[News] Washington Post Article

[Sleepster]

This WAPO article has a title that grabbed my interest and challenged my beliefs. But in the fifth paragraph from the end the challenge seems to disappear with this comment:

One possibility raised in both the study and an accompanying editorial is that the CPAP group was able to wear the masks only about 3.3 hours per night, a duration that is consistent with CPAP users in the real world.

How the heck can 3.3 hours of use per night be expected to do anything other than prolong the agony of a sleep-deprived life! And what real world is it that they're living in? It sure ain't the same one I'm in.

CPAP machines don’t prevent heart attacks, strokes in some sleep apnea sufferers

By Lenny Bernstein August 28

More than 25 million Americans have obstructive sleep apnea, a dangerous disorder that causes sufferers to briefly stop breathing while they sleep, sometimes many times each night. The condition, caused by throat muscles that relax and block the airway, has been linked to heart disease, high blood pressure, strokes and Type 2 diabetes.

The standard treatment, using the continuous positive airway pressure, or CPAP, machine, keeps the airway open by pumping a stream of air through the nostrils as a person sleeps. The biggest problem with the therapy is noncompliance; many people find the air mask and hose uncomfortable and give up on the machine.

But a large study published Sunday raises a serious new issue: For people with existing cardiovascular disease and moderate to severe sleep apnea, CPAP doesn’t prevent heart attacks, strokes, hospitalizations or deaths any better than sleeping without the machine.

The finding surprised scientists from two Australian research institutes who conducted the research, because previous examinations have shown that CPAP seemed to have a positive impact on those problems.

In earlier studies, “the epidemiological data is very strong and the biomarker data is very strong,” said Craig S. Anderson, a professor of stroke neurology at the George Institute for Global Health in Sydney, and one of the leaders of the new study. So too is observational research on subjects who use CPAP machines, he said.

Virend Somers, a professor of medicine at the Mayo Clinic in Rochester, Minn., who was not involved in the research, called the new study “a very important paper” because it provides the first large, randomized, controlled look at CPAP benefits that were only previously assumed.

CPAP is far from worthless, according to the new research, which was published in the New England Journal of Medicine and presented at a cardiology conference in Rome Sunday. The five-year study of people in seven countries confirmed that the pump reduced the daytime sleepiness that plagues sleep apnea patients, with corresponding improvements in mood, quality of life and work productivity. It also reduced sufferers’ anxiety and depression somewhat.


The study was by far the largest to look into obstructive sleep apnea, Anderson said. It involved 2,687 subjects between the ages of 45 and 75.

When the researchers divided the participants into two roughly equal groups, they found that CPAP had no impact on heart attacks and strokes, nor from deaths from any cause or hospitalization for heart failure, unstable angina and other reasons.

It’s not clear why that might be, Anderson said. One possibility raised in both the study and an accompanying editorial is that the CPAP group was able to wear the masks only about 3.3 hours per night, a duration that is consistent with CPAP users in the real world. That may not be enough time to affect the frequency of these cardiovascular events. Or it may be that cardiovascular disease is too difficult to modify in this way once it develops, Anderson said.

Somers, the Alice Sheets Marriott professor of medicine and a consultant in cardiovascular disease at the Mayo Clinic, said he would like to know whether better adherence to the CPAP regimen might convey more long-term benefits. It’s unknown whether the adrenaline and blood pressure surges that come with taking off the mask and returning to an apneic state in the middle of the night are as harmful as sleep apnea itself, he said.

Although the researchers didn’t look at it, Anderson said it is probably safe to assume that sleep apnea sufferers who don’t have preexisting cardiovascular conditions would show similar results. But more research on that is needed, he said. Somers agreed.

However, he pointed out that patients who are most sleepy during the day were excluded from the study, because of the danger that they would be randomized to the group that wasn’t receiving CPAP and could hurt themselves or others in car accidents or in other ways. While it would be a difficult study to accomplish, Somers said, it could be important to know whether CPAP protects sleepy patients from cardiovascular events.

Sleep apnea is often but not always associated with increasing obesity, and many cases of sleep apnea remain undiagnosed. Common symptoms are loud snoring or gasping while sleeping.

[richb]

We have had considerable discussion on the subject of this flawed study referenced in the WA PO article. http://www.apneaboard.com/forums/Thread-...cpap-users In my opinion the conclusion of the study should have been that "non-compliant use of CPAP is no different than non use of CPAP among cardiac patients."

Rich

[Sleepster]

Thanks. I missed that one!

[theone]

This sure make you wonder..

[NorthernGuy]

I haven't read the scientific article, just the news story, but it seems like weak science.

How can the authors call using the CPAP use of ~3.3 hours a night "CPAP treatment" and compare that entire group to untreated? The authors should have only included successfully treated (say AHI <= 5) and >= 4 hours per night usage in the successful CPAP group. The successfully treated CPAP pool should have been compared to untreated known sleep apnea patients for the purpose of a study. Otherwise it is like comparing drugs where one group only takes half of the doses (or less).

My guess is that the study pool size was became too small for the statistical power they needed, so they enlarged the pool to all CPAP users (successful or not).

If I am missing something, then please speak up and correct me.

[Maskup N. Sleepwell]

You hit the nail on the head RichB ... "non-compliant use of CPAP is no different than non use of CPAP among cardiac patients."

Can't say I'm surprised.

[stephengreene]

I understand that 3.3 hours of CPAP usage provides no benefit. Does anyone know what is the minimum usage that will provide a benefit?

[richb]

I understand that 3.3 hours of CPAP usage provides no benefit. Does anyone know what is the minimum usage that will provide a benefit?

Hi stephengreene. Welcome to the Apnea Board. Most insurance and Medicare require a minimum of 4 hours per night usage to be compliant with treatment. That does not mean that 4 hours is sufficient for reasonable benefit. Going nearly half a nights sleep without therapy could result in frequent O2 desaturations. Why would anyone even want to subject themselves to that. For most of us the goal is to use our machines while we are sleeping. That is when Obstructive and Central Apneas happen. I think that the insurance industry including Medicare picked a number that they can live with when evaluating compliance from new patients. It takes time for new CPAP users to get used to their treatment. Mask and sometimes pressure issues take time to sort out. If I were to design a study it would be with people who use the machine for their entire nights sleep. Given that finding subjects might be difficult I would allow a minimum of 6 hours per night be a mimimum. I would also select people who had been using xPAP for at least 3 months. I would compare that to a non compliant control group and a diagnosed with apnea but untreated group. Rich

[chill]

Plus, minimum usage will provide minimum benefit. Why bother? It is like asking how seldom you can brush your teeth and still get fewer cavities than if you never brushed at all?

I've not seen any research indicating that the 4 hour compliance about is about therapy benefits. As Rich said, they needed to draw a line between people who were not going to use the machines long term and those who probably would.

[stephengreene]

Thanks for the response. Is there some scientific study that indicates 6 hours will provide benefit? Your answer sounds like a "best guess" but it is unclear that there is medical proof to support this. I am coming up to my annual checkup and would hope the results will show some benefit for my efforts. But unclear how to measure that.