Comorbidities associated with sleep apnea

People with sleep-disordered breathing (SDB) have an increased risk of developing hypertension, independent of other relevant risk factors.^1-5 This risk is related to SDB severity: the more severe the SDB, the greater the risk of developing hypertension.

During healthy sleep, blood pressure decreases, but SDB patients instead tend to experience:

• elevated blood pressure during sleep;
• prolonged cardiovascular stress, which can lead to increased blood pressure also occurring during the day.

SDB is present in more than 30% of patients with hypertension,⁶ and in around 80% of patients with drug resistant hypertension.⁵ For this group of patients in particular, treatment with positive airway pressure therapy may be especially important.⁷

Up to 50% of heart failure patients experience moderate to severe sleep-disordered breathing (SDB),⁸ in the form of central sleep apnea (CSA), Cheyne-Stokes respiration (CSR), obstructive sleep apnea (OSA)or a combination thereof.⁹

What is Cheyne-Stokes respiration?

Cheyne-Stokes respiration (CSR) occurs when periods of hyperventilation and hypoventilation (in a waxing/waning breathing pattern) alternate with periods of central hypopnoea/apnea. CSR is a common form of SDB in patients with severe left ventricular dysfunction.¹⁰

How does CSR affect heart failure?

It’s thought that SDB and CSR accelerate the progression of heart failure by causing:

• Repetitive hypoxia;
• Increased afterload;
• Increased sympathetic activity;¹¹
• Oscillations in heart rate and blood pressure.

A large MediCare study on newly diagnosed heart failure patients has shown that those with SDB have a worse prognosis compared to those without.¹²Nocturnal CSA/CSR in itself is associated with increased mortality¹³ in congestive heart failure patients.
Learn more about the treatment options for patients with CSR.

The majority of patients who have experienced a stroke and transient ischemic attack also have SDB,¹⁴which is sometimes undiagnosed. As stroke patients with SDB also have worse functional outcomes¹⁵, you should consider screening for SDB¹⁶ when investigating the stroke.

Stroke has the potential to cause SDB, by either affecting:

• central mechanisms resulting in central sleep apnea;
• muscle tone resulting in obstructive sleep apnea.

Can sleep apnea predispose people to strokes?

People with sleep apnea may be predisposed to stroke through a number of symptoms they experience. In particular:

• Repetitive drops in nocturnal blood oxygen levels caused by sleep apnea can result in intermittent hypoxia which has been shown to be associated with systemic inflammation.¹⁷
• Sleep fragmentation from sleep apnea results in hypersympathetic activity.¹⁸

What is the impact of sleep apnea on post-stroke rehabilitation?

Patients with both sleep apnea and stroke usually show poor compliance with post-stroke rehabilitation programs. This is mainly due to the combination of:

• the deficits caused by the stroke;
• the symptoms of SDB (such as excessive daytime sleepiness, fatigue, and impaired cognitive functioning).

How do I recognise and diagnose sleep apnea in stroke survivors?

Recognising sleep apnea in stroke survivors is often challenging because the symptoms associated with sleep apnea are often attributed to strokes. A complete sleep history from family members can help you determine whether sleep apnea was present prior to the stroke or developed after the stroke.

Sleep apnea is common among patients with type 2 diabetes.¹⁹ It is independently associated with insulin resistance, glucose intolerance and metabolic syndrome,^20-22 and when untreated, can lead to poor overall treatment outcomes.

However, despite the number of type 2 diabetes patients with SDB, it largely goes undiagnosed.

Screen your patients for type 2 diabetes and sleep apnea

As patients with sleep apnea and patients with diabetes share similar comorbidities, screening both ways is recommended: check for sleep apnea in diabetes patients, and check for diabetes in patients with sleep apnea.²³

Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease (COPD) are two diseases that often coexist within a patient.

COPD is a condition that describes the progressive deterioration of the respiratory system by pulmonary airway obstruction, emphysema and decreased airflow. COPD also refers to lung disorders such as chronic bronchitis, and in some cases, chronic asthma.

SDB prevalence in COPD patients

According to the American Thoracic Society, patients with Chronic Obstructive Pulmonary Disease (COPD) have a higher prevalence of sleep disorders than the general population, with close to 50% of patients reporting significant disturbance in sleep quality.

Co-existence of both COPD and OSA occurs in 1% of adults.²⁴

COPD risks in SDB patients

COPD and OSA are often coined as overlap syndrome. Both COPD and OSA are independent risk factors for the following:

• Arrhythmia;
• High blood pressure;
• Heart attack;
• Stroke;
• Other cardiovascular disease.

Studies have shown that patients with untreated overlap syndrome have a higher mortality rate¹. We at ResMed strive to impact comorbidity and improve quality of life. We offer a range of treatment options to alleviate the symptoms of COPD.

Although scientists continue to research the risks created by, and associated with, sleep apnea, patients’ sleep-disordered breathing often goes untreated. Learn how to get your patients screened for sleep apnea and how to treat them to diminish the risk of other chronic diseases