Spotlight on diabetes and sleep disorders

A review, published Aug. 16 by Diabetologia, analyzed studies of sleep disorders among patients with type 2 diabetes, finding that insomnia, obstructive sleep apnea, and restless leg syndrome were all more prevalent in this group than in the general population (39% vs. 10%, 55% to 86% vs. 3% to 7%, and 8% to 45% vs. 5% to 10%, respectively). The review did not identify any prevalence rates for circadian rhythm sleep–wake disorders, central disorders of hypersomnolence, or parasomnias among diabetes patients. Included studies did show that sleep disorders negatively affected diabetes-related health outcomes, particularly glycemic control. The review also looked at therapies for sleep disorders, including medications, finding few randomized controlled trials that investigated the effect of treating sleep disorders in people with type 2 diabetes. “Conventional therapies such as weight loss, sleep education and cognitive behavioural therapy seem to be effective in improving sleep and health outcomes in people with type 2 diabetes,” said the authors, who called for future studies to explore the impact of individual and overlapping sleep disorders, as well as treatments for them in patients with type 2 diabetes.

Sleep disorders appeared to be associated with higher mortality among people with impaired glucose tolerance, according to a study published Aug. 5 by BMJ Open Diabetes Research & Care. It included 8,795 patients from the National Health and Nutrition Examination Survey. None were taking diabetes medications at baseline, and an oral glucose tolerance test found that 76.8% had normal glucose tolerance, 16.7% had impaired glucose tolerance, and 6.5% had diabetes. Patients with impaired glucose tolerance and a sleep disorder had more than double the mortality risk of patients with normal tolerance and no sleep disorders (adjusted hazard ratio, 2.03; 95% CI, 1.24 to 3.34). Diabetes patients with and without sleep disorders also showed increased mortality risks. The results were consistent when the marker of a sleep problem was sleep duration of less than seven hours. “Careful monitoring and management of sleep quality and quantity might be beneficial” for patients with impaired glucose tolerance, the authors said.

Finally, the use of continuous positive airway pressure (CPAP) in patients with type 2 diabetes and obstructive sleep apnea (OSA) was the focus of a small study published by JMIR Formative Research on July 20. It was based on in-depth interviews before and after CPAP treatment with 12 patients and 10 of their partners in Denmark. The interviews found that patients and their partners did not consider OSA to be a serious disorder, believing daytime sleepiness and napping to be normal aspects of aging. After three months of CPAP usage, 11 of 12 patients reported having had technical difficulties with the device, many related to mask fit. The patients who had severe OSA symptoms that they believed affected their daily lives were more likely to overcome the technical challenges and were found to have lost weight, increased activity, and improved their diet on CPAP. Patients with less severe symptoms rated CPAP as more burdensome than their symptoms. “Patients' partners play a large role in promoting the correct use of the CPAP device, which can motivate patients to continue with the treatment,” the authors noted. They acknowledged there are many barriers to CPAP treatment but concluded that when used correctly, “CPAP has the potential to significantly improve OSA, resulting in better sleep quality; improved physical activity; improved diet; and, in the end, better diabetes self-management.”