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02 September 2010
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| [ Print-friendly version ] |
| Positive airway pressure in older people: A randomised controlled trial |
| ISRCTN | ISRCTN90464927 |
| ClinicalTrials.gov identifier | |
| Public title | Positive airway pressure in older people: A randomised controlled trial |
| Scientific title | A randomised controlled trial of continuous positive airway pressure treatment in older people with obstructive sleep apnoea/ hypopnoea syndrome |
| Acronym | PREDICT |
| Serial number at source | HTA 08/56/02 |
| Study hypothesis |
Obstructive sleep apnoea hypopnoea syndrome (OSAHS) is the name given to difficulty in breathing during sleep due to blockage of the airway behind the tongue. It causes profound daytime sleepiness, high blood pressure, an increased risk of heart attack/ stroke and possibly memory problems. OSAHS is the third most common respiratory disorder, after asthma and chronic obstructive pulmonary disease, affecting 2 - 4% of middle aged people. In older people prevalence is almost 10 times greater, with up to 20% of older people having OSAHS.
OSAHS can be treated with continuous positive airway pressure (CPAP). A recent report by the National Institute for Clinical Excellence concluded that CPAP is an extremely cost effective treatment for OSAHS in middle-aged people. Unfortunately the beneficial effects of CPAP cannot be presumed to be replicated in older people because the causes and consequences of the disease change with age. Very little information is available for doctors and health care professionals regarding the best way to treat OSAHS in older people. This study will measure the effect of treating OSAHS on sleepiness and other health related factors, such as risk factors for heart disease and memory function in patients over 65 years old. This information will be compared to that collected in another group of patients in whom the OSAHS will be treated with a Best Supportive Care Package (control). Before patients agree to take part in the study it will be explained that they may be allocated to receive either CPAP and Best Supportive Care or Best Supportive Care only; this 'randomisation' is the best way to test the effectiveness of a treatment. Each group will be monitored for 12 months. Particular attention will be paid to the use of health care facilities. Comparison of the data from the two groups will show whether CPAP effectively treats older people with OSAHS. It will also reveal the cost efficiency of CPAP treatment in older people. The UK population is ageing, thereby increasing the burden of disease. One of the best ways to reduce these costs is to maintain the independence of older people. Treating OSAHS appropriately in older people is a potentially important way of reducing the dependency of ageing, which will in turn benefit both individual patients and economic burden of disease within the UK. More details can be found at http://www.hta.ac.uk/project/1844 Protocol can be found at http://www.hta.ac.uk/protocols/200800560002.pdf As of 07/04/2010 this record was updated; all changes can be found under the relevant field with the above update date. At this time, the target number of participants was updated from 250 to 278. |
| Ethics approval | Added 07/04/2010: Brompton, Harefield and NHLI Research Ethics Committee approved on the 22nd May 2009 (ref: 09/H0708/33) |
| Study design | Randomised controlled trial |
| Countries of recruitment | United Kingdom |
| Disease/condition/study domain | Sleep apnoea |
| Participants - inclusion criteria |
Current inclusion criteria as of 07/04/2010:
1. Aged greater than 65 years, either sex 2. A clinical diagnosis of OSAHS: more than/equal to 4% oxygen desaturation index greater than 7.5 events/hour and an Epworth sleepiness scale more than/equal to 9 3. Ability to give written informed consent Previous inclusion criteria at time of registration: 1. Both males and females, aged greater than 65 years 2. Apnoea hypopnoea index greater than or equal to 15 events/hour of sleep on multi-channel sleep study, and at least two symptoms of excessive daytime sleepiness or Epworth sleepiness scale greater than or equal to 11 3. Written informed consent |
| Participants - exclusion criteria |
1. Previous exposure to nasal CPAP therapy
2. Arterial oxygen saturation less than 93% 3. Forced expiratory volume in one second (FEV1) less than 65% predicted 4. Substantial problems with sleepiness driving (in those who are still driving); currently using Heavy Goods Vehicle (HGV) or Public Service Vehicle (PSV) driving licence (where applicable) 5. Shift work 6. Inability to give informed consent or comply with the protocol 7. Irreversible visual impairment |
| Anticipated start date | 01/02/2009 |
| Anticipated end date | 31/05/2012 |
| Status of trial | Ongoing |
| Patient information material | Not available in web format, please use the contact details below to request a patient information sheet |
| Target number of participants | 278 |
| Interventions |
Treatment (Continuous positive airway pressure) limb
Obstructive sleep apnoea will be diagnosed from a diagnostic overnight polysomnographic sleep study. After trial entry, subjects assigned to CPAP therapy will be started on self-adjusting nasal CPAP therapy (AutoSet®, ResMed Plc). This therapy automatically adjusts airway pressure to be sufficient to prevent snoring and sleep apnoea without being excessive. The initiation of this therapy will be in keeping with the recruiting centres normal clinical practice (and minimisation by centre at trial entry will ensure that subjects with slightly varying CPAP initiation protocols are evenly distributed between the trial groups). At months 3 and 12 of trial follow-up the stored memory of the CPAP machines will be interrogated to define treatment efficiency over multiple nights. This will define how well sleep apnoea has been controlled over time in the intervention group. Overnight arterial pulse oximetry recording will be performed to quantify sleep apnoea control on one night in both trial groups. The active treatment limb will also receive the best supportive care package. Control limb (Best supportive care only) Best supportive care will consist of: 1. Advice on minimising daytime sleepiness through sleep hygiene and advice about using the nap/caffeine assaults management strategy 2. Advice on weight loss strategies 3. A general medical review to confirm optimal healthcare for any co-morbid conditions 4. Cardiovascular risk assessment with intervention (co-ordinated through the General Practitioner) to minimise vascular risk. Consistent with national guidelines. Total duration of interventions and follow-up: 12 months |
| Primary outcome measure(s) |
The following will be measured throughout the whole of the 12-month trial period:
1. Subjective sleepiness: average weekly Epworth Sleepiness Scale (ESS) 2. Health economic analysis: measured from health care utilisation and cost utility analysis using the EQ-5D |
| Secondary outcome measure(s) |
Current secondary outcome measures as of 07/04/2010:
The following will be measured throughout the whole of the 12-month trial period: 1. Objective sleepiness: Oxford Sleep Resistance Test (OSLER) maintenance of wakefulness test (x 2 morning tests) 2. Self reported health status (quality of life and mood): 36-item Short Form questionnaire (SF-36), and Sleep Apnoea Quality of Life Index (SAQLI; a disease specific sleep apnoea questionnaire which includes CPAP side effects), Hospital Anxiety and Depression Scale (HADS) 3. Functional index of activities of daily living: Townsend Disability Scale (TDS) 4. Frequency of nocturia: Self reported using the patient [monthly] diary 5. Mobility: Timed to up and go test 6. Accidents: Including self-reported road accidents and domestic accidents 7. Cognitive function: Mini-mental state, Trail making B time, the Digit Symbol Substitution test, simple and four-choice reaction time 8. Cardiovascular Risk Index: Change in combined stroke and myocardial infarction risk measured by the Framingham vascular risk index, which includes office blood pressure, cholesterol, smoking status, hyperglycaemia 9. Adverse cardiovascular events: Myocardial infarction, stroke, transient ischemic attack, new angina, new atrial fibrillation, new peripheral vascular disease Previous secondary outcome measures at time of registration: The following will be measured throughout the whole of the 12-month trial period: 1. Objective sleepiness: measured using the maintenance of wakefulness test of the Oxford sleep resistance test (OSLER) 2. Self-reported health status (quality of life): the 36-item Short Form health survey (SF-36), CASP-19, the Short Sleep Apnea Quality of Life Index (SAQLI) questionnaire (which includes CPAP side effects) 3. Accidents, including road accidents 4. Change in combined stroke and myocardial infarction risk: measured by the Framingham Index 5. Individual components of the Framingham vascular risk index; blood pressure, cholesterol, smoking, glycaemia 6. Myocardial infarction/ stroke/ vascular event rate, left ventricular hypertrophy (ECG) 7. Cognitive function 8. Systemic inflammatory status 9. Functional index of activities of daily living (Townsend disability scale) |
| Sources of funding | NIHR Health Technology Assessment Programme - HTA (UK) |
| Trial website | |
| Publications | |
| Contact name | Mrs Magda Laskawiec |
| Address |
Oxford Centre for Respiratory Medicine
Respiratory Trials Unit Churcihll Hospital Old Road Headington |
| City/town | Oxford |
| Zip/Postcode | OX3 7LJ |
| Country | United Kingdom |
| Sponsor | University of Oxford (UK) |
| Address |
Clinical Trials and Research Governance (CTRG)
Manor House John Radcliffe Hospital Headington |
| City/town | Oxford |
| Zip/Postcode | OX3 9DU |
| Country | United Kingdom |
| Sponsor website: | http://www.ox.ac.uk |
| Date applied | 11/06/2008 |
| Last edited | 07/04/2010 |
| Date ISRCTN assigned | 18/06/2008 |
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