How sleep specialists navigate the complexity of when and how to treat mild sleep apnea, including why asymptomatic patients still need attention.

By Alyx Arnett

While sleep specialists generally agree that moderate to severe cases of sleep apnea should be treated, the decision whether to treat mild sleep apnea is often more complex. The risks associated with mild sleep apnea are not as well-defined, and not everyone who has an apnea-hypopnea index (AHI) of between five and 15 is symptomatic, adding further ambiguity. 

The American Academy of Sleep Medicine (AASM)’s clinical practice guideline recommends CPAP for moderate to severe sleep apnea, due to evidence supporting its association with consequences such as an increased risk of cardiovascular disease. However, the AASM only recommends CPAP as an option for mild sleep apnea, citing insufficient, inconclusive, or conflicting evidence or expert opinion.¹ 

Some sleep specialists believe AHI isn’t the best indicator for determining when to treat patients with mild disease, as it doesn’t directly correlate to symptoms. Symptom severity can vary widely among patients in the mild range.  

Many experts agree there’s no one-size-fits-all solution when deciding when to treat mild sleep apnea. “It’s still very much a combination of trial and error,” says David Rapoport, MD, director of research in integrative sleep medicine at Icahn School of Medicine at Mount Sinai.

Challenging the Definition of Mild Sleep Apnea

According to Rapoport, some sleep specialists argue that scientific evidence is strong enough to advocate for treating all individuals with an elevated AHI. But, he says, too many people meet the clinical definition.

According to the American Heart Association, over one-third of middle-aged men and nearly one-fifth of middle-aged women meet the definition of mild or more severe sleep apnea.² Rapoport says research he has been involved in shows 70% of people over age 65 meet the definition.

“Whenever you look at any dataset of more than a few people or an epidemiologist study that includes a group, a vast majority of patients meet the definition of sleep apnea. And that is kind of troublesome,” Rapoport says. “The concept of a disease is something not everybody has, so if everybody has something, it’s very hard to call it a disease … And so one of the problems that we have is just exactly what does ‘mild sleep apnea’ mean?” 

Disease can be defined by the presence of a physiologic abnormality. In mild sleep apnea, if someone doesn’t have symptoms and can’t prove consequences, “then it’s very hard to say for sure it’s a disease,” Rapoport says.  

So Rapoport and other sleep specialists often look at the subgroup of people who meet the clinical definition of sleep apnea but also exhibit symptoms, like excessive daytime sleepiness, as the group to focus on treating.

Treating Symptomatic Patients

Ann Romaker, MD, clinical professor of medicine at the University of Cincinnati and director of the university’s sleep medicine program, categorizes mild sleep apnea patients into two groups: those who exhibit excessive daytime sleepiness and those who do not.

A recent study sought to determine how prevalent excessive daytime sleepiness is among patients with mild AHI elevations. Researchers identified 155 patients with mild sleep apnea and found objective sleepiness in 36%.³

The study determined that objectively sleepy patients with mild sleep apnea had greater total sleep time, increased sleep efficiency, and decreased wake after sleep onset time compared to mild sleep apnea patients without sleepiness, suggesting the subgroup of sleepy patients may benefit from treatment. 

Romaker finds her sleepy patients often do well with treatment. “You have mild OSA patients who are very sleepy, and you change their life, just like you do with the moderate ones,” she says. 

Rapoport also has observed marked improvements in mild sleep apnea patients with sleepiness when treated and has confirmed this with multiple sleep latency tests in some cases. Notably, a study he co-authored found that CPAP treatment led to better functional outcomes for patients with mild and moderate obstructive sleep apnea who were experiencing sleepiness.⁴ These findings are supported by the American Thoracic Society, which concluded in a research statement that treatment of mild sleep apnea may benefit individuals with subjective sleepiness.⁵

Other symptoms patients may exhibit include chronic non-restorative sleep, sleep maintenance insomnia, and morning headaches. Joseph Krainin, MD, FAASM, medical advisor for sleepapnea.org, says treatment can also alleviate these symptoms and “significantly” improve quality of life.

Factoring in a patient’s willingness to accept and adhere to treatment also plays a role in some clinicians’ decisions to treat. “Sometimes it has to do with how much work it is to coax people with mild disease to actually be compliant with therapy,” says Romaker. “And there are some people who may not need it. Let’s find out who we can really help, and let’s direct our efforts to where they will make the most difference.” 

Confirm ‘Asymptomatic’ Patients Truly Lack Symptoms

In some cases, people with mild sleep apnea who claim to be asymptomatic have simply adapted to their symptoms. Krainin likens these patients to the frog in the infamous boiling frog fable. That is, the heat is turned up so slowly the frog doesn’t notice the water is boiling. “Patients can experience such gradual deterioration in their sleep quality and daytime function that they may be unaware there is a problem,” he says. 

Before deciding not to treat asymptomatic patients, sleep specialists should dig deeper.

For example, Krainin will ask patients whether they have experienced a change in the amount of sleep they need to feel refreshed. If they used to only need seven hours to feel refreshed but now need nine, that could indicate an underlying issue. It’s also important to clarify the meaning of “sleepiness” with patients, he says. Some may not understand that it includes the tendency to fall asleep unintentionally in passive situations. 

“I’ve had many patients tell me that they have no symptoms during the day. But when I ask them how long they can read, they tell me, ‘Oh, I can’t read. I fall asleep immediately,’” Krainin says. 

Asking patients how long they sleep, including naps, also is key, says Romaker. She had a patient who didn’t report sleepiness, but when she started asking more questions, she found out the patient was sleeping 14 hours a day, 10 at night and several more during the day while watching television or reading. “Once he was treated, he was just astonished at how much better he felt,” she says. 

Romaker generally looks closer at patients who are sleeping longer than eight hours a night but aren’t naturally long sleepers. 

Consider Sleep Apnea Comorbidities

Some sleep specialists also recommend looking at the presence and severity of comorbidities, as untreated sleep apnea can potentially aggravate underlying conditions, while treatment, in certain cases, may yield better long-term health outcomes. 

Despite a lack of long-term studies focused on the effects of treatment on comorbidities in mild sleep apnea patients specifically, some sleep experts have observed favorable outcomes in patients. Atul Malhotra, MD, research chief of pulmonary, critical care, and sleep medicine at the University of California, San Diego, has seen improvements in patients’ blood pressure. “We have some prior individual patient meta-analyses and other studies where we look at the CPAP benefit in terms of blood pressure, and you certainly see it in patients with mild disease,” says Malhotra. 

Romaker, who notes further studies on the topic are critical, has seen benefits in patients with atrial fibrillation after CPAP treatment. “It seems that it makes a difference,” she says. “My clinical impression is that it’s not 100% but that it’s better.”

Comorbidities in mild sleep apnea patients also have been linked to cognitive decline, perhaps surprisingly, in middle-aged men. A new study published in Frontiers in Sleep found that cardiovascular and metabolic comorbidities in male patients aged 35 to 70 with sleep apnea “likely worsen and perpetuate any cognitive deficits caused directly by sleep apnea itself.”⁶ 

Age may be worth taking into account too, says Romaker. According to her, studies have demonstrated that the younger an individual with sleep apnea is, the more cardiovascular risk they have, whereas those over age 65 tend to be more resilient to the effects of sleep apnea. “Maybe we should be treating mild sleep apnea patients at least until they are over 65,” she says. 

Tailoring Sleep Apnea Treatment to Mild Cases

CPAP isn’t the only treatment option for sleep apnea, and some sleep specialists find there’s even more range to trial different therapies for patients in the mild category. 

“With the moderate patients, I come in really trying to convince them that they really want the CPAP machine,” says Romaker. “And with the mild ones, I tell them there are a variety of choices, and what matters is that we find the one that works for them.” Treatment options include positional therapy, oral appliances, and nasal devices. 

Malhotra has found that oral appliances offer “reasonably good outcomes” in mild sleep apnea and that surgery can be helpful as well. He also sees promise in daytime sleep apnea treatment exciteOSA, which he has studied. Malhotra and co-investigators found exciteOSA improved sleep apnea severity, snoring, and subjective sleep metrics, “potentially crucial in mild OSA.”⁷ He adds that diet, exercise, and weight loss shouldn’t be overlooked as “quite effective” treatment options. 

According to Rapoport, the field is evolving and becoming more open to different therapies. In the past, sleep specialists typically would prescribe CPAP to almost everybody and only use oral appliances when the patent rejected CPAP or when it failed to work, he says. That’s not so much the case today. “So there’s now a growing feeling that you can probably triage things a little bit by the severity,” Rapoport says, noting that oral appliances are an acceptable first choice for mild sleep apnea patients. 

Krainin still recommends PAP as the preferred first-line therapy for mild sleep apnea, but he says he brings up the option of alternative therapies, such as oral appliances and nasal EPAP.

For Malhotra, his level of aggressiveness in intervention is guided by symptoms, AHI, comorbidities, and a patient’s willingness to accept treatment. 

Romaker agrees that treatment for this population depends on many factors. “We’re realizing that everybody’s not the same. Everybody’s genetics are not the same. Their anatomy is not the same, and so I don’t believe we’re going to come up with a one-size-fits-all and say that AHI is the only factor that will determine whether they should be treated or not,” she says. 

References

1. Epstein LJ, Kristo D, Strollo PJ, et al. Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults. J Clin Sleep Med. 2009 June 15;5(3)263-76. 
2. Yeghiazarians Y, Jneid H, Tietjens JR, et al. Obstructive sleep apnea and cardiovascular disease: A scientific statement from the American Heart Association. Circ. 2021 Jun 20;144(3):56-67. 
3. Landzberg D, Bagai K. Prevalence of objective excessive daytime sleepiness in a cohort of patients with mild obstructive sleep apnea. Sleep Breath. 2022 Sept;26(3):1471-7. 
4. Weaver TE, Mancini C, Maislin G, et al. Continuous positive airway pressure treatment of sleepy patients with milder obstructive sleep apnea: results of the CPAP Apnea Trial North American Program (CATNAP) randomized clinical trial. Am J Respir Crit Care Med. 2012 Oct;186(7):677-83. 
5. Chowdhuri S, Quan SF, Almeida F, et at. An official American Thoracic Society research statement: Impact of mild obstructive sleep apnea in adults. Am J Respir Crit Care Med. 2016 May 1;193(9):e37-54. 
6. Gnoni V, Mesquita M, O’Regan D, et al. Distinct cognitive changes in male patients with obstructive sleep apnoea without co-morbidities. Front Sleep. 2023 April 6;2. 
7. Nokes B, Baptista PM, de Apodaca PMR, et al. Transoral awake state neuromuscular electrical stimulation therapy for mild obstructive sleep apnea. Sleep Breath. 2022 May 27;10.1007/s11325-022-02644-9.

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