Beyond heart health: Consequences of obstructive sleep apnea

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Release date: September 1, 2019
Expiration date: August 31, 2022
Estimated time of completion: 0.75 hour

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Obstructive sleep apnea (OSA) is a serious condition associated with impaired quality of life, depression, drowsy driving and motor vehicle accidents, metabolic disease, and cognitive decline. The mechanisms accounting for OSA and metabolic disease include hypoxia, sleep fragmentation, and systemic inflammation. OSA appears to advance cognitive decline, and the relationship between the 2 conditions may be bidirectional. Treatment of patients with continuous positive air pressure therapy improves many of the impaired outcomes associated with OSA. Greater awareness, screening, and treatment of patients with OSA can reduce the negative consequences associated with OSA.


  • OSA is associated with negative health consequences such as depression, drowsy driving, metabolic disease, and cognitive decline.
  • Several possible mechanisms to explain the health consequences of OSA have been explored.
  • Treatment of patients with OSA may improve outcomes for many of the health consequences associated with OSA.
  • Screening for OSA is important to identify and treat patients to reduce the associated health risks.



Obstructive sleep apnea (OSA) is a serious condition that impacts quality of life and causes drowsy driving and depression. Research also reveals an interrelationship between OSA and metabolic disease and an association between OSA and cognitive impairment.

The diagnostic criteria of OSA are based on the number of apneic or hypopneic episodes per hour of sleep, called the apnea–hypopnea index (AHI) as recorded during sleep testing. Diagnosis of OSA is warranted if the AHI is 15 or more per hour or if the AHI is 5 or more per hour with 1 or more of the following features: sleepiness; nonrestorative sleep; fatigue or insomnia; waking up with breath-holding spells, gasping, or choking; snoring or breathing interruptions; or a coexisting diagnosis of hypertension, mood disorder, cognitive dysfunction, coronary artery disease, stroke, congestive heart failure, atrial fibrillation, or type II diabetes.1

Many patients with an AHI less than 15 may also have OSA, given the number of coexisting medical conditions included in the OSA diagnostic criteria. Heart conditions such as coronary artery disease, atrial fibrillation, and congestive heart failure encompassed in the OSA diagnostic criteria have increased awareness of the link between OSA and heart health. Less well-known, and the subject of this review, are the negative consequences of OSA, particularly poor quality of life, drowsy driving, depression, metabolic disease, and cognitive impairment.


Reduced quality of life is the most fundamental patient-reported outcome of OSA. OSA is associated with excessive daytime sleepiness, inattention, and fatigue, which increase the risk of accidents and medical disability. These quality-of-life impairments are often the main reason patients seek medical care for sleep disorders.2 Improved quality of life is a central goal of OSA treatment and is the best indicator of the effectiveness of treatment.3 Sleep health and its effect on quality of life is an area of focus of Healthy People 2020 (

The American Academy of Sleep Medicine identified quality of life, along with detection of disease and cardiovascular consequences, as an outcome measure for assessing the quality of care for adults with OSA.2 The assessment of quality of life for patients with OSA is a 4-part process: use evidence-based therapy, monitor the therapy, assess symptoms with a validated tool such as Epworth Sleepiness Scale, and assess the incidence of motor vehicle accidents. Information from these 4 processes can inform changes in a patient’s quality of life.

Treatment for OSA has been shown to improve quality of life. A study of 2,027 patients with OSA evaluated therapy adherence relative to mean Functional Outcomes of Sleep Questionnaire and European Quality of Life-5D scores.4 In patients with the most impaired quality of life, those adherent to positive airway pressure (PAP) therapy had improved quality of life as measured by these scores.

With respect to sleepiness, a systematic review of continuous PAP (CPAP) in patients with OSA found a 2.7-point reduction (mean difference; 95% confidence interval 3.45–1.96) in the Epworth Sleepiness Scale in patients using CPAP compared with the control group.5 Treatment of OSA improves patient quality of life and symptoms such as sleepiness.


Drowsy driving by people with OSA can lead to motor vehicle accidents, which result in economic and health burdens.6,7 National Center for Statistics and Analysis data reveal that of 6 million motor vehicle accidents (5-year average, 2005–2009), 1.4% involve drowsy driving and 2.5% of fatal crashes involve drowsy driving.8 Among noncommercial drivers, untreated OSA increases the risk of motor vehicle accidents 3- to 13-fold.9 The odds ratio of traffic accidents in drivers with untreated OSA is 6 times greater than in the general population.7

In a study of men and women in the general population (N = 913), individuals with moderate to severe OSA (AHI > 15) were more likely to have multiple motor vehicle accidents in the course of 5 years (odds ratio = 7.3) compared with those with no sleep-disordered breathing.10 The association between OSA and motor vehicle accidents is independent of sleepiness, and drivers with OSA may not perceive performance impairment.

There are 2 main reasons OSA increases the risk and incidence of motor vehicle accidents. OSA causes changes in attention and vigilance resulting from sleep deprivation and fragmentation. OSA also affects global cognition function, which may be due to intermittent hypoxia attributable to OSA.2

Treatment for OSA is effective in reducing the incidence of motor vehicle accidents. One study found the risk of motor vehicle accidents was eliminated with the use of CPAP treatment in patients with OSA.11 A recent study of nearly 2,000 patients with OSA found a reduction in self-reported near-accidents from 14% before PAP therapy to 5.3% after starting PAP therapy.12


Next Article:

Positive airway pressure: Making an impact on sleep apnea

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