The Sleeping Well Trial: enhancing the effectiveness of continuous positive airway pressure (CPAP) treatment with a weight management program for overweight adults

To address aim 1) Primary outcome (weight) as measured during each month during the control and intervention periods of the stepped wedge design will be compared between periods. The main effect of the intervention will be examined using a multilevel, mixed effects, linear mixed model analysis approach. Fixed effects will be included in this model for “time” and “intervention”, while a random effect will be included for the effect of “participant”. To address aim 2) We will examine the association between lifestyle intervention commencement month and weight at 12 month follow-up (adjusted for baseline weight). This analysis will treat "lifestyle intervention commencement month" as a continuous variable and examine both a linear and quadratic relationship with the outcome. CPAP treatment: All CPAP implementation will be provided centrally for all patients by Air Liquide Healthcare. Patients will undergo mask fitting and education regarding sleep apnoea and CPAP use by staff at Air Liquide. Patients will initially be commenced on Autotitrating CPAP using a Resmed S9 CPAP machine. After 1 week of treatment, patients will be switched to fixed pressure CPAP based on the 95th centile pressure determined during the autotitration week. Routine equipment troubleshooting will be provided by Air Liquide, in conjunction with the patient’s treating physician. Patients will undergo routine CPAP care co-ordinated by their physician. All decisions regarding any treatment changes will be made by the treating physician. Participants are required to use their CPAP devices regularly for 12 months period (beginning from consent date). Lifestyle Intervention: All participants will be exposed to the 6-month weight management program. The wait list time for starting treatment will differ with subjects randomised to wait 1,2,3,4,5 or 6 months before they commence. The Intervention is a dietitian delivered face to face intervention comprising of a 1 hour initial appointment followed up by monthly 30 minute consultations. Dietary energy will be reduced using a tailored approach with a 12 week active weight loss phase followed by a 12 week transfer to weight maintenance phase the duration of each phase will be dependant on how much weight each participant has to lose and their success, which is monitored monthly by body weight. The use of an App to extend the reach of the face to face sessions will be utilised. The App allows the participant to connect virtually with their dietitian to report hurdles, feelings or mood that may affect their progress towards their goals. The dietitian can communicate via a pre-defined pathway of text messages which are sent to the participant to motivate them to continue to meet their 'small steps'. Activity is encouraged with 3 x 30 minutes per week of light/ moderate physical activity. Compliance is measured for activity via a wrist worn monitor (Fitbit) which records minute by minute activity on a website which the participant consents to the research team being able to access. Dietary recording is used to monitor compliance with meal plans and agreed nutrient goals. Compliance with CPAP treatment is recorded individually and is inbuilt into each CPAP machine, as minutes per day that it is used.