NIHR DC Discover

NIHR Signal Home oxygen therapy prescribed for 15 hours a day did not reduce breathlessness at six months and is hard to take for people with severe chronic heart failure

Published on 7 January 2016

doi: 10.3310/signal-000176

This NIHR-funded trial found no evidence that long-term home oxygen therapy improves symptoms or quality of life for people with severe chronic heart failure. There were encouraging signs after three months but these were not sustained at six months by which time there was no difference between the oxygen therapy group, who continued to receive best medical care, and the control group. The trial was stopped early due to poor adherence to the therapy and so was unable to furnish strong evidence.

Patients were prescribed 15 hours a day of oxygen therapy, but only used on average just over five hours; only one in ten participants used the therapy as prescribed. These limitations mean that the results need to be treated with caution. However, given the lack of clear evidence of benefit and the expensive and burdensome nature of home oxygen therapy, the treatment is unlikely to be cost-effective.

Share your views on the research.

Why was this study needed?

Chronic heart failure affects at least 1% of the population and is responsible for around 4% of all admissions to hospital in the UK. It is estimated that the cost of heart failure is around 2% of the total NHS budget; nearly three-quarters of this is due to the costs of hospitalisation.

People with severe chronic heart failure often suffer from breathlessness. Home oxygen therapy is commonly prescribed in order to relieve symptoms although, unlike the situation for patients with chronic obstructive pulmonary disease, there is no evidence to support the use of home oxygen therapy in patients with chronic heart failure.

The NIHR funded this trial to look at whether or not home oxygen therapy improved the quality of life of people with severe chronic heart failure.

What did this study do?

This was a randomised controlled trial of long-term home oxygen therapy versus standard care of 114 patients with severe chronic heart failure. Patients were on average 70 years of age and 70% were men. All of them had severe symptoms of breathlessness either at rest or after minimal exertion. Patients were excluded if they had hypoxia, low oxygen levels in the blood.

Oxygen therapy was delivered in the patients’ homes via a machine called an oxygen concentrator. Oxygen was prescribed for 15 hours per day, similar to standard practice for patients with chronic obstructive pulmonary disease. The oxygen concentrator delivered air with about 28% oxygen, up from the 20.9% found in normal room air. All participants received standard medical therapy.

The original target was 222 patients but the trial was stopped because of poor patient adherence to the prescribed therapy. The trial was therefore underpowered and so the results need to be treated with caution.

What did it find?

  • After three months, there was an additional improvement in quality of life of about five points on a 105 point scale in the oxygen therapy group compared to the control group (change in adjusted mean Minnesota Living with Heart Failure questionnaire score -5.47, 95% confidence interval -10.54 to -0.41). Breathlessness scores also improved.
  • However, after six months there was no difference. Both groups had improved by about five to six points on a 105 point scale.
  • Only 11% of patients reported using the therapy as prescribed. Participants used the oxygen for an average of a little over five hours a day, rather than the 15 hours prescribed.

What does current guidance say on this issue?

NICE does not have guidance on the use of home oxygen therapy for people with chronic heart failure. However, the National Service Framework for coronary heart disease, published in 2000, recommends considering the potential benefit from “palliative care services and palliation aids (e.g. home oxygen)”.

The British Thoracic Society recommends that home oxygen therapy may be helpful for people with severe chronic heart failure, though only if they also suffer from hypoxaemia, low levels of oxygen in the blood.

What are the implications?

Because the trial was underpowered, interpretation is difficult. The results provide no evidence that long-term home oxygen therapy improves quality of life for people with severe chronic heart failure. However the authors acknowledge that it is not possible to distinguish whether the lack of a detected effect is a result of the trial being underpowered or whether there is a true lack of effect. The low adherence may also have reduced the impact of therapy.

Oxygen therapy can be burdensome. It limits mobility, it can cause soreness around the nose and the equipment is noisy. The concentrator has to be fitted to the home, usually requiring some drilling through walls. The machine uses electricity, the costs of which are normally met by the NHS. Home oxygen therapy is therefore expensive to the health service and burdensome to the patient, and the results of this trial, while preliminary in nature, suggest that it is not money well spent as a treatment for heart failure. It is possible that emergency use of oxygen, from an oxygen bottle, could still be of use for severe episodes of breathlessness and might reduce hospital admissions. The authors suggest that this could be studied further.

Citation

Clark AL, Johnson M, Fairhurst C, et al. Does home oxygen therapy (HOT) in addition to standard care reduce disease severity and improve symptoms in people with chronic heart failure? A randomised trial of home oxygen therapy for patients with chronic heart failure. Health Technol Assess. 2015;19(75):1-120.

This project was funded by the National Institute for Health Research Health Technology Assessment programme (project number 06/80/01).

Bibliography

Hardinge M, Annandale J, Bourne S, et al. British Thoracic Society guidelines for home oxygen use in adults. Thorax. 2015;70 Suppl 1: i1-43.

Minnesota Living With Heart Failure Questionnaire. Technology #94019. Minneapolis (MN): University of Minnesota; 2015.

NHS. National Service Framework for Coronary Heart Disease. London: Department of Health; 2000.

NICE. Chronic heart failure. Costing report. Implementing NICE guidance. London: National Institute for Health and Care Excellence; 2010.

NICE. Chronic heart failure in adults: management. CG108. London: National Institute for Health and Care Excellence; 2010.

Why was this study needed?

Chronic heart failure affects at least 1% of the population and is responsible for around 4% of all admissions to hospital in the UK. It is estimated that the cost of heart failure is around 2% of the total NHS budget; nearly three-quarters of this is due to the costs of hospitalisation.

People with severe chronic heart failure often suffer from breathlessness. Home oxygen therapy is commonly prescribed in order to relieve symptoms although, unlike the situation for patients with chronic obstructive pulmonary disease, there is no evidence to support the use of home oxygen therapy in patients with chronic heart failure.

The NIHR funded this trial to look at whether or not home oxygen therapy improved the quality of life of people with severe chronic heart failure.

What did this study do?

This was a randomised controlled trial of long-term home oxygen therapy versus standard care of 114 patients with severe chronic heart failure. Patients were on average 70 years of age and 70% were men. All of them had severe symptoms of breathlessness either at rest or after minimal exertion. Patients were excluded if they had hypoxia, low oxygen levels in the blood.

Oxygen therapy was delivered in the patients’ homes via a machine called an oxygen concentrator. Oxygen was prescribed for 15 hours per day, similar to standard practice for patients with chronic obstructive pulmonary disease. The oxygen concentrator delivered air with about 28% oxygen, up from the 20.9% found in normal room air. All participants received standard medical therapy.

The original target was 222 patients but the trial was stopped because of poor patient adherence to the prescribed therapy. The trial was therefore underpowered and so the results need to be treated with caution.

What did it find?

  • After three months, there was an additional improvement in quality of life of about five points on a 105 point scale in the oxygen therapy group compared to the control group (change in adjusted mean Minnesota Living with Heart Failure questionnaire score -5.47, 95% confidence interval -10.54 to -0.41). Breathlessness scores also improved.
  • However, after six months there was no difference. Both groups had improved by about five to six points on a 105 point scale.
  • Only 11% of patients reported using the therapy as prescribed. Participants used the oxygen for an average of a little over five hours a day, rather than the 15 hours prescribed.

What does current guidance say on this issue?

NICE does not have guidance on the use of home oxygen therapy for people with chronic heart failure. However, the National Service Framework for coronary heart disease, published in 2000, recommends considering the potential benefit from “palliative care services and palliation aids (e.g. home oxygen)”.

The British Thoracic Society recommends that home oxygen therapy may be helpful for people with severe chronic heart failure, though only if they also suffer from hypoxaemia, low levels of oxygen in the blood.

What are the implications?

Because the trial was underpowered, interpretation is difficult. The results provide no evidence that long-term home oxygen therapy improves quality of life for people with severe chronic heart failure. However the authors acknowledge that it is not possible to distinguish whether the lack of a detected effect is a result of the trial being underpowered or whether there is a true lack of effect. The low adherence may also have reduced the impact of therapy.

Oxygen therapy can be burdensome. It limits mobility, it can cause soreness around the nose and the equipment is noisy. The concentrator has to be fitted to the home, usually requiring some drilling through walls. The machine uses electricity, the costs of which are normally met by the NHS. Home oxygen therapy is therefore expensive to the health service and burdensome to the patient, and the results of this trial, while preliminary in nature, suggest that it is not money well spent as a treatment for heart failure. It is possible that emergency use of oxygen, from an oxygen bottle, could still be of use for severe episodes of breathlessness and might reduce hospital admissions. The authors suggest that this could be studied further.

Citation

Clark AL, Johnson M, Fairhurst C, et al. Does home oxygen therapy (HOT) in addition to standard care reduce disease severity and improve symptoms in people with chronic heart failure? A randomised trial of home oxygen therapy for patients with chronic heart failure. Health Technol Assess. 2015;19(75):1-120.

This project was funded by the National Institute for Health Research Health Technology Assessment programme (project number 06/80/01).

Bibliography

Hardinge M, Annandale J, Bourne S, et al. British Thoracic Society guidelines for home oxygen use in adults. Thorax. 2015;70 Suppl 1: i1-43.

Minnesota Living With Heart Failure Questionnaire. Technology #94019. Minneapolis (MN): University of Minnesota; 2015.

NHS. National Service Framework for Coronary Heart Disease. London: Department of Health; 2000.

NICE. Chronic heart failure. Costing report. Implementing NICE guidance. London: National Institute for Health and Care Excellence; 2010.

NICE. Chronic heart failure in adults: management. CG108. London: National Institute for Health and Care Excellence; 2010.

Does home oxygen therapy (HOT) in addition to standard care improve disease severity and symptoms in chronic heart failure?

Published on 23 September 2015

Clark AL, Johnson M, Fairhurst C, Torgerson D, Cockayne S, Rodgers S, Griffin S, Allgar V, Jones L, Nabb S, Harvey I, Squire I, Murphy J, Greenstone M

Health Technology Assessment Volume 19 Issue 75 , 2015

Background Home oxygen therapy (HOT) is commonly used for patients with severe chronic heart failure (CHF) who have intractable breathlessness. There is no trial evidence to support its use. Objectives To detect whether or not there was a quality-of-life benefit from HOT given as long-term oxygen therapy (LTOT) for at least 15 hours per day in the home, including overnight hours, compared with best medical therapy (BMT) in patients with severely symptomatic CHF. Design A pragmatic, two-arm, randomised controlled trial recruiting patients with severe CHF. It included a linked qualitative substudy to assess the views of patients using home oxygen, and a free-standing substudy to assess the haemodynamic effects of acute oxygen administration. Setting Heart failure outpatient clinics in hospital or the community, in a range of urban and rural settings. Participants Patients had to have heart failure from any aetiology, New York Heart Association (NYHA) class III/IV symptoms, at least moderate left ventricular systolic dysfunction, and be receiving maximally tolerated medical management. Patients were excluded if they had had a cardiac resynchronisation therapy device implanted within the past 3 months, chronic obstructive pulmonary disease fulfilling the criteria for LTOT or malignant disease that would impair survival or were using a device or medication that would impede their ability to use LTOT. Interventions Patients received BMT and were randomised (unblinded) to open-label LTOT, prescribed for 15 hours per day including overnight hours, or no oxygen therapy. Main outcome measures The primary end point was quality of life as measured by the Minnesota Living with Heart Failure (MLwHF) questionnaire score at 6 months. Secondary outcomes included assessing the effect of LTOT on patient symptoms and disease severity, and assessing its acceptability to patients and carers. Results Between April 2012 and February 2014, 114 patients were randomised to receive either LTOT or BMT. The mean age was 72.3 years [standard deviation (SD) 11.3 years] and 70% were male. Ischaemic heart disease was the cause of heart failure in 84%; 95% were in NYHA class III; the mean left ventricular ejection fraction was 27.8%; and the median N-terminal pro-B-type natriuretic hormone was 2203 ng/l. The primary analysis used a covariance pattern mixed model which included patients only if they provided data for all baseline covariates adjusted for in the model and outcome data for at least one post-randomisation time point (n = 102: intervention, n = 51; control, n = 51). There was no difference in the MLwHF questionnaire score at 6 months between the two arms [at baseline the mean score was 54.0 (SD 18.4) for LTOT and 54.0 (SD 17.9) for BMT; at 6 months the mean score was 48.1 (SD 18.5) for LTOT and 49.0 (SD 20.2) for BMT; adjusted mean difference –0.10, 95% confidence interval (CI) –6.88 to 6.69; p = 0.98]. At 3 months, the adjusted mean MLwHF questionnaire score was lower in the LTOT group (–5.47, 95% CI –10.54 to –0.41; p = 0.03) and breathlessness scores improved, although the effect did not persist to 6 months. There was no effect of LTOT on any secondary measure. There was a greater number of deaths in the BMT arm (n = 12 vs. n = 6). Adherence was poor, with only 11% of patients reporting using the oxygen as prescribed. Conclusions Although the study was significantly underpowered, HOT prescribed for 15 hours per day and subsequently used for a mean of 5.4 hours per day has no impact on quality of life as measured by the MLwHF questionnaire score at 6 months. Suggestions for future research include (1) a trial of patients with severe heart failure randomised to have emergency oxygen supply in the house, supplied by cylinders rather than an oxygen concentrator, powered to detect a reduction in admissions to hospital, and (2) a study of bed-bound patients with heart failure who are in the last few weeks of life, powered to detect changes in symptom severity. Funding This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 75. See the NIHR Journals Library website for further project information.

The Minnesota Living with Heart Failure Questionnaire is a patient self-assessment of how heart failure affects daily life. It is a short questionnaire of 21 items, taking about five to ten minutes to complete. Most of the questions are on the different ways heart failure affects patients' quality of life, split into two domains: physical and emotional. All questions are answered using a 0 to 5 Likert scale. Scores range from 0 to 105.

The questionnaire includes questions on: shortness of breath, fatigue, difficulty sleeping, anxiety and depression. In addition, questions cover the effects of heart failure on physical and social functions, including walking, climbing stairs, household work, need to rest, working to earn a living, going places away from home, doing things with family or friends, recreational activities, sexual activities, eating and mental and emotional functions of concentration, memory, loss of self control, and being a burden to others.

Expert commentary

Oxygen is very commonly used to help relieve symptoms in patients with very symptomatic heart failure, particularly towards the end of life. However, it is potentially burdensome and expensive. Our study showed that home oxygen treatment did not help improve quality of life or to improve the severity of heart failure. We also found no evidence that it would improve outlook. The findings will help guide palliative care in people with severe heart failure.

Professor Andrew L Clark, Chair of Clinical Cardiology and Honorary Consultant Cardiologist, Castle Hill Hospital, Cottingham