Sleep apnea: what it is, treatment and tirzepatide

Complete guide: GLP-1 drugs: a complete guide to semaglutide and beyond

What is obstructive sleep apnea and how many people have it?

Obstructive sleep apnea (OSA) is a disorder in which the upper airway repeatedly collapses during sleep, causing complete (apnea) or partial (hypopnea) pauses in breathing accompanied by oxygen drops and brief arousals¹³. It is quantified with the apnea-hypopnea index (AHI): the number of events per hour of sleep. The usual thresholds are 5 or more events per hour for any degree and 15 or more for moderate to severe disease¹.

A 2019 estimate in Lancet Respiratory Medicine calculated that 936 million adults aged 30 to 69 have mild to severe OSA and 425 million have moderate to severe OSA, with the largest number of cases in China¹. Reliable data came from only 16 countries, so the figure is a model, not a census¹. In 1993, the Wisconsin cohort had already described how common the disorder is in middle-aged adults¹⁷, and a later analysis of that cohort found that prevalence of moderate to severe disease had increased².

Body weight is the most studied modifiable factor. In the Wisconsin cohort, a 10% weight gain predicted an increase of about 32% in AHI, and a 10% loss predicted a decrease of about 26%⁸. A 10% weight gain was associated with a six-fold higher odds of developing moderate to severe OSA⁸.

Symptoms and how sleep apnea is diagnosed

The most characteristic symptoms are snoring, breathing pauses witnessed by a partner, unrefreshing sleep and daytime sleepiness³.

The AASM diagnostic guideline states that testing should be done within a comprehensive sleep evaluation and that polysomnography is the standard diagnostic test for adults with suspected OSA³. The same guideline recommends against relying on clinical tools or questionnaires alone to diagnose the disease without an objective test³.

The AHI has known limits: it counts events but does not capture how long or how deeply oxygen falls. That is why other measures are being studied, such as hypoxic burden, which summarizes the area of desaturation linked to respiratory events¹⁶.

Standard OSA treatment today

First-line treatment is continuous positive airway pressure (CPAP). The 2019 AASM guideline recommends starting positive airway pressure in adults with OSA and excessive daytime sleepiness⁴. Its main limit is adherence: in SAVE, the CPAP group used the device an average of 3.3 hours per night, and the AHI fell from 29.0 to 3.7 events per hour during follow-up⁵⁶.

Other options include weight loss, mandibular advancement devices and surgery. Hypoglossal nerve stimulation was tested in a multicenter single-group study of 126 participants who had difficulty accepting or adhering to CPAP: the median AHI fell 68%, from 29.3 to 9.0 events per hour, at 12 months⁷.

On weight loss, an Australian randomized trial of 60 people with obesity compared a conventional program with bariatric surgery: the AHI fell by 14.0 events per hour in the conventional group and 25.5 in the surgical group, although the between-group difference was not statistically significant (P = 0.18)⁹. In Sleep AHEAD, an intensive lifestyle intervention lowered the AHI by 9.7 events per hour more than education at 1 year, but the difference at 10 years was 4.0 events per hour and not significant¹⁰.

One result worth keeping in mind: in SAVE, CPAP plus usual care did not reduce cardiovascular events compared with usual care alone (17.0% versus 15.4%; hazard ratio 1.10; 95% confidence interval, 0.91 to 1.32) in 2,717 adults with coronary or cerebrovascular disease, although it did improve snoring, sleepiness and quality of life⁵.

What peptide research has shown: tirzepatide and liraglutide

Tirzepatide. A synthetic peptide that activates both the GIP and GLP-1 receptors (more in Tirzepatide mechanism of action: GIP, GLP-1, the paradox). SURMOUNT-OSA consisted of two phase 3, double-blind, randomized trials in adults with moderate to severe OSA and obesity: trial 1 enrolled people not using positive airway pressure and trial 2 those who were¹². Participants were assigned tirzepatide at the maximum tolerated dose (10 or 15 mg) or placebo for 52 weeks¹².

At baseline the mean AHI was 51.5 events per hour in trial 1 and 49.5 in trial 2, with a mean body-mass index of 39.1 and 38.7¹². At week 52 the AHI had changed by -25.3 events per hour with tirzepatide versus -5.3 with placebo in trial 1 (estimated difference -20.0; 95% confidence interval, -25.8 to -14.2), and by -29.3 versus -5.5 in trial 2 (difference -23.8; 95% confidence interval, -29.6 to -17.9)¹². Body weight, hypoxic burden, high-sensitivity C-reactive protein, systolic blood pressure and patient-reported outcomes also improved¹².

The FDA approved tirzepatide on December 20, 2024 for moderate to severe OSA in adults with obesity, to be used with a reduced-calorie diet and increased physical activity; the approval rested on two studies of 469 adults without type 2 diabetes¹⁵. It is the only peptide indication for this disease documented here. For weight context, the SURMOUNT-1 trial evaluated tirzepatide in obesity more broadly¹³.

Liraglutide. A smaller signal was seen with another GLP-1 agonist. In the SCALE Sleep Apnea trial, 359 adults with obesity and moderate or severe OSA who were unwilling or unable to use CPAP received liraglutide 3.0 mg or placebo for 32 weeks, along with diet and exercise: the AHI fell by 12.2 versus 6.1 events per hour (difference -6.1; 95% confidence interval, -11.0 to -1.2) and weight by 5.7% versus 1.6%¹¹. The authors also observed an association between weight loss and OSA improvement in a post hoc analysis¹¹. The sources consulted did not verify an OSA indication for liraglutide.

Safety: adverse effects and precautions

In SURMOUNT-OSA, the most frequent adverse events with tirzepatide were gastrointestinal and mostly mild to moderate¹². The FDA lists as common effects nausea, diarrhea, vomiting, constipation, abdominal discomfort and pain, injection site reactions, fatigue, allergic reactions, burping, hair loss and gastroesophageal reflux disease¹⁵.

The FDA also warns of a risk of thyroid C-cell tumors: tirzepatide caused them in rats and it is unknown whether it does in humans; it should not be used with a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2¹⁵. Other warnings include pancreatitis, gallbladder problems, hypoglycemia, acute kidney injury, diabetic retinopathy, suicidal thoughts and pulmonary aspiration during general anesthesia or deep sedation¹⁵. More on tolerability in Tirzepatide side effects: what the trials show.

Summary by agent

Frequently asked questions

Is tirzepatide approved for sleep apnea? Yes, the FDA approved it on December 20, 2024 for moderate to severe OSA in adults with obesity, alongside a reduced-calorie diet and more physical activity¹⁵.

Does it replace CPAP? No evidence establishes that. Trial 2 of SURMOUNT-OSA enrolled people already using positive airway pressure, and the AASM guideline still recommends positive airway pressure in adults with OSA and excessive daytime sleepiness⁴¹².

How much did the apnea-hypopnea index fall in the trial? Over 52 weeks, by 25.3 events per hour in trial 1 and 29.3 in trial 2, versus 5.3 and 5.5 with placebo¹².

What happens if treatment is stopped? In the SURMOUNT-4 obesity trial, people switched from tirzepatide to placebo regained weight (+14.0% change between weeks 36 and 88), whereas those who continued maintained or extended their loss¹⁴. That trial did not measure apnea, so the effect on AHI after stopping cannot be read from it.

Does losing weight improve sleep apnea? Yes, proportionally: a 10% weight loss predicted a 26% lower AHI in the Wisconsin cohort⁸. However, the effect of lifestyle interventions faded by 10 years in Sleep AHEAD¹⁰.

Does CPAP prevent heart attacks and strokes? In the SAVE trial it did not in people with established cardiovascular disease, although average use was 3.3 hours per night⁵.