AHI 4% calculation?

What does it mean in a sleep report when they do a AHI 4% calculation?

It was something that came up in a conversation when a friend told me her and her spouse were diagnosed with severe sleep apnea.

Any clue?

No - ask your friend what she meant (probably didn't understand it either).

Julie wrote: ↑

Tue Sep 18, 2018 10:26 am

No - ask your friend what she meant (probably didn't understand it either).

She's clueless and probably can't be bothered to call the clinic to ask what that means.

Terminology like that promotes misunderstanding.
See how well it works.

here's some talk about this-

viewtopic/t172988/AHI-3-vs-AHI-4.html

not sure if it's helpful.

zonker wrote: ↑

Tue Sep 18, 2018 11:10 am

here's some talk about this-

viewtopic/t172988/AHI-3-vs-AHI-4.html

not sure if it's helpful.

Thanks Zonker, that is exactly what I was looking for!

The discussion in that thread makes sense. In summation is would seem that an AHI 4% calculation underestimates the # of apneas/hyponeas b/c there would need to be a o2 desaturation of 4% or greater to be counted as part of the AHI calculation. I would conclude then that RAW AHI #'s are likely higher if you took o2 desaturations calcs out of the equation.

interesting stuff!

I came across this a while back and am still surprised by how utterly "unregulated" this field still is in some respects.
It would be like saying that you have different ways of determining if someone has hypertension. > 140/90 or >130/85, for example. Doctor gets to choose. Would any of us consider this good medicine?

Yet, in the world of sleep medicine this is how it has worked since around 2012 when the AASM rules for scoring for hypopneas changed.

https://aasm.org/aasm-clarifies-hypopne ... -criteria/

Two definitions can be used for scoring an hypopnea, and depending on which one is used you can be diagnosed with no OSA or moderate to severe OSA depending on the lab's scoring practices.

I read one example here about a year ago of someone who had an AHI of less than 5 when their PSG was scored using the 4% desat for hypopneas as per Medicare rules, and yet when scored under the 3% criteria this person's AHI was moderate at 18 events per hour. So, who decides if this person gets an XPAP prescription or not?

Go figure. It really is crazy.

Something is just not right. This needs much more scrutiny.

CPAPSteve wrote: ↑

Tue Sep 18, 2018 11:29 am

zonker wrote: ↑

Tue Sep 18, 2018 11:10 am

here's some talk about this-

viewtopic/t172988/AHI-3-vs-AHI-4.html

not sure if it's helpful.

Thanks Zonker, that is exactly what I was looking for!

The discussion in that thread makes sense. In summation is would seem that an AHI 4% calculation underestimates the # of apneas/hyponeas b/c there would need to be a o2 desaturation of 4% or greater to be counted as part of the AHI calculation. I would conclude then that RAW AHI #'s are likely higher if you took o2 desaturations calcs out of the equation.

interesting stuff!

happy to help! for some reason, the topic stuck in my head.

zonker wrote: ↑

Tue Sep 18, 2018 11:10 am

here's some talk about this-

viewtopic/t172988/AHI-3-vs-AHI-4.html

not sure if it's helpful.

And this is why it's a good thing for (especially new) people to read all the new topics on the board... this was just gone over *last week*.

palerider wrote: ↑

Tue Sep 18, 2018 1:11 pm

zonker wrote: ↑

Tue Sep 18, 2018 11:10 am

here's some talk about this-

viewtopic/t172988/AHI-3-vs-AHI-4.html

not sure if it's helpful.

And this is why it's a good thing for (especially new) people to read all the new topics on the board... this was just gone over *last week*.

completely missed this one. I normally lurk here each day catching up on new subjects but clearly I've missed this one.

Hey Steve, I appreciate seeing this topic being raised often, so no complaints here. It's worrisome that depending on which lab one goes to one might or might not be diagnosed ... it doesn't seem at all scientific or consistent.

Too many folks aren't aware that depending on scoring criteria used in their sleep study they might well get the short end of the stick. 4% vs 3% makes all the difference to getting treatment and a diagnosis.

CPAPSteve wrote: ↑

Tue Sep 18, 2018 1:17 pm

palerider wrote: ↑

Tue Sep 18, 2018 1:11 pm

zonker wrote: ↑

Tue Sep 18, 2018 11:10 am

here's some talk about this-

viewtopic/t172988/AHI-3-vs-AHI-4.html

not sure if it's helpful.

And this is why it's a good thing for (especially new) people to read all the new topics on the board... this was just gone over *last week*.

completely missed this one. I normally lurk here each day catching up on new subjects but clearly I've missed this one.

Watch for the red blocks on the left of each subject, those indicate posts you haven't read, and clicking on the red block takes you to the unread post.

Arlene1963 wrote: ↑

Tue Sep 18, 2018 12:03 pm

I came across this a while back and am still surprised by how utterly "unregulated" this field still is in some respects.
It would be like saying that you have different ways of determining if someone has hypertension. > 140/90 or >130/85, for example. Doctor gets to choose. Would any of us consider this good medicine?

Yet, in the world of sleep medicine this is how it has worked since around 2012 when the AASM rules for scoring for hypopneas changed.

https://aasm.org/aasm-clarifies-hypopne ... -criteria/

Two definitions can be used for scoring an hypopnea, and depending on which one is used you can be diagnosed with no OSA or moderate to severe OSA depending on the lab's scoring practices.

I read one example here about a year ago of someone who had an AHI of less than 5 when their PSG was scored using the 4% desat for hypopneas as per Medicare rules, and yet when scored under the 3% criteria this person's AHI was moderate at 18 events per hour. So, who decides if this person gets an XPAP prescription or not?

Go figure. It really is crazy.

Something is just not right. This needs much more scrutiny.

I get where you are coming from. But the issue is the insurance industry more so than anything else, I think. The sleep industry has already chosen, but not all the payers will go along. So it isn't really the doctor who chooses; the person's insurance has already made the decision for him.

Most medical testing is less precise and definitive that we'd like to think, anyway. There is a gray area between "at this result the person's treatment will be paid for" and "at this point the person SHOULD be treated." That gray area is valuable for giving patients and docs some wiggle room for exceptions and common sense, as customized to other factors. The problem is when we as patients insist on being treated when we've crossed the line into CAN be treated but way before SHOULD be treated, even when the treatment may not be best for us. Of course, the other issue is the docs who insist on treating everyone the same, as well. There is nothing magic about the 5 AHI line other than it being the line in the sand at which insurance agrees to let someone try PAP. That doesn't mean medically that someone with a 4 AHI wouldn't benefit from treatment OR that everyone with a 6 AHI should be put on CPAP.

The AASM recommendation has it right. Insurance needs to cave on this. In my opinion. And I've got a bunch of 'em.

JNK, here are two articles I found a while back when I was getting myself into a twist about this topic. I hope you'll read them if you have time, and possibly comment?

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

Editorial on study linked to above:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667388/

I think there is a strong case to be made that yes indeed we need to get beyond the formal categories of AHI levels to decide when to treat SDB/OSA.

But unfortunately that is so often all we as patients are presented with by rushed, overburdened sleep docs when going for an initial consultation. They don't have time and we don't have enough info.

I was never told if the result of my diagnostic PSG sleep report was based on 3% or 4%, and since all my events that night except for two central apneas were hypopneas I feel this is important information that I should have been given in my sleep study.

Arlene1963 wrote: ↑

Tue Sep 18, 2018 2:31 pm

JNK, here are two articles I found a while back when I was getting myself into a twist about this topic. I hope you'll read them if you have time, and possibly comment?

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

Editorial on study linked to above:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4667388/

I think there is a strong case to be made that yes indeed we need to get beyond the formal categories of AHI levels to decide when to treat SDB/OSA.

But unfortunately that is so often all we as patients are presented with by rushed, overburdened sleep docs when going for an initial consultation. They don't have time and we don't have enough info.

What is the future of sleep medicine beyond AHI?

My comment is that the AASM has it's recommendation but has to allow for clinics to adapt to insurance-based definitions. Their recommendation has been clear from the beginning.