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Polysomnography: To a Hammer, Does Everything Look Like a Nail?
#1
Right off the bat, I'd like to state for the record that I would concur that if anything, most evidence points to Sleep Apnea being widely underdiagnosed.

That said, I wonder if there are any statistics on the percentage of people who undergo 
polysomnography who end up being told they do not have apnea. By the nature of the type of patients referred to a sleep study, of course, the percentage of those ending up with a positive diagnosis will more likely be significantly higher than in the general population. Most of us who were sent for a sleep study were there because we had, signs, symptoms and/or risk factors.

But I wonder if a control group were sent for a polysomnography, what the positive vs. negative diagnosis ratio would be, and if any double blind studies have ever been done along those lines. Thinking-about
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#2
If anything, what I have noticed is that everyone with apnea and hypopnea are diagnosed as having "obstructive apnea" regardless of whether the evidence shows central events or not.  That is just the diagnostic test.  In titration, nearly all patients are prescribed CPAP at a single pressure, even when the sleep study shows inconsistent results or multiple pressures that might be effective, and the effect of EPR/Flex is almost never investigated.  Why do so many people end up on this forum with the inability to sleep, and having large numbers of events?  Or for that matter, why do so many people that don't end up here fail at the therapy?  

As your thread title accurately implies, all apnea is treated the same, as obstructive.  For some reason, doctors think that if something is not working, they can just throw more pressure at it, or treat it with BiPAP (which makes centrals worse).  It's a wonder to me. Dont-know
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#3
I had the opposite experience.  I was originally diagnosed with hypopnea and an AHI of 10 (IIRC).  I was told to lose weight, exercise more, and reduce my alcohol consumption. The spectator of "if you don't do this, you will end up on a CPAP machine which is almost worse than death" was soundly enforced.  Seven years later, I love my CPAP machine and wish that I had it seven+ years ago.
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#4
I have multiple health issues. In all but one of them, treatment is firmly based on documented, measurable evidence. I have my blood pressure closely watched. My A1c closely watched. Treatment for both are based on those numbers. If we must shift medications, we do. Xrays and CT scans determine the skeletal needs and treatment. Then are redone on a regular basis to see if that treatment is working. Etc etc.

All but my sleep apnea. Two sleep tests (they did not do a split study but had me come in twice), what, 12 yrs ago?
Doc set the brick to 8.
Three months later, changed it to 10. Based on what? Nothing. I had a brick.
Years later I went through a blood pressure scare. Horrendously high BP to the point they were afraid I'd stroke. Had cath done. Had stress test done. Heart seemed fine. Finally heart doc said "let's consult your sleep doc". Using a single night's worth of oximeter test, he raised it to 12. That's it. BG goes down, sure, but I still think it was a lucky guess on his part.

All of that heart scare (and expensive tests) could have been avoided if I had a data-capable machine. My AHI must have been high to cause my BP to jump like that.

The sleep doc doesn't like autoPAPs. Doesn't think I need to see the data.

Not been back to him since. I got an autoset out of pocket and haven't bothered to go back. To him, it isn't hammer and nail, it is magic from his god-like mind.
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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.




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#5
(10-12-2017, 08:47 PM)Sheepish Wrote: Right off the bat, I'd like to state for the record that I would concur that if anything, most evidence points to Sleep Apnea being widely underdiagnosed.

That said, I wonder if there are any statistics on the percentage of people who undergo polysomnography who end up being told they do not have apnea. By the nature of the type of patients referred to a sleep study, of course, the percentage of those ending up with a positive diagnosis will more likely be significantly higher than in the general population.

But I wonder if a control group were sent for a polysomnography, what the positive vs. negative diagnosis ratio would be, and if any double blind studies have ever been done along those lines. Thinking-about

There are a number of issues to running a controlled study as you have described: one, most people referred for a sleep study already have a chief complaint and/or comorbidities; two, a more general screening of the population may be prohibitive due to sample size, cohort stratification, and cost.

However, the we can glean some generalizations from the following two studies: "Polysomnography in Patients With Obstructive Sleep Apnea: An Evidence-Based Analysis" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3379160/ and

The Epidemiology of Adult Obstructive Sleep Apnea https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2645248/ where Table 1 is probably closest to providing the information you seek. (Remember, the statistical inferences from such small sample sizes when projected onto a global population may be invalid). According to Table 1 data - you can subtract the prevalence percentage from 100% and assume that this might generally represent that percentage of the population (test group) who do not have diagnosed sleep apnea based on polysomnography.

This is not a type of study for a true double-blind study where neither the subjects nor the experimenters know which subjects are in the test and control groups during the actual course of the experiments because it would be assumed that "all" are equally likely to have apnea and patients are considered negative until the test is started and the experimenter can see preliminary data. 

Hope this helps.
"The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." -- Marcus Aurelius
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#6
Guess I've got the familiar story on Apnea and CPAP,  but what do I know. I started on a CPAP with an over 70 AHI and CPAP set to 18, even though the doc scripted 20. That DME correctly assumed I'd not handle the setting of 20. Still, I couldn't get used to the "high" pressure and failed the compliance, returning the CPAP; that was 2015. Took 2016 to get weight down via bariatric sleeve surgery; successfully down 100 pounds and roughly halved the AHI. This year, onto BiPAP, where Duck doc scripts for my worst PSG results as GOOD on the BiPAP; that caused it's own troubles in the form of Central Apnea and therefore actually mixed apnea. Ten rounds with the Mike Tyson of doc missing proper words on the new ASV script and the DME not getting info to insurance dufus dance. But hey the square peg got forced thru the round hole. I'm on ASV. Woohoo! And still alive to tell y'all about it too.
Due to my sarcastic nature, it may not be obvious that I am not a doctor nor do I pretend to be one. My advice is from personal experience. Follow my advice as a choice not as an order. 2 of these  Coffee Coffee per day keep the bad times away.
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#7
Interesting question.

No doubt about it the field of sleep medicine has grown since the early days, when sleep apnea was considered rare. 

One of the issues rarely mentioned when doctors and the media talk of the "explosion" of rate of sleep apnea is how the definitions have changed over time, along with  more sensitive equipment, so that many more are being diagnosed. Basically depending on which definition is used for hypopnea rates of sleep apnea can vary widely, it is quite staggering.

So patients need to be aware of which standard the lab is using to identify hypopneas in particular. 

Here's an interesting article on this subject published in 2015, and reflecting some of the contemporary issues. In this field any older studies i.e from even 10 years ago do not reflect the current prevalence because definitions have changed since then for diagnosis. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667391/

Here's an article discussing the study linked to above and raising some interesting issues about how events are scored these days. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667388/
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#8
Well, I would like to see how it is diagnosed these days over here.
When I went to the doctor after my partner said I stopped breathing when I was asleep, we mentioned Sleep Apnea/Apnoea to the doctor and was told "No one has ever died or will ever die of Sleep Apnoea."  this caused my partner to go on the attack, I think he was a bit scared of her when she exploded, as he started to look through a book.  He then said after she threatened him if he didn't do something she would put in a complaint.  This got a sarcastic response "I am the senior partner in the practice so you will only be complaining to me"
"Did I say I was going to complain to you?  No, it will go to the medical board."
This prompted him to arrange for a visit to the hospital and the Ear Nose and Throat department!  Why there I hear you ask?  It was because it was linked to the Chest Clinic at the hospital, this was where I saw the only doctor that was looking into Sleep Apnea in this area.  He did a test with a computer and an APAP connected to the computer to read the results.  This was in the early days here, longer than I care to admit!
Anyway, this led me to going to one of the main hospitals here and to see the Professor that was studying it here.
Got a half and half test (half to see if I did have Sleep Apnea and the other half to work out the pressure I needed.
After the test I saw him in the morning and he looked at the results and he did say there was a central apnea there, but he was not worried about it at the moment.  He also said I went into shallow breathing during the night,  so he at least was taking note.  He also said I slept in the same position almost all night.  He said that he only dealt with simple cases here and any others that was picked up had to go across country to another hospital where they dealt with all the problem sleeping disorders, Narcolepsy being one of them.  So I can only say that not all doctors deal with things in the same way.  That being said, I hear only to often that people are told they have Sleep Apnea and handed a machine and a mask and told to get on with it.
My mate, I heard him breathing and it just got slower and shallower until he stopped breathing, then when his brain decided he was not breathing woke him and his tongue had then fallen back into his throat, so there was the cough and splutter as he woke up.  He went to a hospital who gave him a machine, said he had Sleep Apnea and to go home and use the machine every night!  Shocking that they can give you a machine home not knowing if you are using it correctly or not, looking at what the machine says on the display, set up a machine with the pressure and send you home.
It was almost as if it was, Yes you have sleep apnea, here is a machine, use it and I will see you in a years time.
They never checked if he had central apneas, why his breathing slowed down then he stopped breathing or anything.  It was just Here is a machine, a mask, go away.  They never even tried any masks, they just stuck one on his face and said it was fine.  Shocking!
Maybe I was lucky in that I had one of two the leading people here, though the guy in the first hospital was fine, he just wanted to know if I was suffering from it or not before sending me away to one of the main hospitals to get sorted.  He made no bones about sending me away to another hospital.
Even so, when I went back and asked for a bit more pressure he increased it without much though about it.
I had it increased three times, he only asked why I wanted it increased, then did it.
Strange as he was so fussy when I was first diagnosed.   Dont-know 
Most doctors just think more pressure will fix everything.  Now they are handing out APAP machines to everyone, I wonder if they think that the APAP machines will take care of everything?  Nice though they are.
Being blown in the CPAP/APAP wind in   Undiscovered Bonnie Scotland
CPAP/APAP is a breath of fresh air!
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#9
I am in the UK and it’s not as good in my area.


I was diagnosed with sleep apnea 2 months ago after being referred to my local sleep clinic for a home sleep study.

I was issued with a brand new resmed S9 elite CPAP (Brick) set at 8.6 and told to come back in 30days and let us know how you are feeling my meeting was with 5 other users also being issued with the same CPAP device at various pressures and the nurse indicated they are handing out about 10 machines a week.

Off my own back I have purchased a Resmed Autoset 10 which has efficacy data and it has highlighted I have complex apnea. A typical night I have a treated AHI of 9 where 8.6 of that is centrals. Which looking at my sleep study with a now educated eye also shows an element of central apnea. So at my 28 day follow up I arrived with a pile of reports from resscan and asked what do I do now.... and how would you have known with the basic CPAP machine provided by yourselves. I am now waiting for an in hospital sleep study or a further meeting with the Doctor who I have not yet seen. Keep tuned but I could had I not been informed been on a CPAP machine that was not treating 60% of my AHI for the next many years, with no efficacy data nor a titration study how would the NHS of known ?...


Jason
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#10
After reading these shocking stories in this thread and hundreds more like these in other threads over the years it makes me appreciate more and more how valuable this board is.  What makes us all different here is that we are more typically not afraid to take control of our own situations and therapy.  What makes me cringe is the millions out there that are left to simply wallow in the mire.  Many die from OSA caused comorbidities.  

To the OP's point though I think a test for OSA should be given to everyone.  Do folks realize how many people die every year from tired and sleepy drivers with undiagnosed and/or untreated OSA?  It is better to have tested people with no OSA found than to not test those who would be found with OSA.  Therapy has advanced now to where the old time stigma should no longer apply.  Many stars and professional athletes have OSA and are on CPAP.  (As an example, the US professional football star Reggie White died from OSA and his wife started and continues a foundation in his name related to OSA.) Because stigma of therapy should no longer be an issue lets get more folks tested and treated.
Coffee

Happy Pappin'
Never Give In, Never Give Up


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. 
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