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NIHR Signal Continuous positive airway pressure led to less daytime sleepiness in older adults with sleep apnoea

Published on 19 August 2015

doi: 10.3310/signal-000108

This NIHR trial found that continuous positive airway pressure for obstructive sleep apnoea in people aged 65 and over led to less daytime sleepiness and was reasonable value for money. Obstructive sleep apnoea causes the airway to close intermittently overnight leading to daytime sleepiness. It is most common in older people, but previous studies have generally focused on middle-aged people. NIHR commissioned the trial to address this evidence gap. The study can be considered alongside NICE guidance which recommends that the devices be offered to people with obstructive sleep apnoea who have not responded to initial treatment such as lifestyle changes.

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Why was this study needed?

Obstructive sleep apnoea is a fairly common condition, affecting 2-4% of middle-aged people and up to 20% of older people. The muscle and soft tissue in the throat relax during sleep, temporarily blocking the supply of air to the lungs. This disrupts the peron’s sleep – they wake up or sleep lighter during the night – causing sleepiness in the daytime. This can increase their risk of road traffic accidents from falling asleep at the wheel. One treatment - continuous positive airway pressure (CPAP) – involves wearing a face mask that continuously pumps a small amount of pressurised air into the throat to prevent it collapsing during the night. A 2008 meta-analysis for NICE found that CPAP reduced daytime sleepiness and was cost effective in middle-aged people. However, the evidence was less clear in older people. The NIHR funded this study to measure the clinical and cost effectiveness of CPAP in older adults, aged 65 or more, with newly diagnosed obstructive sleep apnoea.

What did this study do?

The PREDICT randomised controlled trial (RCT) randomly allocated 278 people aged 65 and over, with obstructive sleep apnoea syndrome to receive either “best supportive care” only, or best supportive care with CPAP. Best supportive care was defined as advice on minimising daytime sleepiness through lifestyle changes – such as improving sleep hygiene, napping, caffeine or losing weight if appropriate. The RCT took place in 12 NHS sleep clinics across the UK. Sleep clinic staff measuring sleep outcomes were unaware of the treatment participants had received, reducing potential bias in their assessments. Data analyses were pre-specified, reducing the risk of bias at this stage.

What did it find?

  • 231 participants were assessed at 3 and 12 months and included in the analysis. After three months, CPAP with best supportive care improved self-reported sleepiness by an average of 3.8 points (from 11.5 to 7.7) on a 0 to 24 sleep scale. This was a slightly larger improvement than best supportive care only, average improvement 2.0 points (from 11.4 to 9.8). A score of 11 or above indicates possible sleep apnoea, whereas a score of 10 or below is considered normal. CPAP remained the marginally better treatment by 2.0 points (95% confidence interval [CI]  2.8 to  1.2) after 12 months.
  • The average annual cost was comparable between CPAP (£1,363) and best supportive care (£1,389). In the economic analysis, CPAP appeared to be a cost-effective alternative to BSC alone. CPAP decreased costs by a small amount and improved health outcomes. However, the differences in costs and health outcomes between the treatment groups were small and uncertain. The probability that CPAP would be cost-effective at the NHS threshold of £20,000 per QALY gained was 61%, using the EQ-5D scale to measure health related quality of life.
  • General and disease-specific quality of life improved more in those receiving CPAP. Both groups experienced improvements in daily functions and reduced night-time urination. There was no change in incidence of road traffic accidents.

What does current guidance say on this issue?

2008 NICE guidelines recommend that people with moderate or severe obstructive sleep apnoea are offered CPAP if their sleep apnoea affects their daily life – such as falling asleep at work – and if other treatments or lifestyle changes have not been successful.

What are the implications?

PREDICT is the longest  trial of CPAP specifically in older people with sleep apnoea. It provides evidence to support the application of NICE recommendations in this population, which was previously uncertain. On average, the people included in this trial had mild sleep apnoea, but it was still serious enough that they had sought treatment for it.

PREDICT found that CPAP was cost-effective but to a lesser extent than was calculated for the 2008 NICE guidance. This may be a difference between older and younger population or might be because many of the studies in NICE’s analysis compared CPAP against “do nothing”, whereas PREDICT compares it against best supportive care, which provided advice and information.

Symptoms improved more the longer CPAP was used each night, suggesting a need to ensure that patients comply and use the device for long enough each night.

Citation

McMillan A, Bratton DJ, Faria R et al. A multicentre randomised controlled trial and economic evaluation of continuous positive airway pressure for the treatment of obstructive sleep apnoea syndrome in older people: PREDICT. Health Technol Assess 2015; 19(4).

This project was funded by the National Institute for Health Research HTA Programme (project number 08/56/02).

Bibliography

Clinical Knowledge Summaries. Obstructive sleep apnoea syndrome. London: National Institute for Health and Care Excellence; updated 2015.

Johns MW. A New Method For Measuring Daytime Sleepiness: The Epworth Sleepiness Scale. Sleep 1991; 14(6):540-5.

NHS Choices. Obstructive sleep apnoea. London: Department of Health; updated 2015.

NICE.  Continuous positive airway pressure for the treatment of obstructive sleep apnoea/hypopnoea syndrome. TA139. London: National Institute for Health and Care Excellence; 2008.

Why was this study needed?

Obstructive sleep apnoea is a fairly common condition, affecting 2-4% of middle-aged people and up to 20% of older people. The muscle and soft tissue in the throat relax during sleep, temporarily blocking the supply of air to the lungs. This disrupts the peron’s sleep – they wake up or sleep lighter during the night – causing sleepiness in the daytime. This can increase their risk of road traffic accidents from falling asleep at the wheel. One treatment - continuous positive airway pressure (CPAP) – involves wearing a face mask that continuously pumps a small amount of pressurised air into the throat to prevent it collapsing during the night. A 2008 meta-analysis for NICE found that CPAP reduced daytime sleepiness and was cost effective in middle-aged people. However, the evidence was less clear in older people. The NIHR funded this study to measure the clinical and cost effectiveness of CPAP in older adults, aged 65 or more, with newly diagnosed obstructive sleep apnoea.

What did this study do?

The PREDICT randomised controlled trial (RCT) randomly allocated 278 people aged 65 and over, with obstructive sleep apnoea syndrome to receive either “best supportive care” only, or best supportive care with CPAP. Best supportive care was defined as advice on minimising daytime sleepiness through lifestyle changes – such as improving sleep hygiene, napping, caffeine or losing weight if appropriate. The RCT took place in 12 NHS sleep clinics across the UK. Sleep clinic staff measuring sleep outcomes were unaware of the treatment participants had received, reducing potential bias in their assessments. Data analyses were pre-specified, reducing the risk of bias at this stage.

What did it find?

  • 231 participants were assessed at 3 and 12 months and included in the analysis. After three months, CPAP with best supportive care improved self-reported sleepiness by an average of 3.8 points (from 11.5 to 7.7) on a 0 to 24 sleep scale. This was a slightly larger improvement than best supportive care only, average improvement 2.0 points (from 11.4 to 9.8). A score of 11 or above indicates possible sleep apnoea, whereas a score of 10 or below is considered normal. CPAP remained the marginally better treatment by 2.0 points (95% confidence interval [CI]  2.8 to  1.2) after 12 months.
  • The average annual cost was comparable between CPAP (£1,363) and best supportive care (£1,389). In the economic analysis, CPAP appeared to be a cost-effective alternative to BSC alone. CPAP decreased costs by a small amount and improved health outcomes. However, the differences in costs and health outcomes between the treatment groups were small and uncertain. The probability that CPAP would be cost-effective at the NHS threshold of £20,000 per QALY gained was 61%, using the EQ-5D scale to measure health related quality of life.
  • General and disease-specific quality of life improved more in those receiving CPAP. Both groups experienced improvements in daily functions and reduced night-time urination. There was no change in incidence of road traffic accidents.

What does current guidance say on this issue?

2008 NICE guidelines recommend that people with moderate or severe obstructive sleep apnoea are offered CPAP if their sleep apnoea affects their daily life – such as falling asleep at work – and if other treatments or lifestyle changes have not been successful.

What are the implications?

PREDICT is the longest  trial of CPAP specifically in older people with sleep apnoea. It provides evidence to support the application of NICE recommendations in this population, which was previously uncertain. On average, the people included in this trial had mild sleep apnoea, but it was still serious enough that they had sought treatment for it.

PREDICT found that CPAP was cost-effective but to a lesser extent than was calculated for the 2008 NICE guidance. This may be a difference between older and younger population or might be because many of the studies in NICE’s analysis compared CPAP against “do nothing”, whereas PREDICT compares it against best supportive care, which provided advice and information.

Symptoms improved more the longer CPAP was used each night, suggesting a need to ensure that patients comply and use the device for long enough each night.

Citation

McMillan A, Bratton DJ, Faria R et al. A multicentre randomised controlled trial and economic evaluation of continuous positive airway pressure for the treatment of obstructive sleep apnoea syndrome in older people: PREDICT. Health Technol Assess 2015; 19(4).

This project was funded by the National Institute for Health Research HTA Programme (project number 08/56/02).

Bibliography

Clinical Knowledge Summaries. Obstructive sleep apnoea syndrome. London: National Institute for Health and Care Excellence; updated 2015.

Johns MW. A New Method For Measuring Daytime Sleepiness: The Epworth Sleepiness Scale. Sleep 1991; 14(6):540-5.

NHS Choices. Obstructive sleep apnoea. London: Department of Health; updated 2015.

NICE.  Continuous positive airway pressure for the treatment of obstructive sleep apnoea/hypopnoea syndrome. TA139. London: National Institute for Health and Care Excellence; 2008.

A multicentre randomised controlled trial and economic evaluation of continuous positive airway pressure for the treatment of obstructive sleep apnoea syndrome in older people: PREDICT

Published on 13 June 2015

McMillan, A.,Bratton, D. J.,Faria, R.,Laskawiec-Szkonter, M.,Griffin, S.,Davies, R. J.,Nunn, A. J.,Stradling, J. R.,Riha, R. L.,Morrell, M. J.

Health Technol Assess Volume 19 , 2015

BACKGROUND: The therapeutic and economic benefits of continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnoea syndrome (OSAS) have been established in middle-aged people. In older people there is a lack of evidence. OBJECTIVE: To determine the clinical efficacy of CPAP in older people with OSAS and to establish its cost-effectiveness. DESIGN: A randomised, parallel, investigator-blinded multicentre trial with within-trial and model-based cost-effectiveness analysis. METHODS: Two hundred and seventy-eight patients, aged >/= 65 years with newly diagnosed OSAS [defined as oxygen desaturation index at >/= 4% desaturation threshold level for > 7.5 events/hour and Epworth Sleepiness Scale (ESS) score of >/= 9] recruited from 14 hospital-based sleep services across the UK. INTERVENTIONS: CPAP with best supportive care (BSC) or BSC alone. Autotitrating CPAP was initiated using standard clinical practice. BSC was structured advice on minimising sleepiness. COPRIMARY OUTCOMES: Subjective sleepiness at 3 months, as measured by the ESS (ESS mean score: months 3 and 4) and cost-effectiveness over 12 months, as measured in quality-adjusted life-years (QALYs) calculated using the European Quality of Life-5 Dimensions (EQ-5D) and health-care resource use, information on which was collected monthly from patient diaries. SECONDARY OUTCOMES: Subjective sleepiness at 12 months (ESS mean score: months 10, 11 and 12) and objective sleepiness, disease-specific and generic quality of life, mood, functionality, nocturia, mobility, accidents, cognitive function, cardiovascular risk factors and events at 3 and 12 months. RESULTS: Two hundred and seventy-eight patients were randomised to CPAP (n = 140) or BSC (n = 138) over 27 months and 231 (83%) patients completed the trial. Baseline ESS score was similar in both groups [mean (standard deviation; SD) CPAP 11.5 (3.3), BSC 11.4 (4.2)]; groups were well balanced for other characteristics. The mean (SD) in ESS score at 3 months was -3.8 (0.4) in the CPAP group and -1.6 (0.3) in the BSC group. The adjusted treatment effect of CPAP compared with BSC was -2.1 points [95% confidence interval (CI) -3.0 to -1.3 points; p < 0.001]. At 12 months the effect was -2.0 points (95% CI -2.8 to -1.2 points; p < 0.001). The effect was greater in patients with increased CPAP use or higher baseline ESS score. The number of QALYs calculated using the EQ-5D was marginally (0.005) higher with CPAP than with BSC (95% CI -0.034 to 0.044). The average cost per patient was pound1363 (95% CI pound1121 to pound1606) for those allocated to CPAP and pound1389 (95% CI pound1116 to pound1662) for those allocated to BSC. On average, costs were lower in the CPAP group (mean - pound35; 95% CI - pound390 to pound321). The probability that CPAP was cost-effective at thresholds conventionally used by the NHS ( pound20,000 per QALY gained) was 0.61. QALYs calculated using the Short Form questionnaire-6 Dimensions were 0.018 higher in the CPAP group (95% CI 0.003 to 0.034 QALYs) and the probability that CPAP was cost-effective was 0.96. CPAP decreased objective sleepiness (p = 0.02), increased mobility (p = 0.03) and reduced total and low-density lipoprotein cholesterol (p = 0.05, p = 0.04, respectively) at 3 months but not at 12 months. In the BSC group, there was a fall in systolic blood pressure of 3.7 mmHg at 12 months, which was not seen in the CPAP group (p = 0.04). Mood, functionality, nocturia, accidents, cognitive function and cardiovascular events were unchanged. There were no medically significant harms attributable to CPAP. CONCLUSION: In older people with OSAS, CPAP reduces sleepiness and is marginally more cost-effective than BSC over 12 months. Further work is required in the identification of potential biomarkers of sleepiness and those patients at increased risk of cognitive impairment. Early detection of which could be used to inform the clinician when in the disease cycle treatment is needed to avert central nervous system sequelae and to assist patients decision-making regarding treatment and compliance. Treatment adherence is also a challenge in clinical trials generally, and adherence to CPAP therapy in particular is a recognised concern in both research studies and clinical practice. Suggested research priorities would include a focus on optimisation of CPAP delivery or support and embracing the technological advances currently available. Finally, the improvements in quality of life in trials do not appear to reflect the dramatic changes noted in clinical practice. There should be a greater focus on patient centred outcomes which would better capture the symptomatic improvement with CPAP treatment and translate these improvements into outcomes which could be used in health economic analysis. TRIAL REGISTRATION: Current Controlled Trials ISRCTN90464927. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 40. See the NIHR Journals Library website for further project information.

A continuous positive airway pressure device is a mask covering either the nose or the nose and mouth that pumps a small amount of pressurised air into the throat to keep it open during sleep. Wearing a CPAP mask can feel strange and uncomfortable. Some people experience side effects such as sore skin around the mask, dry mouth or sinus problems. Consequently some people either do not use the device enough or do not use it at all, which can reduce its effectiveness in treating their obstructive sleep apnoea. NICE acknowledges this issue and recommends follow-up with patients specifically to ensure that they use the device.

Author commentary

This was a large trial in an area that is under-researched.  The focus on older people was welcome and the study usefully included information on co-morbidity, which is often lacking clinical guidelines.  The trial clearly showed that in older patients with these sleep and breathing problems, CPAP treatment reduces symptoms of daytime sleepiness, as it does in middle-aged populations. Future research should focus on how best to optimize CPAP delivery, and emphasis should be placed on raising awareness of this condition, a treatable sleep disorder in older people. We also need to investigate the possible role of obstructive sleep apnoea in cognitive decline.

Mary J Morrell, PhD, Professor of Sleep and Respiratory Physiology, National Heart and Lung Institute, Imperial College London