Continuous positive airway pressure appears to improve glycaemic control in patients with obstructive sleep apnoea and poorly controlled type 2 diabetes, say Spanish researchers.
Their study, published in the American Journal of Respiratory and Critical Care Medicine, is believed to be the first randomised controlled trial of its kind.
“Early identification of obstructive sleep apnoea in patients with type 2 diabetes… could reduce the cardiovascular disease risk”
Senior study author Francisco Garcia-Rio, professor of medicine at Autonoma University of Madrid, said the research advanced understanding of the relationship between “two major public health problems”, which previous studies had indicated were related.
The researchers studied results from 50 patients with both sleep apnoea and sub-optimally controlled diabetes, who either received CPAP or usual treatment.
Participants, who ranged in age from 18 to 80, did not change diabetes medications – unless clinically necessary – their diet or level of physical activity during the trial.
In addition to measuring glucose control, researchers measured changes in insulin sensitivity and resistance, inflammatory proteins and other biomarkers.
Researchers found that those using CPAP showed a statistically significant decrease in HbA1c levels at six months – though the decrease at three months was not significant.
Sleep apnoea treatment may aid glycaemic control
They also found improvement in insulin sensitivity at three and six months among CPAP patients, and a decrease in insulin resistance at six months.
In addition, CPAP participants experienced lower levels of the inflammatory molecules IL-1β and IL-6 and higher levels of the hormone adiponectin, an important glucose regulator.
Dr Garcia-Rio said: “Early identification of obstructive sleep apnoea in patients with type 2 diabetes, and assessment for metabolic abnormalities in those with obstructive sleep apnoea could reduce the cardiovascular disease risk of patients with these chronic diseases.”
Researchers said they believed the results were widely applicable, given that study participants were referred from diabetes units or GPs and, therefore, reflected standard clinical practice.
However, they acknowledged that the study was small in size and lacked a genuine placebo arm.