Clinical Question: Does melatonin improve sleep in women with asthma?

Setting: Outpatient (any)

Study Design: Randomized controlled trial (double-blinded)

Allocation: Uncertain

Synopsis: This study included 22 women with mild to moderate asthma. During the first two weeks of the study, all of the patients received 1,000 mcg of inhaled beclomethasone every morning and could use inhaled albuterol as needed. At the end of this phase of the study, the investigators evaluated the patients’ sleep quality and daytime hypersomnolence. Next, they randomized the patients to receive 3 mg of melatonin (n = 12) or placebo (n = 10) every evening for 28 days. Patients and study personnel were unaware of treatment group assignment.

The primary outcome was global sleep quality using a 15-point scale, with a clinically meaningful difference being approximately 3 points or more. The authors did not mention whether they analyzed the data according to the original group assignment. The sleep quality scores for each group were similar at the beginning of the study. The patients treated with placebo had a mean decrease in their sleep score of 1.9 points, while those treated with melatonin had a mean decrease of 4 points. In other words, melatonin improved sleep by only 2.1 points more than placebo. Although statistically significant (i.e., the results are unlikely to be caused by chance), this is not a clinically meaningful difference. The finding is reinforced by a lack of improvement in daytime sleepiness.

Bottom Line: Melatonin improves sleep quality in women with asthma, but not in a clinically meaningful way. (Level of Evidence: 2b)