Survival and quality of life for patients with COPD or asthma admitted to intensive care in a UK multicentre cohort: the COPD and Asthma Outcome Study (CAOS)

M J Wildman, C F B Sanderson, J Groves, B C Reeves, J G Ayres, D Harrison, D Young, K Rowan
Thorax 2009;64:128–132. doi:10.1136/thx.2007.091249

There is an unwillingness to admit COPD and asthmatic patients to the intensive care unit, especially if that involves intubation. It is still fairly commonly believed that to do so will probably mean that we will never get the patient off the ventilator, in the long run probably contributing to their demise.

This study examined the outcomes of patients with COPD admitted to the intensive care unit for decompensated type II respiratory failure.


A prospective cohort study.

All ICU’s participating in the UK Case Mix Programme were invited to take part in the study.

Inclusion criteria

Patients admitted with breathlessness, respiratory failure or change in mental status due to an exacerbation of obstructive lung disease. Clinicians were asked to classify the patient as having either COPD, asthma or a mix of the two.

Exclusion criteria

Patients under 45 years of age as it was felt they would be admitted anyway. Surgery within the last 10 days or had been transferred from another hospital.

Data collected-

Patients function during 2 week period of stability before admission using a 4 point scale.

If patient was discharged or died before being intubated, clinicians were asked whether intubation had been ruled out as a treatment option were NIV to fail.

Theses were then classified into 1) intubation not needed; 2) intubated; and 3) not to be intubated.

Survival to 180 days was determined form the GP and a follow up questionnaire was sent to assess their current state of health compared to their pre admission status.


Patients recruited

92 ICU’s participated in the study and they were similar to others in terms of size, type, affiliation and the mean percentages of admissions potentially eligible for the study.

832 patients were recruited to the study.

(From the CMP database data were extracted which suggested that there were some units that were more selective than others about which patients with COPD/asthma they admitted.)

Ventilation and length of stay.

81.3% were admitted only to the ITU and 54.1% were intubated before or during ITU admission.

36.5% were not intubated but had NIV and 8.1% had medical treatment only.

47% of the non intubated patients were deemed “not to be intubated”.

Of the patients designated ‘‘not to be intubated’’, 57% had been admitted directly to the ICU. They tended to be older than the others (mean age 70.3 vs 66.1 years) and had slightly lower mean COPD acute physiology scores (26.4 vs 28.4). They had much lower functional scores (housebound or worse 68.0% vs 30.0%), and 75.1% were either housebound or on long-term oxygen or both compared with 32.7% in the intubated group.


62.1% survived to 180 days.

Survival rates were highest in patients who did not need intubation and lowest in those designated ‘‘not to be intubated’’, but the differences in survival between the intubated COPD¡ and the ‘‘not to be intubated’’ groups were quite small.Image 1

Quality of life at 180 days.

73% of respondents stated that their current state of health was the same as or better than before hospitalisation.

62% of the respondents experienced moderate or extreme discomfort and 56% had some anxiety/depression, 7% rating this as extreme. Generally, the quality of life in the not- to-be-intubated group was poorer than for the rest.

Willingness to undergo similar treatment in the future.

96% of the 415 who answered the question about whether they would be willing to undergo similar treatment again under the same circumstances said that they would.

Predictors of quality of life on follow up.

The actual agreement between function before admission to the ICU and on follow-up was quite low but the correlation between the two (and therefore the discriminatory power of pre-admission function) was reasonably good, so pre-admission functional status gives clinicians useful information about likely status on follow-up.

As a rule of thumb, those who were housebound before admission will probably be the same at follow-up, but the most common (and equally likely) outcome for those who were fully mobile or independent is that they will stay the same or fall one category.


  • Study results least applicable to those admitted to hospital on long term oxygen
  • Assessment of patients to diagnostic group was based on clinical judgement. Cannot be certain that those classified as having pure asthma really did have asthma or that some of the younger patients with COPD did have the condition.

“Functional capacity in the period of stability in the 2 weeks before hospital admission is a reasonably discriminating indicator of function at 180 days. Although survivors still had impaired quality of life, almost all of them would have wanted similar treatment again. We think that these findings should inform decision making for patients who are being considered for intubation.”

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Originally posted 2014-09-05 16:05:10. Republished by Blog Post Promoter

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