What Is Obstructive Sleep Apnea Syndrome (OSAS)?
OSAS is characterized by repeated episodes of partial or complete obstruction of the upper airway during sleep, resulting in a reduction (hypopnea) or interruption (apnea) of respiratory flow, often associated with snoring and frequent awakenings, even if these are not always perceived by the patient.
- Habitual and intense snoring
- Apneas reported by a partner or roommate
- Excessive daytime sleepiness
- Headache upon waking
- Frequent awakenings or a sensation of suffocation at night
- Difficulty concentrating and chronic fatigue
The link to obesity
The prevalence of obstructive sleep apnea increases in parallel with the prevalence of obesity: the accumulation of adipose tissue in the neck and upper airways promotes their collapse during sleep. The relationship is bidirectional—obesity contributes to OSAS, and OSAS, through sleep disturbances and related hormonal mechanisms, can in turn contribute to weight gain—and weight loss is associated with a documented reduction in the number and severity of apnea-hypopnea episodes.
Screening: the STOP-BANG questionnaire
It is a simple, validated screening tool consisting of eight yes/no questions used to estimate the risk of obstructive sleep apnea:
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Acronym
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Criterion
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S
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Snoring — habitual and intense snoring
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T
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Tiredness — daytime fatigue/sleepiness
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O
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Observed apnea — apneas observed by others
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P
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Pressure — high blood pressure
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B
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BMI — body mass index greater than 35 kg/m²
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A
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Age — age over 50
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N
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Neck circumference — elevated neck circumference
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G
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Gender — male
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A score of 3 or higher indicates an increased risk of OSAS, while a score of 5 or higher indicates a high risk; the questionnaire showed a sensitivity of 93% in identifying moderate-to-severe OSA and 100% in identifying severe OSA.
The Diagnosis: Polysomnography
Diagnostic confirmation of OSAS requires polysomnography (or a sleep study): a non-invasive test that records a series of physiological parameters during a night’s sleep and is considered the gold standard for diagnosing and assessing the severity of obstructive sleep apnea.
What the test measures
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Parameter
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What it records
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EEG (electroencephalogram)
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Brain activity, to identify the different stages of sleep
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EOG (electrooculogram)
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Eye movements, particularly during the REM phase of sleep
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EMG (electromyogram)
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Muscle tone and activity
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ECG
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Electrical activity of the heart
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Airflow and respiratory effort
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Thoracoabdominal movements and airflow through the nose and mouth
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Oxygen saturation (SpO₂)
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Blood oxygen levels during sleep
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Snoring and body position
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Nocturnal respiratory sounds and sleep position
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In selected cases, blood pressure monitoring and capnography (CO₂ measurement) may be added to the test.
The two methods of administration
In-laboratory polysomnography: the patient spends the night in a dedicated room, with video recording of the test and continuous monitoring by technical staff throughout the night.
Home polysomnography: the entire procedure is performed directly at the patient’s home. Technical staff visit the patient’s home to attach the sensors and set up the equipment, which is then used overnight in the patient’s normal home environment. The following morning, the staff returns to the patient’s home to remove the equipment and retrieve the recorded data. This method does not involve video recording, but it allows for sleep monitoring in a familiar environment, reducing the so-called “first-night effect” and improving the representativeness of the collected data.
How to Prepare for the Test
- On the day of the test, it is recommended that you maintain your usual daily routine
- Avoid alcohol, caffeinated beverages, and sedative medications, unless otherwise directed by your doctor
- Wear comfortable clothing that opens in the front (a shirt or a zip-up sweater) to facilitate sensor placement
- During the night, avoid behaviors that could cause artifacts in the recording, such as using a cell phone or chewing gum
What Happens After the Test
The recorded data are analyzed to calculate the apnea-hypopnea index (AHI) and the oxyhemoglobin desaturation index (ODI), which allow for the classification of the disorder’s severity. The report is then discussed with the specialist, who works with the patient to determine the most appropriate treatment plan.
Severity is classified based on the AHI value:
- Mild: AHI between 5 and 15 events per hour
- Moderate: AHI between 15 and 30 events per hour
- Severe: AHI greater than 30 events per hour
OSAS and Cardiovascular Diseases
Obstructive sleep apnea is associated with hypertension, heart failure, and atrial fibrillation through mechanisms that include mechanical factors, hyperactivation of the sympathetic nervous system, and oxidative stress. Untreated OSA doubles the risk of atrial fibrillation recurrence after electrical cardioversion, while CPAP treatment has been shown to reduce the risk of stroke and, to a lesser extent, blood pressure levels. The 2024 ESC guidelines on atrial fibrillation include sleep apnea among the comorbidities to be actively managed, along with hypertension, heart failure, diabetes, and obesity, as an integral part of the treatment pathway.
OSAS and Respiratory Diseases
OSAS can coexist with other chronic respiratory conditions (coexistence with chronic obstructive pulmonary disease is known in the literature as “overlap syndrome”), with a combined impact on nocturnal oxygenation and sleep quality. In these cases, a specific pulmonology evaluation is recommended to provide a comprehensive assessment of respiratory function and to tailor treatment options.
OSAS and Metabolic Disorders
The link between obstructive sleep apnea and type 2 diabetes is bidirectional: the prevalence of type 2 diabetes is high among patients with OSA, and, conversely, OSA is very common among people with diabetes. OSA is independently associated with alterations in glucose metabolism, increased insulin resistance, and a higher risk of diabetic complications, through shared mechanisms such as intermittent hypoxia, systemic inflammation, and autonomic nervous system dysfunction. The most recent ADA/EASD Consensus on the management of type 2 diabetes has included sleep—in terms of its quantity, quality, and chronotype—among the central elements of disease management.
Why It Is Important to Treat Sleep Disorders
Treating obstructive sleep apnea isn’t just about sleeping better—it means tangibly reducing certain health and personal safety risks, as documented by numerous studies.
Driving Safety
In Italy, it is estimated that about 20–22% of traffic accidents are related to drowsiness while driving, which is often associated with sleep apnea syndrome; Untreated OSA increases the risk of car accidents, with estimates showing an increase of up to 2–7 times compared to the general population, and untreated patients have up to a 7-fold higher risk of falling asleep at the wheel and lapses in attention while driving. CPAP treatment reduces the risk of accidents after just one week of regular therapy.
Regulatory Requirements for a Driver’s License
European Directive 2014/85/EU stipulates that individuals with suspected or confirmed moderate or severe OSAS must undergo a thorough medical evaluation before a driver’s license is issued or renewed. Italy transposed this directive through the Decree-Law of December 22, 2015, and the Decree of the Ministry of Health of February 3, 2016: for patients with moderate or severe OSAS, a driver’s license may be issued or renewed only if symptoms are adequately controlled and there is documented improvement in daytime sleepiness as a result of treatment.
Cardiovascular Risk and Benefits of Treatment
In patients with OSA and high cardiovascular risk, CPAP treatment has been shown to reduce the combined risk of heart attack, stroke, and cardiovascular mortality by 17%.
Cognitive Function and Quality of Life
Regular treatment with CPAP is associated, as early as approximately three months into therapy, with a significant improvement in attention, short- and long-term memory, and overall cognitive function, as well as in perceived sleep quality and daytime sleepiness.
The importance of treatment adherence
The benefits of therapy depend directly on how consistently it is followed: CPAP use of 4 hours or more per night, on at least 70% of nights, is considered the minimum threshold for achieving significant vascular protection.
Severe, untreated daytime sleepiness increases the risk of accidents while driving and at work; if OSAS is suspected, it is important to report it to your doctor, including when applying for or renewing a driver’s license, as required by current regulations.
Treatment should never be discontinued on your own without first consulting a specialist.
Treatment Options
Weight Loss and Lifestyle
Weight loss, achieved through a structured nutritional program, is a first-line intervention in cases of obesity, with documented reduction in the severity of OSAS; it is managed in collaboration with AlleviO₃’s Nutritional Medicine department.
CPAP — Continuous Positive Airway Pressure
This is the gold standard treatment for moderate-to-severe OSAS: a device delivers a continuous stream of positive-pressure air through a mask, keeping the upper airways open during sleep.
Oral devices
Mandibular advancement devices are an option in mild-to-moderate cases or for patients who cannot tolerate CPAP, and are evaluated in collaboration with dental specialists.
Pharmacological therapy: the role of tirzepatide
The Phase 3 SURMOUNT-OSA study (published in the New England Journal of Medicine, June 2024) demonstrated that tirzepatide, in adults with obesity and moderate-to-severe OSA, reduces the apnea-hypopnea index and improves several cardiometabolic markers, including systolic blood pressure, compared to placebo. In the United States, the FDA approved tirzepatide in December 2024 as the first drug specifically indicated for moderate-to-severe OSA associated with obesity; in Europe, however, the EMA determined that the benefit for OSA is already covered by tirzepatide’s existing authorization for weight management, without requiring a separate indication.
Surgery
In cases refractory to conservative treatment, otolaryngological surgical options targeting the upper airway may be considered; or, in patients with severe obesity, bariatric surgery may be considered in collaboration with Outpatient General Surgery and Nutritional Medicine.
A Multidisciplinary Approach at AlleviO₃
The management of obesity-related sleep disorders requires the involvement of multiple specialties within the center:
- Nutritional Medicine, for weight management
- Outpatient Cardiology, for the assessment and monitoring of cardiovascular risk (hypertension, atrial fibrillation)
- Internal Medicine, for the management of metabolic comorbidities, particularly type 2 diabetes
- Outpatient General Surgery, for cases requiring evaluation for bariatric surgery
When to See a Specialist
- Habitual and intense snoring, also reported by a partner
- Sleep apnea observed by a roommate
- Excessive daytime sleepiness, even during sedentary activities
- Headache upon waking or non-restorative sleep
- Obesity associated with poorly controlled high blood pressure or type 2 diabetes
An integrated approach to sleep, weight, and cardiometabolic health
AlleviO₃ addresses obesity-related sleep-disordered breathing through a program that combines diagnosis via polysomnography, weight management, and monitoring of cardiovascular and metabolic comorbidities.
Scientific references
Verification performed during this session: the STOP-BANG questionnaire and its sensitivity/specificity data were confirmed; the parameters recorded during polysomnography and the two main testing modalities were confirmed; the OSA severity classification based on AHI was confirmed; the link between untreated OSA and recurrence of atrial fibrillation was confirmed, as was the inclusion of sleep apnea among the comorbidities addressed in the 2024 ESC guidelines on atrial fibrillation; the bidirectional link between OSA and type 2 diabetes and the role of sleep in the ADA/EASD Consensus were confirmed; the results of the SURMOUNT-OSA study and the FDA’s December 2024 approval of tirzepatide were confirmed, with the EMA taking a different stance in Europe; Confirmed data on the risk of traffic accidents associated with untreated OSA, the 17% reduction in cardiovascular risk with CPAP, cognitive improvement after approximately three months of therapy, and Italian and European regulations on OSAS and driver’s licenses (Directive 2014/85/EU, Decree-Law 22/12/2015, Ministerial Decree of February 3, 2016).
