1. Patients experiencing unexplained daytime sleepiness should be tested for obstructive sleep apnea.
2. Polysomnography is the preferred diagnostic test for obstructive sleep apnea.
Evidence Rating Level: 2 (Good)
Study Rundown: Obstructive sleep apnea (OSA) is a disorder that is highly prevalent in the United States, especially in the elderly and obese populations. OSA can significantly disrupt sleep and result in hypersomnolence, impaired concentration, and decreased quality of life. Notably, symptoms such as daytime sleepiness are not observed in all patients with OSA, which only increases the need for an accurate diagnostic test.
The ACP conducted a systematic review of the literature to determine the most effective test for diagnosing OSA. Their metric for efficacy was the apnea/hypopnea index (AHI), which measures the number of times apnea or hypopnea occurs per hour during sleep. Based on the literature, the minimum AHI threshold for a diagnosis of OSA was between 5 and 20 events per hour. The review suggests that polysomnography (PSG) is the preferred diagnostic test for OSA, but portable sleep monitors are still a viable option for patients who cannot access a facility equipped for PSG testing. The ACP also encourages patients with unexplained hypersomnolence to undergo a sleep study, regardless of the testing method used. The quality of the evidence used in this review was moderate at best, which weakens the ACP’s recommendations.
Click to read the study in Annals of Internal Medicine
Relevant Reading: Does this patient have obstructive sleep apnea? The rational clinical examination systematic review
In-Depth [systematic review]: The literature search conducted by the authors included peer-reviewed, English-language articles published between 1966 and May 2013. Searches were conducted using MEDLINE, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews. The studies all had minimum AHI diagnostic thresholds for OSA ranging from 5 to 20 events per hour. Although PSG remains the gold standard for clinical diagnosis of OSA, portable monitors and questionnaires are also used by many clinicians. This review found moderate evidence suggesting that type II and type III monitors can accurately diagnose OSA. Type IV monitors are also an option, but there is some indirect evidence that suggests type III monitors perform better than type IV monitors. Among the sleep questionnaires examined in this review, only the Berlin Questionnaire was deemed useful for predicting OSA risk.
Image: PD
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