Treatment for Sleep Apnea in People without Symptoms

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The summary below is from the full report titled "Treatment with Continuous Positive Airway Pressure Is Not Effective in Patients with Sleep Apnea but No Daytime Sleepiness. A Randomized, Controlled Trial." It is in the 5 June 2001 issue of Annals of Internal Medicine (volume 134, pages 1015-1023). The authors are F Barbé, LR Mayoralas, J Duran, JF Masa, A Maimó, JM Montserrat, C Monasterio, M Bosch, A Ladaria, M Rubio, R Rubio, M Medinas, L Hernandez, S Vidal, NJ Douglas, and AGN Agustí.

What is the problem and what is known about it so far?

During sleep, some people stop breathing for short periods, a condition known as sleep apnea. This partly awakens them and prevents them from achieving normal, restful sleep. Many people with sleep apnea feel bad, have difficulty thinking clearly, and suffer from daytime sleepiness. These symptoms can be troublesome, or even dangerous (if, for example, the affected person falls asleep while driving a car). The usual treatment for this problem involves wearing a special mask during sleep that uses air pressure to keep the breathing passages open (continuous positive airway pressure, or CPAP). This mask can reduce or eliminate the daytime symptoms, but the treatment is expensive and often annoying. Some people with sleep apnea do not complain of sleep-related symptoms, but they may still have trouble thinking or tend to fall asleep even though they are not aware of those problems. It has been suggested that all patients with sleep apnea be treated with CPAP, whether or not they complain of daytime sleepiness. It is not known, however, whether CPAP treatment actually benefits patients without daytime sleepiness.

Why did the researchers do this particular study?

To find out whether CPAP treatment helps people with sleep apnea who do not complain of daytime sleepiness.

Who was studied?

The researchers studied 55 men and women with sleep apnea but no or only mild daytime sleepiness.

How was the study done?

Study participants were chosen randomly to use either a real CPAP mask that delivered the pressure treatment or a mask that looked like the working mask but delivered no pressure. Participants were asked about their quality of life and daytime sleepiness before treatment was started and after 6 weeks of treatment. Blood pressure and mental function (including attention, memory, and coordination) were also measured before and after treatment.

What did the researchers find?

On average, both groups used their masks for about the same number of hours each night. After 6 weeks of treatment, patients who had real CPAP and those who had sham CPAP did not differ in quality of life, daytime sleepiness, mental function, or blood pressure.

What were the limitations of the study?

It is harder to prove that a treatment has no effect than to prove that it does have an effect, particularly in a small study. The methods for measuring mental function might not have been sensitive enough to pick up actual differences between the groups.

What are the implications of the study?

Treatment with CPAP does not appear to be helpful in patients with sleep apnea who have no or only mild symptoms of daytime sleepiness.