Liraglutide 3.0 mg reduced sleep apnea events in 32-week trial

Adults with obesity and moderate or severe obstructive sleep apnea who were unwilling or unable to use continuous positive airway pressure (CPAP) therapy had 12.2 fewer apnea-hypopnea events per hour after 32 weeks on liraglutide 3.0 mg, compared with 6.1 fewer events per hour on placebo, according to the SCALE Sleep Apnea randomized trial ^[1].

The trial enrolled 359 people who did not have diabetes. They were randomly assigned to liraglutide 3.0 mg (180 participants) or placebo (179) for 32 weeks. Both groups also followed a diet with a 500-calorie-per-day deficit and an exercise program ^[1].

At the start, participants averaged 48.5 years old, 71.9 percent were men, and their average apnea-hypopnea index (AHI) was 49.2 events per hour. An AHI of 15 to 29.9 events per hour is considered moderate sleep apnea, and 30 or more is severe. About 67 percent of the participants had severe sleep apnea. Average body weight was 117.6 kilograms, average body mass index was 39.1, and 63.2 percent had prediabetes ^[1].

Over the 32 weeks, the average AHI reduction was larger with liraglutide than with placebo: minus 12.2 versus minus 6.1 events per hour. The estimated treatment difference was 6.1 events per hour (95 percent confidence interval, 11.0 to 1.2; P=0.0150) ^[1]. Liraglutide also produced greater average weight loss, minus 5.7 percent versus minus 1.6 percent (estimated treatment difference, 4.2 percent; 95 percent confidence interval, 5.2 to 3.1 percent; P<0.0001) ^[1].

A post-hoc analysis found a statistically significant link between how much weight a participant lost and how much their sleep apnea measurements improved (P<0.01) ^[1]. Reductions in glycated hemoglobin (HbA1c) and systolic blood pressure were also larger with liraglutide than with placebo (both P<0.001). The safety profile of liraglutide 3.0 mg was similar to that seen with doses of 1.8 mg or lower, the authors reported ^[1].

One detail matters when reading the numbers: the placebo group improved too. Those participants received an inactive injection along with the same diet and exercise support, and their AHI still fell by 6.1 events per hour ^[1].

Why it matters for patients

CPAP is a common treatment for obstructive sleep apnea, but this trial was designed for people who were unwilling or unable to use it ^[1]. For that group, the results show that a weight-loss medication can move a sleep apnea measurement substantially on average. An average change, however, does not predict what any one person will experience.

The results cover a single 32-week study. Whether the AHI change translated into less daytime sleepiness or better quality of life has not been reported in the published abstract ^[1], and longer-term effects on sleep apnea have not been reported either.

The trial tested liraglutide 3.0 mg at that specific dose, not semaglutide or tirzepatide, so the findings cannot be assumed to describe other GLP-1 or related medicines.

Liraglutide was not approved by regulators for the treatment of sleep apnea, so it is not a cleared option for that condition. The trial is research evidence, not a labeled use.

What happens next

No sleep apnea indication for liraglutide has been announced, and there is no dated milestone to watch on that front. The trial was registered as NCT01557166 ^[1]. People with sleep apnea and their clinicians are left with the same labeled options as before this trial was published.