Obstructive sleep apnea (OSA) is a common chronic disorder that often requires lifelong care . Cardinal features in adults include:
- Obstructive apneas, hypopneas, or respiratory effort related arousals.
- Daytime symptoms attributable to disrupted sleep, such as sleepiness, fatigue, or poor concentration.
- Signs of disturbed sleep, such as snoring, restlessness, or resuscitative snorts.
OSA is an important disorder because patients are at increased risk for poor neurocognitive performance and medical disorders, due to repeated arousals and/or hypoxemia during sleep over months to years. The severity and duration of OSA necessary for development of these sequelae vary among individuals . In addition, severe untreated OSA has been associated with increased all-cause and cardiovascular mortality.
The epidemiology, risk factors, pathophysiology, and outcome of OSA in adults are reviewed here. The definition, clinical presentation, diagnosis, and treatment are discussed in detail elsewhere. (See "Clinical presentation and diagnosis of obstructive sleep apnea in adults" and "Management of obstructive sleep apnea in adults".)
It is estimated that up to 26 percent of adults are at high risk for OSA [3,4]. The prevalence of OSA in general North American populations is approximately 20 percent if defined as an apnea hypopnea index (AHI) greater than five events per hour (the AHI is the number of apneas and hypopneas per hour of sleep) . In contrast, it is 2 to 9 percent if defined as an AHI greater than five events per hour accompanied by at least one symptom that is known to respond to treatment (eg, daytime sleepiness) [3,5]. Therefore, it is common to be minimally symptomatic and have an AHI in an abnormal range.