Patients Denied Bariatric Surgery Get OSA, GERD etc

Hi All

The latest about sleep apnea from the 27th Annual Meeting of the American Society for Metabolic & Bariatric Surgery (ASMBS) is at -

http://www.medicalnewstoday.com/articles/192799.php

and a link to Bariatric Surgery is at -

http://en.wikipedia.org/wiki/Bariatric_surgery

Mars

There has been some mention on this forum of OSA causing obesity more often than obesity causes OSA. This article indicates that OSA, "an obesity-related disease", developed in the study sample who were denied bariatric surgery, and whose BMI did not change, whereas in those who had the surgery, there was a much lower rate of development of obesity-related conditions, such as apnea:

After three years, the average BMI in the surgical group had dropped to 30.5 and less than 1 percent of patients developed new obesity-related conditions, while a large number of patients in the denial group grew unhealthier. Though BMIs remained relatively unchanged in the denial group, more than 40 percent developed hypertension, 34 percent developed obstructive sleep apnea and nearly 20 percent developed gastroesophageal reflux disease (GERD).

Another study showed that in those who had the surgery and lost a significant amount of weight, sleep apnea was eliminated in more than 85%:

A 2004 study published in the Journal of the American Medical Association (JAMA) showed bariatric surgery patients lost between 62 and 75 percent of their excess weight and resolved or improved a number of obesity-related conditions including Type 2 diabetes (remission in 76.8% and significant improvement in 86%); hypertension (eliminated in 61.7% and significantly improvement in 78.5%); high cholesterol (reduced in more than 70%); and sleep apnea (eliminated in more than 85%).

Obviously there are those who are not overweight and who have apnea, and there are those who have other risk factors for apnea and might have developed it even in the absence of the weight gain. And of course, having OSA makes it harder to lose weight. Still, through my drug-induced haze, this seems pretty compelling evidence that obesity --> OSA and weight loss --> elimination of OSA in an impressive majority of obese individuals studied.

SleepingUgly wrote:
Another study showed that in those who had the surgery and lost a significant amount of weight, sleep apnea was eliminated in more than 85%:

Still, through my drug-induced haze, this seems pretty compelling evidence that obesity --> OSA and weight loss --> elimination of OSA in an impressive majority of obese individuals studied.

The problem I have with that is that many people think the reverse is automatically true. All these studies keep harping on obesity being the cause and weight loss the solution when it is only true for a certain percentage of people. It means that us thinner people don't get tested until we just about croak. I am tired of being a foot note.

SleepingUgly wrote: Still, through my drug-induced haze, this seems pretty compelling evidence that obesity --> OSA and weight loss --> elimination of OSA in an impressive majority of obese individuals studied.

I agree... According to that study, there is a strong correlation between: A) weight loss and B) apnea loss among bariatric surgery candidates.

I suppose one question is whether that same correlation between A and B statistically holds strong as we move down the OSA population's BMI scale----away from bariatric surgery candidates. While the epidemiology discussed on this page, citing Nieto et al, doesn't neatly answer that question... it at least attempts to shed more light on the relationship between AHI and BMI:
http://www.sleepapnea.org/resources/pubs/bmi.html

Nice pie charts too!

-SWS wrote: http://www.sleepapnea.org/resources/pubs/bmi.html

Nice pie charts too!

The pie charts show the vast majority of those with apnea are overweight or obese.

SleepingUgly wrote:

-SWS wrote: http://www.sleepapnea.org/resources/pubs/bmi.html

Nice pie charts too!

The pie charts show the vast majority of those with apnea are overweight or obese.

There are three OSA subpopulations on that pie chart. While apnea's obesity causation rate is 85% in the obese subpopulation (statistic cited above), obesity as a pathogenic cause clearly cannot be extended onto the normal-weight subpopulation. Excessive weight as a causal/non-causal factor is thus more clearly defined among those two extreme OSA subpopulations of the three...

Enter the gray-zone subpopulation... the overweight OSA patients caught in the middle. Just as soon as we acknowledge that there are multiple pathogenic/causal reasons for apnea, then we risk methodological "selection bias" problems by extending the obese subpopulation's 85% causation rate onto the other subpopulations. Regarding those overweight OSA patients caught in that middle-zone of the apnea-causation puzzle:

1) How many are overweight because of their apnea, and
2) How many have apnea precisely because they are overweight (versus those clearly delineated ones in the obese and normal-weight subpopulations)?

Anecdotally, very few in that middle-weight subpopulation have ever been able to make the apnea-remission claim, due to weight loss, on the message boards over the years. And, unfortunately, I have yet to see hard statistics citing that significant numbers of OSA patients in that middle-weight OSA subpopulation can cure their apnea with weight loss alone. Not to detract from the hard fact that losing weight can save lives for an entire variety of health reasons.

-SWS wrote: Anecdotally, very few in that middle-weight subpopulation have ever been able to make the apnea-remission claim, due to weight loss, on the message boards over the years. And, unfortunately, I have yet to see hard statistics citing that significant numbers of OSA patients in that middle-weight OSA subpopulation can cure their apnea with weight loss alone. Not to detract from the hard fact that losing weight can save lives for an entire variety of health reasons.

There must be some articles on the topic of weight loss as a treatment for apnea. I'm sure I've seen it embedded in other articles. As far as anecdotal reports from a cpap forum population, that will select for people who fail to get off cpap by weight loss alone, or they wouldn't be here. But in general, I know of few people who are overweight, lose their excess weight, and maintain that lower weight for a substantial period of time.

SleepingUgly wrote:There must be some articles on the topic of weight loss as a treatment for apnea.

Of course IMO... We can see above that for 85% of the obese population that weight loss is an excellent treatment for apnea remission (thanks for those statistics). And I also think it's considered adjunct treatment for that overweight "gray zone" OSA subpopulation because it will lessen apnea's severity more often than not (but myriad non-apnea health benefits as well). I don't think weight loss alone tends to achieve complete apnea remission in that latter OSA subpopulation, though.

SleepingUgly wrote:As far as anecdotal reports from a cpap forum population, that will select for people who fail to get off cpap by weight loss alone, or they wouldn't be here.

That's probably true to some extent.... However, over the years I believe we have heard from far more successful dental appliance cross-over patients than we have heard from total-remission weight loss patients. I suspect we should have heard at least as much from the successful weight loss patients as we did from the successful dental cross-over patients (with their comparatively low success rates).

Well, let's do a study here. Those who are overweight can lose weight, track AHI, pressures, and repeat a sleep study once BMI is in the "normal" range. Who would like to enroll?

BTW, I hope it's clear that I am not saying weight is the only factor in OSA. Menopause, for example, is almost guaranteed to worsen OSA (and it causes weight gain). Obviously there are other variables that interact to cause OSA. However, to suggest that weight is not a leading cause of OSA in the vast majority of people seems absurd to me. And that's cause for celebration, isn't it? After all, of all the variables, it's the only one that is under our control.

(Before everyone attacks, please remember that I have stitches in my nose and throat, so don't pummel me too hard...)

SleepingUgly wrote:BTW, I hope it's clear that I am not saying weight is the only factor in OSA. Menopause, for example, is almost guaranteed to worsen OSA (and it causes weight gain). Obviously there are other variables that interact to cause OSA. However, to suggest that weight is not a leading cause of OSA in the vast majority of people seems absurd to me. And that's cause for celebration, isn't it? After all, of all the variables, it's the only one that is under our control.

(Before everyone attacks, please remember that I have stitches in my nose and throat, so don't pummel me too hard...)

Awww, no one is going to mess with my Uggy.

All of the people I know in real life with OSA are normal weights, except for me. But I am still not going to pummel you.

http://www.ncbi.nlm.nih.gov/pubmed/15852048

http://www.ncbi.nlm.nih.gov/pubmed/7963174

http://www.ncbi.nlm.nih.gov/pubmed/15479938

http://www.ncbi.nlm.nih.gov/pubmed/20202954

http://www.ncbi.nlm.nih.gov/pubmed/19786682

http://www.ncbi.nlm.nih.gov/pubmed/19486716

http://www.ncbi.nlm.nih.gov/pubmed/18763424

Your data and studies above all speak of an obese OSA subpopulation---one of three slices on that pie chart. In my own posts above, I clearly agree about that 38.1% obese slice of the pie chart.

SleepingUgly wrote: However, to suggest that weight is not a leading cause of OSA in the vast majority of people seems absurd to me.

Well, lend some clarification, please. When you say "leading cause of OSA in the vast majority of people" are you adding together cases of: 1) weight as a single cause, along with: 2) weight as a contributing cause (thus weight often also contributing to multifactorial pathogenesis)? If THAT'S what you're saying above, then I agree with you. And in either of those two cases weight loss is clearly beneficial---although not always curative.

Conversely, if you're saying weight acts as a sole leading cause across the majority of the entire OSA population----and not just the BMI >30 subpopulation----then I have to say I honestly don't see data anywhere in this thread supporting that conclusion.

SleepingUgly wrote:(Before everyone attacks, please remember that I have stitches in my nose and throat, so don't pummel me too hard...)

I think you deserve an award as champion for your posts and sentiment in this thread only four days out of surgery! Thanks for your views.

Aaaargh! Where is the post I was in the middle of drafting?! I'll try again...

-SWS wrote:When you say "leading cause of OSA in the vast majority of people" are you adding together cases of: 1) weight as a single cause, along with: 2) weight as a contributing cause (thus weight often also contributing to multifactorial pathogenesis)?

I'm saying that in some people, weight likely has a nearly direct/causal relationship, and in some, it moderates the relationship between other risk factors and OSA (i.e., weight interacts with other variables to cause OSA). The reality is that there are very few variables in the real world that act in isolation to CAUSE other variables. So I would agree that it is nearly always multifactorial. In some overweight people, eliminating the excess weight will "cure" the OSA, and in some it will only improve it (and of course, in some it will be unchanged). Also, keep in mind that BMI is highly correlated with oxygen desaturations. So a person could have an RDI of 30 with significant oxygen saturations or an RDI of 30 without significant desats. IMO, the latter is an improvement over the former.

Conversely, if you're saying weight acts as a sole leading cause across the majority of the entire OSA population----and not just the BMI >30 subpopulation----then I have to say I honestly don't see data anywhere in this thread supporting that conclusion.

Also, remember that BMI > 30 and <30 are artificial categorizations of a continuous variable. There is no meaningful difference between a BMI of 29 and one of 31.

Again, there are few "sole" causes. Perhaps for those with a higher BMI, weight plays a more direct role (but my guess is still through indirect mechanisms) in OSA, whereas for those with a lower BMI who are still "overweight", the relationship is more interactive.

Oh, here is an excellent powerpoint presentation on this topic by a reliable source:

http://www.stanford.edu/~davesv/Weight%20&%20OSA.ppt

SleepingUgly wrote: Also, remember that BMI > 30 and <30 are artificial categorizations of a continuous variable.

Right. For instance, in the BMI > 30 group discussed earlier (the obese group), apnea-loss occurred in some weight-loss patients @ a point higher than that BMI=30 threshold.

SleepingUgly wrote: There is no meaningful difference between a BMI of 29 and one of 31.

That reminds me of the metaphor about deciding exactly where to draw the line between day and night: there are really no meaningful differences about where to draw the lines within the shadowy dusk or shadowy dawn regions; and yet the resultant groups are as measurably different as day and night.

SleepingUgly wrote: Oh, here is an excellent powerpoint presentation on this topic by a reliable source:

http://www.stanford.edu/~davesv/Weight%20&%20OSA.ppt

Thanks. That IS an excellent presentation---one citing many relevant studies. The Lam 2007 study cited showed 8 of 34 overweight (non-obese) patients managed to achieve an AHI < 5 with weight loss. That's far better than I thought entering this thread. Many thanks to SleepingUgly and Mars for an enlightening and even empirical thread about weight loss relative to OSA.

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This is a touchy but VERY important question for the forum IMHO: do weight-loss discussions receive due time or short consideration on the OSA message boards?

We might even need to soul search about that one a bit... I hope the honest answer is that weight-loss discussions DO receive their fair share of discussion time around here. Otherwise, I fear we are at risk of slowly killing our readership (each other) with emotional kindness...