Evidence Summary

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Continuous positive airway pressure (CPAP) devices and mandibular advancement devices improve sleep outcomes in people with obstructive sleep apnea

Qaseem A, Holty JE, Owens DK, et al. Management of Obstructive Sleep Apnea in Adults: A Clinical Practice Guideline From the American College of Physicians. Ann Intern Med. 2013;159:471-83.

Review question

Which treatments are effective for obstructive sleep apnea?


Obstructive sleep apnea is a condition in which breathing stops and starts repeatedly during sleep. This happens because the tongue and throat muscles relax during sleep and the airways become temporarily blocked or narrowed. Symptoms include loud snoring and feeling tired during the day, even after a full night's sleep.

Treatments used during sleep include continuous positive airway pressure (CPAP) devices and dental devices. CPAP provides a steady air flow at a specific pressure to prevent the airways from closing during sleep. The air is delivered through a mask placed over the nose. Dental devices, such as mandibular advancement devices, fit over your teeth and hold your jaw forward. Other treatments include weight loss, surgery, and medications.

How the review was done

The researchers did a systematic review, searching for studies published up to September 2010. They found 132 randomized controlled trials and 23 other studies.

People in the studies were more than 16 years of age and had obstructive sleep apnea, with an apnea-hypopnea index (AHI) of at least 5 events per hour measured during a formal sleep study. The AHI is the number of episodes of stopped breathing (apnea) and reduced breathing (hypopnea) per hour of sleep.

The treatments assessed were CPAP devices, dental devices, weight loss, surgery, or medications. They were compared with control (no treatment or sham treatment) or each other.

The outcomes were AHI and the Epworth Sleepiness scale (questions about the likelihood of dozing in 8 everyday situations; answers are added up for a total sleepiness score), and quality of life.

What the researchers found

CPAP and mandibular advancement devices each reduced AHI and the sleepiness score more than control, but CPAP reduced AHI and the sleepiness score more than mandibular advancement devices.

CPAP and mandibular advancement devices did not improve quality of life.

There was insufficient evidence to assess the effects of surgery or medications.

Weight loss improved AHI more than control groups.


In people with obstructive sleep apnea, CPAP devices improve sleep measures more than mandibular advancement devices. CPAP and mandibular advancement devices both improve sleep measures more than control groups receiving no treatment or sham treatment.

Effect of treatments for obstructive sleep apnea in adults


Number of trials

Effects of treatment

Quality of the evidence

CPAP vs control

43 trials

CPAP reduced AHI and sleepiness score


Mandibular advancement devices vs control

10 trials

Mandibular advancement devices reduced AHI and sleepiness score


CPAP vs mandibular advancement devices

10 trials

CPAP reduced AHI more than mandibular advancement devices; results for sleepiness scores were inconsistent


Weight loss vs control

3 trials

Weight loss reduced AHI; sleepiness score was not reported


Medication vs control

7 trials

Insufficient evidence to assess effect


Surgery vs control, CPAP, or mandibular advancement devices

20 trials

Insufficient evidence to assess effect


AHI = apnea-hypopnea index: the number of episodes of apnea (completely blocked airflow) plus the number of hypopneas (reduced airflow) per hour of monitored sleep. Control groups received no treatment or sham treatments.

Related Topics


Control group
A group that receives either no treatment or a standard treatment.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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