By Sree Roy
Like many sleep medicine stakeholders, I felt the stirrings of something momentous when first Samsung, soon followed by Apple, received the OK from the Food and Drug Administration (FDA) to market their over-the-counter devices that assess risk for sleep apnea in the United States. Hordes of the 23 million-plus people with undiagnosed moderate to severe obstructive sleep apnea (OSA) would effortlessly be alerted to their potential of harboring the sleep disorder, I thought.
I have since tempered my expectations of what the risk detection features will mean for consumers who are unaware or in denial of OSA symptoms. That’s mostly because I learned neither of these smartwatch/health app combinations turns on the alert mechanism automatically.
The Samsung feature “is intended for on-demand use,” says Jeffrey Kim, a senior product manager at Samsung Electronics America. It monitors, on request, two nights of oxygen sensor data at a time. The accelerometer sensor-based Apple Watch feature runs opportunistically in the background, but only after the user sets up sleep tracking and passes checks for the FDA’s intended user criteria.
But I have high expectations for another group impacted by these consumer smartwatch sleep apnea risk alerts: sleep medicine-referring physicians.
The biggest impact will be on the doctors—from primary care physicians to cardiologists to gynecologists and more—who had been dismissing their patients’ sleep complaints, prescribing hypnotics without a full sleep evaluation, or referring patients to specialties like psychiatry for “depression”-related sleepiness.
Simultaneously, the alerts—and the evidence, like the exportable PDF Apple provides to users flagged for sleep apnea risk—will lend people the confidence to approach physicians about their sleep. And since the likelihood of a physician making a referral for OSA evaluation increased by a factor of nearly 10 when patients specifically inquired about OSA, at least according to one study’s findings,1 these alerts are poised to make a huge difference in OSA diagnosis.
OSA Screening: Benefits Versus Harms
The smartwatch features appear to work as well as (and possibly even better than) existing screeners like the Epworth Sleepiness Scale. Samsung’s sensitivity is 82.7% and modified specificity is 91.1%; Apple’s sensitivity is 66.3% and specificity is 98.5%. Both were designed with low-ish sensitivities to minimize false positives. Both were tested on large numbers of people across the spectrum of sleep apnea severities, including those with normal breathing. Caveat: This is based on their FDA submissions, not on peer-reviewed studies.
But, curiously, with these FDA nods, the country has effectively opted in to a grand screening experiment without knowing if flagging people at scale will have benefits that outweigh harms.
The US Preventive Services Task Force has researched the potential of OSA screening on asymptomatic adults numerous times, most recently in 2022, and come up empty-handed.2 According to the task force, zero studies have been published on the harms of screening the general population for OSA or on the financial costs of the OSA diagnostic pathway, and only a few have detailed the potential physical harms of OSA therapy.
For its part, Samsung, in its De Novo documents, details risks ranging from false positives and false negatives to misinterpretation of device output to electrical shocks. It also lists the methods—like specific testing and labeling—in place to mitigate the risks.
I don’t fault technology companies for pressing forward with features that make their smartwatches more appealing, but I do worry about unintended consequences.
“In the patients who get a positive screen, I think that that is a beneficial thing for them,” says Steven Holfinger, MD, MS, vice chair for the American Academy of Sleep Medicine (AASM)’s emerging technologies committee. “I also think it’s yet to be seen if the net effect is truly positive—because there are a lot of things that could potentially go wrong. For example, we don’t know how many patients who get a negative screen are not going to seek care when otherwise they should.”
Also, it’s not exactly the general population that wears smartwatches. It’s skewed toward Hispanic, Gen-Z, college-educated women with full-time employment.3
“If you’re viewing a strategy of population screening through the lens of ‘we’re going to allow this to kind of naturally happen this way where patients screen themselves—but only the patients who can afford it can do so,’ then that’s not really the optimal strategy to screen a population, I would imagine,” Holfinger says.
Increased Burden on Sleep Physicians?
Sleep specialists raise concerns about whether easier access to sleep apnea risk detection will overburden private practices and sleep labs, increasing waitlists and potentially flooding facilities with people who have subclinical sleep apnea.
On this subject, I agree with sleep specialist Sairam Parthasarathy, MD, who responds, “Then what do we do: let them remain undiagnosed? That’s not a good scenario. Maybe this is what pushes forward a change in health policy…It is incumbent upon us to find solutions that are more efficient.”
Parthasarathy, the Murray and Clara Walker Chair, chief of the division of Pulmonary Critical Care and Sleep Medicine, and director of the UArizona Health Sciences Center for Sleep and Circadian Sciences at the University of Arizona, says payor requirements like face-to-face visits, perfect documentation, and other red tape stymie sleep care. Perhaps greater public and physician awareness of sleep apnea will propel much-needed changes.
Without peer-reviewed evidence, the risks of people with subclinical sleep apnea being notified by their watches are harder to weigh. For that one patient, the sleep clinic visit may have a net benefit, perhaps sparking them to address modifiable risk factors (like weight or smoking status). But they may have harmed another patient who needed that appointment at the backlogged sleep physician’s practice.
That said, neither of these smartwatch-based features is intended to flag mild sleep apnea. Many of the false negatives (compared to polysomnography) in Samsung’s study “are on the border of mild and moderate sleep apnea, making them difficult to classify,” notes the FDA documentation. “These borderline users can also choose to test again in a few months, where the device is likely to produce a positive classification if their sleep apnea has worsened.”
Who Will You Alert?
Since the devices are on the market now, sleep specialists should figure out how to use them for people’s benefit. “Rather than focus on the flaws of these tests, let’s see how to capture the strengths of the tests and harness them to improve the lives of the people who we can get to,” Parthasarathy says. “Let’s take something good and make the most of it.”
After the Apple Watch sleep apnea feature was FDA cleared, I urged a relative to start wearing his smartwatch at night. For years, he has ignored my pleas to see a sleep physician for an OSA evaluation, but I suspect (and hope) he assigns his watch more credibility.
The AASM encourages primary care physicians to screen people at high-risk for OSA, which “may include, but are not limited to, patients with obesity, heart failure, atrial fibrillation or other arrhythmias, coronary artery disease, hypertension, stroke, pulmonary hypertension, prediabetes or diabetes, craniofacial anomalies, sleep complaints, sleepiness, pregnancy, patients undergoing evaluation for bariatric or other applicable surgical procedures.”4 Perhaps those should also become the medical specialties that sleep physicians alert to the benefits of the Apple and Samsung sleep apnea detection features. (Though, unfortunately, Samsung’s feature excludes some of these from use, including people with atrial fibrillation.)
That’s the most timely question I have for all of you: Which physician colleagues in other specialties will you encourage (or discourage) to be part of this grand OSA risk identification experiment?
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References
1. Williams NJ, Nunes JV, Zizi F, et al. Factors associated with referrals for obstructive sleep apnea evaluation among community physicians. J Clin Sleep Med. 2015 Jan 15;11(1):23-6.
2. Feltner C, Wallace IF, Aymes S, et al. Screening for obstructive sleep apnea in adults: Updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2022;328(19):1951-71.
3. Shandhi MMH, Singh K, Janson N, et al. Assessment of ownership of smart devices and the acceptability of digital health data sharing. NPJ Digit Med. 2024 Feb 22;7(1):44.
4. Lloyd RM, Crawford T, Donald R, et al. Quality measure for screening for adult obstructive sleep apnea by primary care providers: 2024 update after measure maintenance. J Clin Sleep Med. 2024 Nov 1;20(11):1819-22.
