Statistical analysis plan for continuous positive airway pressure plus mandibular advancement therapy (PAPMAT): an adaptive randomised crossover trial comparing the benefits and costs of combining two established treatments for obstructive sleep apnoea.

BACKGROUND: Obstructive sleep apnoea is caused by closure of the upper airway during sleep due to excessive muscle relaxation. It is treated with continuous positive airway pressure (CPAP), a machine connected to a mask worn by a patient during sleep, which generates pressure to keep the throat open. CPAP is highly effective, but often not tolerated, sometimes due to the required pressure of the machine. Mandibular advancement devices advance the lower jaw, increasing airway space. Using such a device may open the airway enough to allow CPAP pressure to be reduced, resulting in more patients being able to tolerate using the CPAP machine.

METHODS/DESIGN: The PAPMAT trial is a multicentre, randomised controlled crossover trial. It will measure CPAP machine adherence for participants with obstructive sleep apnoea, comparing their adherence when using a CPAP machine alone to using a CPAP machine in conjunction with a mandibular advancement device. The sample size will be re-estimated after at least 50% of participants have completed follow-up. This document is the statistical analysis plan, which gives details of the planned analysis, including the sample size re-estimation.

TRIAL REGISTRATION: ISRCTN 33966032. Registered 18th February 2022.