Author Interviews, Diabetes, Pulmonary Disease, Sleep Disorders / 15.03.2016
CPAP Benefits Sleep and Blood Pressure in Diabetics, But Not Glucose Control
MedicalResearch.com Interview with:
Jonathan Shaw MD, FRACP, FRCP (UK), FAAHMS
Associate Professor
Domain Head, Population Health Research
Baker IDI Heart and Diabetes Institute
Melbourne VIC 3004
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Shaw: Over the last decade or so, there has been a lot of research connecting obstructive sleep apnoea with type 2 diabetes. They co-exist very frequently in the same individual, they are both much more common in overweight and obese people than in people of healthy weights, both improve with weight loss, and both are associated with other conditions such as hypertension and heart disease. In addition, there has been evidence that some of the key abnormalities occurring in sleep apnoea (in particular, fragmented sleep and intermittent low oxygen levels) may have a direct effect on glucose metabolism, and increase blood sugar levels. This led many people to suspect that untreated sleep apnoea might be one reason that type 2 diabetes is hard to control, and that treating sleep apnoea in people with type 2 diabetes would improve their blood sugar control.
We, therefore, undertook a large trial among people with type 2 diabetes, and previously unrecognised sleep apnoea, in which participants were randomised to either a group receiving specific treatment for sleep apnoea (continuous positive airways pressure, or CPAP, therapy at night) or to a control group.
Over the six months of the trial, we saw no benefit of CPAP therapy in regard to blood sugar control (as measured by HbA1c). Even when we looked at sub-groups with worse blood sugar control at the start or worse sleep apnoea or who did the best in terms of using CPAP every night, there was still no sign of benefit on blood sugar control. We did, however, see some other benefits of CPAP therapy, with less daytime sleepiness, improvements in quality of life and lower diastolic blood pressure.
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