Megan Brooks

June 07, 2013

BALTIMORE, Maryland — All patients with type 2 diabetes or hypertension should be evaluated for sleep apnea by a board-certified sleep medicine physician, the American Academy of Sleep Medicine (AASM) advised this week in a position statement.

"Type 2 diabetics and people with hypertension are much more likely to have obstructive sleep apnea (OSA) than other people, and as a result should immediately discuss their risk for sleep apnea with a sleep specialist," AASM President M. Safwan Badr, MD, said in statement.

"Diagnosis and treatment of sleep apnea from a board-certified sleep medicine physician will promote improvement in these conditions — including improved insulin sensitivity, blood pressure and cholesterol," Dr. Badr said.

The AASM's position statement, announced here this week at SLEEP 2013: Associated Professional Sleep Societies 27th Annual Meeting, is based on new research presented at the conference.

Advice Fueled by New Research

Esra Tasali, MD, from University of Chicago, Illinois, reported data from a study showing that good adherence to continuous positive airway pressure (CPAP) improves glycemic control in patients with OSA and type 2 diabetes.

The study included 13 patients with a mean age of 54 years, mean body mass index of 39.2 kg/m2, hemoglobin A1c of 7%, and severe OSA (apnea hypopnea index [AHI] ≥ 30). Nine patients were randomly assigned to optimal CPAP and 4 to sham-CPAP treatment.

Both groups spent each night in the sleep laboratory. Optimum CPAP adherence was achieved by continuous supervision under polysomnography. Body weight and the dosage and timing of antidiabetic medications did not change over the study period, and none of the patients were taking insulin.

Dr. Tasali reported that with optimal CPAP, average 24-hour glucose levels were reduced by 11.3 mg/dL (142.8 vs 131.5 mg/dL; P = .038), and the postbreakfast glucose response was reduced by 19.9 mg/dL (164.9 vs 145.0 mg/dL; P = .028).

Optimal CPAP also had positive effects on the dawn phenomenon — an early-morning increase in plasma glucose levels that occurs in type 2 diabetes despite continuous fasting, which they quantified by subtracting nocturnal nadir glucose from prebreakfast glucose levels. With optimal CPAP, the dawn phenomenon was reduced by 45% (11.6 vs 20.7 mg/dL; P = .038).

"The magnitude of these beneficial effects of CPAP translates to a reduction in hemoglobin A1C by 0.5%, similar to that achieved by commonly prescribed oral pharmacologic agents," the research team notes in a meeting abstract.

Sleep Apnea May Drive Uncontrolled BP

Harneet Walia, MD, from the Cleveland Clinic in Ohio, reported data showing that severe OSA contributes to poorly controlled hypertension in patients with cardiovascular risk factors or cardiovascular disease despite aggressive use of blood pressure medication.

"Sleep apnea is considered to be one of the secondary causes of resistant hypertension, but it is not routinely checked for in this patient population," Dr. Walia noted in an interview with Medscape Medical News.

She and her colleagues analyzed baseline data for 318 patients in the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study, a multicenter randomized controlled trial investigating the effect of OSA treatment on cardiovascular risk in patients with moderate to severe OSA and managed primarily by cardiovascular specialists.

Seventy-three of these patients were taking 3 or more antihypertensive medications, including 1 diuretic. In this group, the researchers found that resistant blood pressure (≥130/80 mmHg) was more prevalent in severe OSA than in moderate OSA (58.3% vs 28.6%; P = .01).

The odds ratio, adjusted for age and body mass index for resistant blood pressure, was 3.29 (95% confidence interval [CI], 1.01-10.74) in patients with severe OSA who were receiving or more antihypertensive medications, including a diuretic.

"These findings are important from a clinical perspective because poor blood pressure control in patients taking multiple antihypertensive medications increases cardiovascular risk, and severe sleep apnea may be driving uncontrolled blood pressure in this group," Dr. Walia said.

The study by Dr. Tasali was supported by the National Institutes of Health and Philips/Respironics. The study by Dr. Walia was supported by the National Institutes of Health. The authors have disclosed no relevant financial relationships.

SLEEP 2013: Associated Professional Sleep Societies 27th Annual Meeting. Abstract 0344. Presented June 4, 2013. Abstract 0324. Presented June 5, 2013.

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