Seattle — Treating obstructive sleep apnea in patients with type 2 diabetes could improve glycemic control as much as using common antidiabetic drugs, according to the results of an observational study.
Blood glucose levels may be harder to control in cases of untreated OSA, Dr. Renee Simon Aronsohn reported at the annual meeting of the Associated Professional Sleep Societies.
Study results showed that mean glycosylated hemoglobin A1c rose significantly from 6.5% in patients without OSA to 8.7% in those with severe OSA, she said.
The higher HbA1c values also were significantly related to the number of episodes of oxygen desaturation of 3% or more during REM sleep.
In published reports, the prevalence of polysomnography-proven OSA in type 2 diabetes has ranged from 58% to 86%. “Despite this strikingly high prevalence of disease in patients with type 2 diabetes, the impact of OSA on glucose control in this patient population” has remained unknown, said Dr. Aronsohn, an endocrinology fellow at the University of Chicago.
She and her colleagues enrolled 54 patients seen in outpatient clinics during 2000-2008 who had physician-diagnosed type 2 diabetes and were on stable doses of medication. A total of 29 patients were women, and 29 were black.
Participants completed a diabetes and quality of life survey, performed wrist actigraphy monitoring for 5 days at home, underwent overnight laboratory polysomnography, and had a glycosylated HbA1c) measurement.
Patients were classified as having no OSA (apnea-hypopnea index less than 5), mild OSA (5-14), moderate OSA (15-29), or severe OSA (index of 30 or greater).
Overall, 76% of the patients had OSA (mild in 35%, moderate in 26%, and severe in 15%). Compared with their non-OSA counterparts, patients with OSA, on average, were older (60 years vs. 53 years), had a higher body mass index (35 kg/m
In a multivariate analysis that adjusted for potential confounders (age, sex, race, BMI, insulin use, duration of diabetes, and total sleep time), mean HbA1c increased significantly across OSA categories, with values of 6.5%, 7.5%. 7.8%, and 8.7% among patients with no, mild, moderate, and severe OSA, respectively.
“It's important to note that the magnitude of the effect sizes we see here are comparable to—if not exceeding—those seen with widely used pharmacologic agents,” Dr. Aronsohn said.
Dr. Aronsohn noted that a 100% increase in the number of obstructive events during REM sleep, from the median of 35 to 70 events per night, would result in a predicted increase in median HbA1c from 7.2% to 7.7%. “This again is a clinically significant change in hemoglobin A1c value,” she pointed out.
“Our findings suggest that untreated OSA may worsen glucose control and increase the need for more intensive pharmacotherapy,” she said. “Conversely, treatment of OSA may improve glucose control comparable to that of widely used pharmacologic agents.”
Previous studies in patients with type 2 diabetes implicated sleep perturbations in poorer glycemic control, but failed to address OSA as a cause of the sleep problems, she said.
Studies assessing the impact of continuous positive airway pressure treatment on glycemic control in type 2 diabetes have been inconclusive and confounded by compliance issues, she noted. “So, our next step is looking at how treatment affects control.”
Dr. Aronsohn reported that she had no conflicts of interest associated with the study.
'Untreated OSA may worsen glucose control and increase the need for more intensive pharmacotherapy.'
Source DR. ARONSOHN