Obstructive sleep apnea (OSA) is a common cause of daytime sleepiness, and severe OSA is a risk factor for hypertension, cardiovascular events, atrial fibrillation (AF), insulin resistance, cognitive impairment, motor vehicle crashes, adverse pregnancy outcomes, and overall mortality.1-8 The hazard ratio for mortality for patients with severe OSA may be as high as 3.8.5
OSA is diagnosed by the apnea-hypopnea index (AHI), defined as the number of apnea or hypopnea events per hour as determined by polysomnography. An AHI score ≤ 5 is considered normal; > 5 to ≤ 15 is mild; > 15 to < 30 is moderate; and ≥ 30 is severe. Most studies of OSA treatment use reduction of AHI as the measure of treatment effectiveness, and several types of treatment improve AHI.
In family medicine, we generally want to know whether treatment of OSA will improve outcomes of significance to patients. A recent systematic review of evidence for the US Preventive Services Task Force found that it was unclear whether OSA treatment improved most health outcomes, including mortality, cardiovascular events, or motor vehicle crashes.6Several other organizations have published guidelines regarding OSA treatment; these guidelines are reviewed in the TABLE.9-13
This article summarizes the current evidence surrounding the effect of treatment of OSA on outcomes of significance to patients. While multiple treatments have been advocated for patients with OSA, positive airway pressure (PAP) is the most widely used and studied and is recommended as standard treatment by most guidelines.9-13 Most available evidence about patient-oriented outcomes involves treatment with PAP; where there is evidence about the effect of other OSA treatments on a particular outcome, that evidence is also summarized.
Benefits of OSA treatment
Patients with OSA who have excessive daytime sleepiness can gain substantial symptomatic benefit from treatment of their OSA with PAP or oral appliances (OAs), and might benefit from hypoglossal nerve stimulation or other surgical treatment. PAP is probably more effective than OAs in patients who use it ≥ 4 hours/night, but it is more difficult to comply with PAP.14
Evidence that treatment of asymptomatic OSA benefits other medical conditions is often conflicting. Given the low risk of treatment, it is reasonable to consider offering a trial of treatment, preferably with PAP, to asymptomatic patients with moderate-to-severe OSA and certain comorbidities, including obesity, resistant hypertension, high cardiovascular risk, congestive heart failure (CHF), AF, diabetes that is difficult to control, and pregnancy. Such patients should be strongly encouraged to use PAP ≥ 4 hours/night, and should be advised that benefits may not be immediately apparent.
Treatment of OSA improves daytime sleepiness
Daytime sleepiness is typically measured with the Epworth Sleepiness Scale (ESS), a self-administered questionnaire assessing a person’s level of drowsiness and propensity to fall asleep in 8 different daytime situations. Each situation is scored between 0 (would never doze) and 3 (high chance of dozing), with the scores then totaled to provide an overall score between 0 and 24. A score > 10 is considered abnormal.