    Search Terms: COPD, chronic obstructive pulmonary disease and prognosis in Medline and Cochrane
    Contributor: Clare Wotton and Musab Hayatli, November 1999
    Reviewer: Mitsuhiro Kamei

    Clinical Question.
    Patient acute exacerbation of COPD
    Intervention or Exposure risk factors
    Comparison
    Outcome