Sleep apnea treatment improves glycemic control in patients with type 2 diabetes

What is it about?

In this randomized controlled trial, researchers in Spain studied results from 50 patients with both obstructive sleep apnea (OSA) and suboptimally controlled Type 2 diabetes who were assigned to continuous positive airway pressure (CPAP) intervention or control. Participants, who ranged in age from 18 to 80, did not change diabetes medications during the trial unless medically necessary, nor were they expected to change their diets or level of physical activity. In addition to measuring glucose control, researchers measured changes in insulin sensitivity and resistance, inflammatory proteins and other biomarkers that may be associated with Type 2 diabetes glycemic control. Researchers found that those using CPAP showed a statistically significant: • Decrease in glycated hemoglobin (HbA1c) levels at 6 months. (The decrease at 3 months was not statistically significant.) • Improvement in insulin sensitivity at 3 and 6 months. • Decrease in insulin resistance at 6 months. Researchers also found 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.

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Why is it important?

OSA is a public health problem of the first order, due to its high prevalence and marked morbidity and mortality, having been linked to traffic accidents, cardiovascular complications and, more recently, neoplastic diseases. Diabetes mellitus is a global epidemic. There are currently 382 million diabetics worldwide, a figure which is estimated to reach 592 million in 2035. Type 2 diabetes, which accounts for 90%–95% of all diabetes cases, is a complex metabolic disorder in which the interaction of genetic and environmental factors causes a deficiency in both insulin secretion and insulin sensitivity. A bidirectional association between OSA and Type 2 diabetes is supported by several epidemiological studies as well as possible pathogenic mechanisms that make it biologically plausible. In Type 2 diabetic patients, a prevalence of OSA of up to 60% has been reported. At the same time, the prevalence of Type 2 diabetes in patients with OSA ranges from 15% to 30%. Authors noted that previous studies reported a 1 percent decrease in HbA1c levels was associated with 15-20 percent decrease in major cardiovascular disease events and a 37 percent decrease in microvascular complications from diabetes. If the association proves true, the authors said the 0.4 percent reduction in HbA1c in their study might translate into a 6-8 percent decrease in cardiovascular disease risk and a 15 percent reduction in microvascular complication risk. They added that their study also found those in the CPAP group experienced a significant reduction in LDL cholesterol, an established risk factor for cardiovascular disease. Early identification of obstructive sleep apnea in patients with type 2 diabetes, and assessment for metabolic abnormalities in those with obstructive sleep apnea could reduce the cardiovascular disease risk of patients with these chronic diseases.