Sleep Apnea Diagnosis: Awareness and Tools

Obstructive sleep apnea (OSA) remains a significantly underdiagnosed condition, despite its high prevalence. Primary care physicians play a pivotal role in identifying patients afflicted by this condition. To effectively diagnose OSA in primary care, increasing awareness and enhancing communication are imperative. Fortunately, several straightforward diagnostic tools are readily available, and even more sophisticated ones, driven by artificial intelligence, are on the horizon.

Recognize the Problem

At the European Respiratory Society (ERS) International Congress 2023, held in Milan, Italy, Cláudia Sofia De Almeida Vicente Ferreira, a family physician from Coimbra, Portugal, and coordinator of the Respiratory Diseases Interest Group (GRESP) of the Portuguese Association of General and Family Medicine (APMGF), highlighted the challenges of diagnosing OSA.

"Sleep apnea is underdiagnosed because the most common symptoms, like excessive daytime sleepiness or snoring, are undervalued by patients. People do not come to the doctor and complain about it. Sometimes you catch it in the middle of other things," she told Medscape.

Moreover, physicians' busy schedules and limited appointment times often lead to a focus on the symptoms reported by patients, and insufficient attention is paid to the quality of sleep. This may be compounded by a tendency among medical professionals to underestimate the risks associated with OSA, as it is not directly linked to mortality, despite its clear connection to cardiovascular risks.

Identifying and recognizing risk factors can facilitate OSA suspicion during patient evaluations. These factors encompass both structural (eg, craniofacial and upper airway anomalies) and nonstructural elements (eg, smoking, alcohol use, or sedative consumption). While men are at higher risk, postmenopausal women who are not receiving hormone replacement therapy face similar risks. Certain medical conditions, such as hypothyroidism, acromegaly, amyloidosis, Cushing syndrome, and Down syndrome, have also been associated with OSA. A comprehensive physical examination can provide additional clues. Factors might include obesity, neck circumference, Mallampati score, and nasal and pharyngeal problems.

Inquire Actively

Once the possibility of OSA is considered, the next step is to ask patients about their symptoms. Questionnaires are simple yet valuable tools for this purpose. The STOP questionnaire comprises four key questions:

Do you SNORE loudly (louder than talking or loud enough to be heard through closed doors)?
Do you often feel TIRED, fatigued, or sleepy during daytime?
Has anyone OBSERVED you stop breathing during your sleep?
Do you have or are you being treated for high blood PRESSURE?

The STOP-BANG questionnaire adds four clinical attributes:

Obesity (BMI > 35 kg/m²)
Age (>50 years)
Neck size (>40 cm, or 16 inches)
Sex

Patients are classified as being at low, intermediate, or high risk for OSA.

The Epworth Sleepiness Scale, which is self-administered, is also useful: patients rate the likelihood of falling asleep in various daytime contexts. These questionnaires can be seamlessly integrated into routine patient appointments.

Comorbidities and Occupation

Primary care physicians should carefully assess comorbidities, especially those linked to cardiovascular risk. Patients with resistant hypertension, pulmonary hypertension, and recurrent atrial fibrillation following cardioversion/ablation should be prioritized for diagnostic testing for OSA. Patients with other conditions, such as coronary artery disease or cerebrovascular disease, should also be referred to a sleep center if OSA is suspected on the basis of comprehensive sleep assessment. OSA has also been associated with type 2 diabetes, metabolic syndrome, and asthma.

Gaining access to sleep study services and subsequent therapy, such as continuous positive airway pressure (CPAP), can be challenging. Primary care physicians should prioritize patients on the basis of their risk levels. Occupation plays a significant role in this prioritization, as sleep fragmentation and daytime sleepiness can lead to workplace and vehicular accidents.

"You should include the occupation in the patient's profile. What is he doing? Is he sitting at a desk, or is he working at height, driving, or operating machines? These workers are high-risk patients," continued De Almeida Vicente Ferreira.

"I think that the family physician has a key role in the follow-up. Nobody else will look for CPAP compliance and will verify if CPAP is working or not. If the patient is not using it or if it is not effective, still there is someone paying for the machine (the national healthcare system or an insurance company). More importantly, if CPAP is not working, we are not improving our patient's life in terms of reducing cardiovascular risk and ameliorating the quality of life."

Is Home Testing a Viable Option?

Diagnosing OSA typically relies on overnight polysomnography in specialized sleep clinics, which is often associated with long waiting lists. Researchers are actively working on innovative sensors and digital solutions for home-based sleep testing, but according to De Almeida Vicente Ferreira, they are not yet ready for prime time: "Home-based studies with fewer evaluation parameters (such as pulse and oxygen levels) are not so secure or sensitive to establish a correct and complete diagnosis. Actually, the architecture of sleep is very complex. The test must be performed and read by a specialized team."

Still, according to Renaud Tamisier, professor of clinical physiology at the Université Grenoble Alpes (La Tronche, France), simplified sleep testing could be very useful. "There are many patients that still are not diagnosed despite having severe sleep apnea, with symptoms and comorbidities. These patients usually are not aware of their disease but complain about changes in their quality of life with excessive tiredness and sleepiness. Also, they are not connected to the healthcare system, for different reasons, including no time for consulting a sleep physician and performing a polysomnography, health cost, negligence. Therefore, providing through primary care a simple diagnostic approach deserves efforts and research," he told Medscape.

New technologies could enable diagnostic sleep tests to be conducted at home, with the added benefit of multiple-night recordings to overcome the challenges of night-to-night variability in the apnea-hypopnea index. These novel testing methods should be cost-effective, easy to install, and user friendly. Tamisier continued: "The issue about sleep diagnosis is that up to now, there was no such devices available. Many physicians use type III sleep recording that are dedicated to highly trained sleep scorers, but they use automatic analysis which in many cases is unsuccessful. For a trained sleep physician, it is easy to see that the result is inaccurate. New devices are being built for automatic analysis using artificial intelligence algorithms. Because by design they are automatic, the rate of success is very high, and if used with the right purpose, they could be highly effective and quick."

In conclusion, the diagnosis of sleep apnea in primary care is becoming more feasible with advancements in diagnostic tools and technology. However, it is crucial for primary care physicians to exercise caution in cases in which the clinical presentation is not straightforward or when OSA is associated with comorbidities. Care management and clear boundaries are vital to ensure effective treatment and improve patient outcomes.

Ferreira and Tamisier have disclosed no relevant financial relationships.

European Respiratory Society (ERS) 2023 International Congress.

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