SURMOUNT-OSA — trial digest
SURMOUNT-OSA (N Engl J Med 2024): Does tirzepatide reduce the apnoea-hypopnoea index?
Citation and design
| Field | Value |
|---|---|
| Trial | SURMOUNT-OSA |
| Intervention | Tirzepatide up to 15 mg weekly |
| Publication | N Engl J Med, 2024 (first author Malhotra) |
| Design | Two double-blind, placebo-controlled trials, 52 weeks |
| Population | Adults with moderate to severe obstructive sleep apnoea and obesity, with and without positive airway pressure therapy |
This digest summarises the trial and the criticisms our journal club considered material. It is not a substitute for the paper, and where the two differ the paper is right.
The question it set out to answer
Does tirzepatide reduce the apnoea-hypopnoea index?
Stating the question before the result is a house convention. A great many arguments about this trial are actually arguments about what it was for.
What it found
Uses an objectively measured physiological endpoint rather than a symptom scale, which makes it unusually robust for this field.
Two parallel trials, differing in whether participants were using positive airway pressure therapy, which addresses the obvious confounder directly.
Reductions in the apnoea-hypopnoea index were substantial in both.
Criticisms the journal club considered material
- The apnoea-hypopnoea index is itself a surrogate for the outcomes people care about, such as daytime function and cardiovascular risk.
- Whether the benefit is attributable to weight reduction specifically or to something else is not resolved by these trials.
These are criticisms of the design and of how the result is used, not of the investigators. Sessions that lose that distinction get moderated.
How it is misused
The two recurring misuses of this trial in general discussion are quoting the relative effect without the absolute one, and extending the result to a population the trial did not enrol. Both are easy to correct and both keep happening.
Where a number appears in secondary coverage without an estimand attached, assume it is whichever version is larger and check the paper.
Maintenance
Digests are reviewed when new analyses of the same trial are published, and at the review date shown above regardless. If a secondary publication changes the picture, raise it in journal club rather than editing the digest directly, so the change is discussed before it lands.
Revision history
| 2026-02-26 | KTurkington | Added cross-references to the two topics that most often ask this question. |
| 2026-01-04 | revision_history | Corrected a unit label in the second table — it read mg where it should have read mg/mL. |
| 2025-10-14 | k.brandl_de | Added the limitations paragraph. The page previously implied more certainty than the sources carry. |
| 2025-06-13 | coldchain_liu | Initial promotion from the source topic. Structure taken from the marked solution. |
Every edit to a maintained document records its author and a note explaining the change. An edit without a note may be reverted by any wiki editor under R9, and the revert is logged. Disagreements about content belong on the source topic rather than in the revision history (R10).
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