Continuous positive airway pressure in older people with obstructive sleep apnoea syndrome (PREDICT): a 12-month, multicentre, randomised trial

Background: The therapeutic and economic benefits of continuous positive airway pressure (CPAP) for moderate to severe obstructive sleep apnoea (OSA) syndrome have been established in middle-aged people; however, the benefits in older people are unknown. This trial was designed to address this evidence gap.

Methods: This 12-month, multicentre, randomised trial enrolled patients across 14 National Health Service sleep centres in the UK. Consecutive patients aged 65 years or older with newly diagnosed OSA syndrome were eligible to join the trial. Patients were randomly assigned (1:1) into parallel groups to receive either CPAP with best supportive care (BSC) or BSC alone for 12 months. Randomisation was done by the Medical Research Council Clinical Trials Unit with computer-generated randomisation. The main investigator at each centre was masked to the trial randomisation. Coprimary endpoints were Epworth sleepiness score (ESS) at 3 months and cost-effectiveness over the 12-month trial period. Secondary outcomes were subjective sleepiness at 12 months, plus objective sleepiness, quality of life, mood, functionality, nocturia, mobility, accidents, cognitive function, and cardiovascular risk factors and events at 3 months and 12 months. The analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN90464927.

Findings: Between Feb 24, 2010, and May 30, 2012, 278 patients were randomly assigned to the trial, of whom 231 (83%) completed the trial. 140 patients were allocated to and received CPAP plus BSC and 138 were allocated to and received BSC only. CPAP reduced ESS by 2·1 points (95% CI -3·0 to -1·3; p<0·0001) at 3 months for 124 (89%) of 140 patients compared with 124 (90%) of 138 patients given BSC, and by 2·0 points (-2·8 to -1·2; p<0·0001) at 12 months for 116 patients compared with 122 patients given BSC. The effect was greater in patients with higher CPAP usage or higher baseline ESS. Quality-adjusted life-years were similar between the groups (treatment effect 0·01 (95% CI -0·03 to 0·04; p=0·787) and health-care costs were marginally reduced with CPAP (-£35, -390 to 321; p=0·847). CPAP improved objective sleepiness (p=0·024), mobility (p=0·029), total cholesterol (p=0·048), and LDL cholesterol (p=0·042) at 3 months, but these were not sustained at 12 months. Measures of mood, functionality, nocturia, accidents, cognitive function, and cardiovascular events remained unchanged. Systolic blood pressure fell in the BSC group. 37 serious adverse events occurred in the CPAP group, and 22 in BSC group; all were independently classified as being unrelated to the trial and no significant harm was attributed to CPAP use.

Interpretation: In older people with OSA syndrome, CPAP reduces sleepiness and is marginally more cost effective over 12 months than is BSC alone. On the basis of these results, we recommend that CPAP treatment should be offered routinely to older patients with OSA syndrome.

Funding: National Institute of Health Research (NIHR) Health Technology Assessment, NIHR Respiratory Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College London.