O053 Cardio-metabolic Health Effects of CPAP Treatment for Sleep Apnoea during Weight Loss: A Randomised Controlled Pilot Trial.

INTRODUCTION: This study assessed whether the addition of CPAP during weight loss would enhance cardiometabolic health improvements in patients with obesity and OSA. METHODS: Patients with overweight or obesity, pre-diabetes and moderate-severe OSA were randomised to receive CPAP therapy with a weight loss programme (CPAP+WL) or a weight loss programme alone (WL alone). Primary outcome: 2-hour glucose assessed by OGTT. Trial registration: ANZCTRN 12617000823370. RESULTS: 17 patients completed 3-month follow-up assessments (8 CPAP+WL and 9 WL alone). Mean CPAP compliance was 5.29 hrs/night. Participants lost ~12 kg which reduced OSA severity by ~45%. The primary analysis showed no between group differences for any of the assessed outcomes. Despite this, most outcomes improved with weight loss including insulin sensitivity (.000965 units, p=.008), wake diastolic BP (-4.3mmHg, p=.03), sleep systolic BP (-16.2 mmHg, p=.0003), sleep diastolic BP (-9.8 mmHg, p=0.02), and sleepiness (Epworth Sleepiness Score -3.2, p=.0003). Two-hour glucose levels did not improve (p=0.33), but the glucose area under the curve (AUC) was reduced (-230 units, p=.009). In addition, total (-0.86mmol/L, p=0.006) and LDL cholesterol (-0.58mmol/L, p=0.007), triglycerides (-0.75mmol/L, p=0.004), fat mass (-7.6kg, p<.0001) and abdominal fat (-310cm3, p<.0001) were all reduced. CONCLUSIONS: We did not establish any cardio-metabolic benefit from CPAP therapy during weight loss. In contrast, weight loss had a robust positive effect on cardio-metabolic health. The magnitude of weight loss improvements far exceeded those from trials assessing the impact of CPAP alone, suggesting that weight loss should be the primary focus of treatment for patients with OSA and obesity.