New Guidelines Back Sleep Studies for Daytime Sleepiness

Clinicians should assess the risk factors for and the symptoms of obstructive sleep apnea (OSA) using sleep studies for patients who have unexplained daytime sleepiness, according to new evidence-based guidelines from the American College of Physicians (ACP).

“Obstructive sleep apnea is a serious health condition that is associated with cardiovascular disease, hypertension, cognitive impairment, and type 2 diabetes,” said David Fleming, MD, ACP president. “It is important to diagnose individuals with unexplained daytime sleepiness so that they can get the proper treatment.”

In the new guidelines, the ACP recommends a full-night, attended, in-laboratory polysomnography (PSG) for diagnostic testing in patients in whom OSA is suspected. When PSG is not available, the ACP recommends using a home-based portable monitor.

The guidelines are based on literature in the English language on this topic published from 1966 through May 2013. The evaluated clinical outcomes included all-cause mortality, cardiovascular mortality, nonfatal cardiovascular disease, stroke, hypertension, type 2 diabetes, postsurgical outcomes, and quality of life.

The best-documented risk factor for OSA is obesity, state the guidelines. The clinical symptoms of OSA include unintentional sleep episodes during wakefulness, daytime sleepiness, unrefreshing sleep, fatigue, insomnia, and snoring.

If other causes have been ruled out (eg, thyroid disease, gastroesophageal reflux disease, and other respiratory diseases), further evaluation for OSA may be warranted in patients with daytime sleepiness, which is the clinically relevant OSA symptom most responsive to treatment.

The guidelines also state that evidence is lacking on the effect of continuous positive airway pressure on improving other outcomes, including hypertension, diabetes, coronary heart disease events, and mortality, especially among patients without daytime sleepiness.

Sleepiness questionnaires help clinicians assess the symptom severity of OSA but cannot help assess the apnea–hypopnea index (AHI), a measure of the number of apnea or hypopnea events per hour during sleep, which is a necessary but not sufficient component of OSA. Questionnaires also lack sufficient sensitivity and specificity to replace a sleep study in the diagnosis of OSA.

High-quality evidence showed an association between an AHI score greater than 30 events per hour and greater all-cause mortality. Low-quality evidence showed an association between higher AHI score and diabetes, although obesity probably was a confounding variable in these studies.

Full-night, attended, in-laboratory PSG is considered the reference standard diagnostic test, state the guidelines, and is recommended in patients with suspected OSA. In the absence of PSG, portable monitors may be used as an alternative diagnostic test in these patients.

An AHI score of at least 15 events per hour or at least 5 events per hour with symptoms, such as daytime somnolence and fatigue, is considered a criterion for an OSA diagnosis. Evidence shows that compared with PSG, portable monitors have a wide range of difference in AHI estimates.

“Diagnosing obstructive sleep apnea is high value care,” Dr Fleming said. “Prior to diagnosis, patients with OSA have higher rates of health care use, more frequent and longer hospital stays, and greater health care costs than after diagnosis.”

The guidelines follow on the ACP’s guidance on treatment of OSA issued in September 2013.

The new guidelines were published in the August 5, 2014 issue of the Annals of Internal Medicine.