Sleep apnoea: the condition that qualifies you, if anyone looked

The airway closes during sleep. Not metaphorically — the soft tissue at the back of the throat loses tone, collapses inward, and air stops moving. Oxygen falls. The brain registers the emergency and surfaces you just far enough to restore muscle tone and reopen the airway, usually without waking you in any way you would remember. Then it happens again.

In moderate to severe disease this can occur dozens of times an hour, every hour, for years. The measure used is the apnoea-hypopnoea index — events per hour of sleep — and the cardiovascular consequence is not the snoring. It is the repeated drop in oxygen and the repeated surge of the stress response, several hundred times a night, which is why untreated obstructive sleep apnoea tracks with hypertension, arrhythmia, stroke and cardiovascular death rather than merely with tiredness.

Weight is involved in both directions, which is the part that makes it belong in this series. Fat deposition around the neck and pharynx narrows the airway and makes collapse more likely, and fat in the abdomen reduces lung volume in a way that makes the airway less stable. So weight gain worsens it mechanically.

And it runs the other way too. Fragmented sleep raises appetite, shifts appetite hormones, worsens insulin resistance and makes the next day harder in every respect that matters to body weight. The condition caused partly by weight then promotes it. That is a loop, and nobody enters a loop at a point of their choosing.

This is the section this post exists for, because the reporting made a reasonable reader believe something that is not true here.

In December 2024 the US Food and Drug Administration approved tirzepatide for moderate to severe obstructive sleep apnoea in adults with obesity, alongside a reduced-calorie diet and increased physical activity. It was the first medicine approved anywhere for the condition, which is a genuine milestone. Australia followed, with its regulator approving tirzepatide for OSA as the country’s first registered pharmacological treatment for it. The trials behind it, SURMOUNT-OSA, randomised 469 adults without type 2 diabetes across two studies — one in people using positive airway pressure, one in people unable or unwilling to use it — and the effect was substantial: in the non-PAP study, a mean reduction of about 27 events per hour at 52 weeks against roughly 5 on placebo.

All of which was widely reported, and in English, which means UK readers read it.

The UK label says something different. The Summary of Product Characteristics for Mounjaro carries two indications: insufficiently controlled type 2 diabetes, and weight management in adults at a BMI of 30 or above, or 27 to under 30 with at least one weight-related comorbid condition. There is no sleep apnoea indication. Obstructive sleep apnoea appears in that label in exactly one role — as one of the examples of a qualifying weight-related comorbid condition, listed alongside hypertension, dyslipidaemia, cardiovascular disease, prediabetes and type 2 diabetes.

The label then does something quietly revealing: section 4.1 directs the reader to section 5.1 for trial results on obstructive sleep apnoea. So the OSA data are in the British label. The indication is not. That is a regulator saying, in the only way a label can, that it has seen the evidence and has not granted the claim.

Two sentences that sound similar and are not:

A treatment licensed for your sleep apnoea. A treatment licensed for your weight, for which your sleep apnoea makes you eligible.

In the UK, only the second is available. And it matters in three practical ways.

It changes what you can ask for. Someone who arrives asking for treatment for their sleep apnoea may be told no, and may not understand why, because they read that it was approved. Someone who arrives saying they have obstructive sleep apnoea and want to be assessed for weight-management treatment is asking a question that can be answered yes.

It changes who pays and who prescribes. An indication determines what a prescriber can treat and what a system will fund. A qualifying comorbidity determines eligibility for a different treatment. Those travel through entirely different routes.

And it changes what you should expect to happen to the apnoea. Nothing in the UK label promises to treat it. What the evidence suggests, and what the label contains rather than claims, is that substantial weight loss tends to improve it. That is worth having and it is not a licensed indication, and the honest version of this is that your continuous positive airway pressure machine is not a thing to abandon on the strength of a weight treatment. Any change to apnoea treatment is a conversation with whoever manages your sleep apnoea, after a repeat sleep study, and not a conclusion to draw from the bathroom scale.

Here is the awkward arithmetic. Obstructive sleep apnoea is one of the conditions that qualifies someone for weight-management treatment between a BMI of 27 and 30. The large majority of obstructive sleep apnoea is undiagnosed. So a substantial number of people who are eligible cannot demonstrate it, and do not know there is anything to demonstrate.

It goes undiagnosed because its symptoms are read as something else. Daytime sleepiness gets attributed to a demanding job, or to age, or to being overweight in general terms. Morning headache, waking unrefreshed after eight hours, nocturia, irritability, difficulty concentrating, falling asleep in front of the television at nine — all of it is explainable by ordinary life, and all of it is also the symptom list. The snoring and the witnessed pauses in breathing are the obvious signs, and the person who has them is asleep. They get reported by a partner or they do not get reported.

Which makes this one of the few genuinely actionable things in this series: if several of those apply to you, a referral for a sleep study is worth asking for, and it is worth asking for whether or not weight treatment is on the table. Untreated moderate to severe sleep apnoea is a cardiovascular risk in its own right, and treating it changes how people feel more reliably and faster than almost anything else discussed on this site.

The eligibility is a bonus. The reason to find out is the condition.

Worth including because it is misunderstood in a way that discourages people.

Continuous positive airway pressure treats the apnoea mechanically: it holds the airway open with pressurised air, the oxygen dips stop, the sleep fragmentation stops, and for many people the difference in how they feel is dramatic and quick. It is a genuinely effective treatment for the condition.

What it does not do is cause weight loss. If anything the evidence points mildly the other way, and the reasons offered for that are undramatic — people who sleep properly are not necessarily people who eat differently, and energy expenditure during fragmented sleep is not lower in a way that the machine reverses. People who begin CPAP expecting the weight to follow are frequently disconcerted when it does not, and some conclude the machine is not working. The machine is working. It is treating the apnoea.

So the two interventions do different jobs, and in the group with both conditions they are not alternatives. CPAP treats the airway tonight. Weight loss addresses the mechanical cause over months. Doing one does not retire the other, and the sequence — treat the apnoea now, address the weight alongside — is usually the right way round, because the fragmented sleep that the machine fixes is itself making the weight harder.