These are activities that expand general practice knowledge, skills and attitudes, related to your scope of practice.
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These are activities that use your work data to ensure quality results.
These are activities that expand general practice knowledge, skills and attitudes, related to your scope of practice.
These are activities that require reflection on feedback about your work.
These are activities that use your work data to ensure quality results.
CPAP is currently the gold standard for managing moderate to severe obstructive sleep apnoea, but compliance is low and evidence for its long-term benefits is limited. With obesity a major OSA risk factor, new weight loss interventions could lead to better outcomes—but we probably won’t be throwing away the CPAP machines, experts say.
Research clearly shows weight loss resulting from surgical, medical or lifestyle interventions can improve obstructive sleep apnoea in people with overweight/obesity, notes respiratory and sleep physician Professor Brendon Yee, Senior Staff Specialist at Royal Prince Alfred Hospital, Head of Sleep Medicine at the University of Sydney and senior research clinician at the Woolcock Institute of Medical Research.
As a rule of thumb:
“And there may be a plateau effect after around 20 per cent weight loss. However, there is a lot of individual variability with weight loss and improvement in OSA.”
Losing weight improves OSA by enlarging the upper airways and reducing their collapsibility, he explains, and via changes to lung volumes.
However, weight loss is notoriously hard to achieve and maintain.
While sleep physicians advise patients with OSA who are overweight or obese to lose weight as a matter of course, many patients have already tried and failed, notes sleep physician Dr Anup Desai, Senior Staff Specialist at Prince of Wales Public Hospital and Director of the Sydney Sleep Centre and St Luke’s Private Hospital Sleep Laboratory.
“I personally am not always that optimistic about their weight loss. So I usually encourage patients to do another treatment in the meantime,” he says.
Professor Yee agrees.
“In the real world, most patients are treated if they’ve got sleep apnoea with mechanical therapies such as CPAP,” he says. “And weight loss, although recommended by us as sleep physicians, is ideal but generally difficult to implement.”
This could change with the advent of drugs that lead to clinically significant weight loss, particularly the latest GLP-1 receptor agonists.
With dual receptor agonist tirzepatide (Mounjaro), for example, “you probably get about a 19% reduction in BMI and weight,” Professor Yee says.
Recent research also indicates these drugs may specifically improve OSA.
The SURMOUNT OSA phase 3 study, for example, consisted of two trials in patients with moderate-to-severe OSA and obesity: those in trial one were already using CPAP and those in trial two were not. Patients in each trial were randomised to receive either tirzepatide or placebo over 52 weeks, combined with a calorie-restricted diet and physical activity.
By the end of the study, patients using tirzepatide in trial one had 25.3 fewer apnoea/hypopnea events per hour during sleep on average than they did at baseline, compared to 5.3 fewer with placebo. In trial two, tirzepatide patients had 29.3 fewer apnoea/hypopnea events per hour on average than at baseline, compared to 5.5 fewer in the placebo group.
Approximately 50% of patients in the tirzepatide group in trial two were effectively cured of their sleep apnoea, Professor Yee adds.
“Their apnea-hypopnea index was less than 5, which is normal, or was less than 15 with no symptoms of daytime sleepiness,” he explains.
“So what we call a medical cure of the obstructive sleep apnea. So up to 50% of patients who would normally be prescribed CPAP you could basically say to them, you don’t really need CPAP.”
Mounjaro was recently TGA approved for chronic weight management in adults with a BMI of 27 kg/m2 or more and at least one weight-related comorbidity, such as OSA.
“These medications open up the possibility of us being more aggressive about weight loss, which is quite exciting,” Dr Desai says.
Probably not.
CPAP is a validated treatment, Professor Yee notes. “It improves symptoms of sleepiness, improves symptoms of snoring, and it probably improves sleep quality as well.”
“We know that it doesn’t have any major side effects.”
CPAP works “incredibly effectively” for the vast majority of suitable patients, adds Dr Desai. “It will reduce their apnoea index—which is the current measure of severity—to less than five, which is normal.”
But neither is CPAP alone the ‘holy grail’ of OSA treatment, Professor Yee says.
“It’s always a mask and always a machine. We also know compliance with CPAP is not as good as one would hope,” he says, citing a French national registry which found a CPAP dropout rate of almost 50% after three years.
Dr Desai agrees compliance is an issue but stresses it can be improved by picking the right patients, “particularly the more severe ones that are more symptomatic.”
“If you put CPAP on someone that’s got mild apnoea or they’ve got no tiredness or sleepiness, they often won’t continue it because they’re not feeling any benefit,” he says.
Good education about why they are using it can also aid compliance, he says.
Another issue with CPAP is the lack of randomised controlled trials (as opposed to observational studies) showing benefits for mortality or cardiovascular events, Professor Yee says.
“If they’ve got a lot of obesity-related comorbidities, then CPAP will not have a major benefit with respect to that.”
In contrast, weight loss has been shown to improve physical function, cardiovascular risk, and obesity-related complications such as type 2 diabetes, fatty liver disease, osteoarthritis, and heart failure with preserved ejection fraction, Professor Yee notes.
“And there was a recent paper published showing that there’s a 20% relative risk reduction in composite death from cardiovascular causes in patients who are randomised to a GLP-1 agonist versus placebo over 40 months.”
Dr Desai says weight loss is “by far the best single intervention for many people for many conditions,”–– including several linked to OSA such as impaired fasting glucose, diabetes, heart disease, and stroke risk.
Evidence that CPAP reverses these conditions is limited, in part because good quality studies are lacking, and in other studies CPAP compliance is poor. “And some of it might also be that perhaps CPAP isn’t quite as good at reversing these things as we would like to think. And there are ongoing studies to try to look at that,” Dr Desai says.
We also don’t know which OSA patients benefit most health-wise from CPAP therapy,
“The field’s aware of that. They’re trying to develop clearer subsets of people that might have different health outcomes that might benefit from different treatment approaches.”
“And there are some people with sleep apnoea that lose weight and their RDI [respiratory disturbance index – a measure of sleep apnoea severity] does not improve as much as the literature would show, too,” he notes.
New weight loss drugs also have their downsides.
They can cost hundreds of dollars per month and are not currently funded under the PBS.
“That’s going to be a problem moving forward for many patients,” Dr Desai says. “It might lead to reduced compliance or shorter courses of treatment.”
No major adverse events were reported in the SURMOUNT-OSA trial, and “discontinuation was probably about 5 to 7%,” Professor Yee says.
“I think the caveat though is the slow titration of the tirzepatide dose during the trial with appropriate support.”
Dr Desai says GI side effects are the most common and affect about 10 to 15% of patients. “And that’s going to mean some people will stop treatment.”
“We don’t know how long people should be on them, but we do know that if they stop it, they regain a lot of the weight,” Dr Desai says.
“If they stop it at three months, do they gain 75% of the weight back? And have we really done them a good service?” he asks.
Muscle and bone loss can also occur, Professor Yee notes, “and I think the benefits of having concomitant exercise programs should not be underestimated.”
Deciding who will prescribe and manage the medications is another issue, Dr Desai says, stressing patients need regular follow up to monitor side effects and adjust dosages of other drugs as needed.
Sleep specialists could also face liability issues if the sleep apnoea itself is not adequately managed while patients are losing weight.
“So I think there needs to be more discussion between specialists and GPs about how are we going to manage this.”
Professor Yee agrees, noting people see a specialist for OSA rather than weight loss per se.
“This is something that we don’t normally deal with. We tell patients to lose weight, we give them information, but we don’t prescribe medications for the weight loss because we’re respiratory or sleep specialists. We will need more training and experience with these medications if we decide to prescribe them.”
The optimal approach probably involves a combination of interventions, Dr Desai says, noting sleep physicians already use oral appliances and positional therapy as well as CPAP.
“It may be quite effective to use these medications to help achieve that combination approach, knowing that maybe they’ll gain some of that weight back if they stop them, but we’re not relying just on the medication.”
“We need to have other treatments while they’re working on the weight loss, and that way we can keep monitoring them and maybe retesting them down the track.”
Professor Yee also thinks a combination of interventions is probably best.
“If you want a treatment for your snoring and daytime sleepiness within the short term, CPAP’s very effective for that if you can get used to it, while the weight loss would be something you do over a period of time that will reduce the chance of developing cardiometabolic complications if you have OSA and are obese or overweight,” he says.
“And some evidence suggests that a combination of CPAP plus weight loss may have better outcomes.”
Ideally, management would involve input from a multidisciplinary team including sleep physicians, obesity experts, nurses, dietitians and exercise physiologists, he adds.
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