Treating sleep apnea after weight loss to maintain cardio-metabolic health in the obese with pre-diabetes - A Randomised Controlled Trial

weight loss

This randomised controlled trial targets obese patients with pre-diabetes and persistent obstructive sleep apnea despite achieving rapid weight loss and will test whether continuous positive airway pressure improves insulin sensitivity after 10 months weight loss maintenance.

Program type: Honours/Masters/PhD

Research Group: Sleep and Circadian Research Group

Supervisors: A/Prof Craig Phillips, Dr Camilla Hoyos and Dr Elizabeth Cayanan

Synopsis: Many weight loss interventions work in the short term, often inducing dramatic improvements in cardio-metabolic health. However these health improvements are shortlived and people eventually suffer “rebound” where weight is regained and cardiometabolic health declines. We think that this might be exacerbated by comorbid obstructive sleep apnea (OSA). We hypothesise that after successful weight loss in obese people with OSA and pre-diabetes, treatment of persistent OSA will better sustain insulin sensitivity (a strong prognostic marker of diabetes risk) and other cardio-metabolic health measures (including abdominal fat loss) at one year compared to not treating OSA.

Research Plan: This hypothesis will be tested in 2 groups of obese patients with prediabetes and co-morbid OSA using a 3-month randomised controlled trial (RCT) design. At the beginning of the trial, patients will be randomised to intensive weight loss therapy and continuous positive airway pressure (CPAP) (intervention group) or intensive weight loss therapy only. The primary outcome will be the difference in insulin sensitivity between CPAP and non-CPAP treated groups at 3 months. Our effective weight loss and maintenance program has already provided preliminary data supporting our hypothesis. Our interdisciplinary team are world leaders in obesity and OSA RCT’s with expertise in assessing major health outcomes including insulin sensitivity and body fat.

Significance: Despite their short-term effectiveness, weight loss strategies have not been shown to sustain cardio-metabolic health in the longer-term beyond 6 months. The results of this study will help determine the role of OSA treatment in insulin sensitivity and determine whether it enhances the efficacy of weight loss therapy. It will guide future interdisciplinary clinical practice including prioritising treatment resources to patients with obesity and OSA who are attempting to improve cardio-metabolic health by losing weight and keeping it off.

Candidate: We anticipate that the successful candidate will have completed an undergraduate degree and will have experience/interest in dietetics and/or exercise science/ exercise physiology.

Contact: Elizabeth Cayanan elizabeth.cayanan@sydney.edu.au.