New Obstructive Sleep Apnea Screening Recommendation Highlights Gap in Sleep Medicine

Daniel J. Gottlieb, MD, MPH

In an article published today alongside the updated recommendations for obstructive sleep apnea (OSA) screening by the US Preventive Services Task Force (USPSTF), Daniel Gottlieb, MD, MPH, discussed the condition in depth as it relates to the new recommendations.

"For the truly asymptomatic patient, the USPSTF recommendation is sensible, even for most patients with known cardiovascular illness," he wrote. "However, the conflation of 'asymptomatic adults' and 'those with unrecognized OSA symptoms' is troubling, as it may suggest to clinicians that such unrecognized symptoms can be safely ignored."

Gottlieb is the lead investigator and associate physician in the Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital. He also serves as the director of the Sleep Disorders Center at VA Boston Healthcare System, and an associate professor of medicine in the Division of Sleep Medicine at Harvard Medical Medical School.

How Common is Sleep Apnea?

After recounting how the condition emerged with a definitive term in the 1970s, Gottlieb explained that studies have showed apneas and hypopneas during sleep are common in the adult population, despite the condition initially being considered uncommon.

A task force report published by the American Academy of Sleep Medicine (AASM) in 1999 defined “obstructive sleep apnea-hypopnea syndrome” as characterized by heightened frequency of apneas and hypopneas during sleep (the apnea-hypopnea index [AHI]) with the presence of symptoms such as excessive sleepiness, fatigue, or unrefreshing sleep, among others.

"Since that time, however, the requirement for symptoms has been largely dropped from the standard sleep disorders nosology: the diagnosis of adult obstructive sleep apnea (OSA) is made if the AHI is 15 or more events per hour of sleep regardless of associated clinical features, while for those with an AHI between 5 and 15 events per hour, the list of associated symptoms, signs, and comorbid conditions supporting the diagnosis of OSA has been expanded to include insomnia symptoms, habitual snoring, hypertension, diabetes, cardiovascular disease, and mood disorder, among others—a list so broad that an AHI of 5 or greater has become a de facto sufficient criterion for diagnosis of OSA," he wrote.

Based on this definition, obstructive sleep apnea is prevalent among adults, however, the latest estimates from 2010 that reported OSA affects 34% of men and 17% of women between the ages of 30-70 were conservative estimates and would be "considerably higher using the more liberal hypopnea definition currently favored by the AASM", according to Gottlieb.

Clinical Benefit of Screening for Obstructive Sleep Apnea

"The high prevalence of OSA and the availability of effective therapy suggest a potentially large clinical benefit from screening to identify patients with undiagnosed OSA," Gottlieb stated. "However, epidemiology studies have shown that most adults with OSA in the general community do not report excessive sleepiness on standardized instruments, and whether OSA treatment can reduce cardiovascular morbidity and mortality has not been established, raising a reasonable question as to the value of case identification in the general population."

Following a systematic review with the objective of updating the last recommendation statement on screening for sleep apnea in adults, the USPSTF ended up with the same conclusion from 2017:

This recommendation replaces the 2017 USPSTF recommendation on screening for OSA. In 2017, the USPSTF found insufficient evidence to assess the balance of benefits and harms of screening for OSA in asymptomatic adults (I statement). This recommendation statement is consistent with the I statement from 2017.

According to Gottlieb, the task force reached this conclusion due to a scarcity of studies assessing the reliability of OSA screeining measures in the general primary care population, as well as a lack of health outcome comparisons directly investigating screened and unscreened populations.

"The updated systematic review also notes a lack of evidence from clinical trials that treatment of OSA reduces the risk of major adverse cardiovascular events or mortality," he continued. "Although the review excluded the 2 largest randomized trials addressing this question, their inclusion would only reinforce the conclusion that trials have not demonstrated a reduction in cardiovascular risk with OSA treatment."

Ammending the Gaps in OSA Research

The USPSTF report highlighted an unmet need for robust research in order to improve screening strategies for obstructive sleep apnea in the primary care setting. First, it must be determined whether or not routine screening of asymptomatic adults, or those with unrecognized symptoms, by primary care physicians (PCPs) will be beneficial for clinical outcomes.

Lastly, Gottlieb emphasized that a focus on expansive understanding in this field is important, clinicians should not be deterred from identifying and managing unrecognized symptoms of obstructive sleep apnea in presenting patients.

"Ongoing research to identify features of OSA that predict risk of major adverse cardiovascular events and death in asymptomatic people in the general community, such as the degree of associated hypoxemia, the autonomic response to obstructive events, and underlying genetic risk factors, promises to inform the design of clinical trials assessing the potential cardiovascular benefit of OSA treatment in appropriately selected asymptomatic patients," Gottlieb concluded.