From this article in CNN:
http://thechart.blogs.cnn.com/2011/06/12/bariatric-surgery-doesnt-help-obese-live-longer-study-says/?hpt=hp_t2
I’m having trouble understanding what the following statement mean. THey seem to contridict each other:
It would make sense that death rates would be reduced, and the first statement implies this. But I don’t know how to make sense of the second sentence.
Two studies contradicted each other. First study shows mortality reduction, second study does not. Time for the tie breaker!
Nope, I don’t think so. I think it was just one study.
This is a vague statement - the “raw rates” (whatever that means) were compared to what?
Are they reporting that mortality reduction is not seen in a subset of older V.A. patients?
CNN has not distinguished itself here.
I just read the JAMA article quickly, but it looks like the results are different analyses – the first showed improved mortality for bariatric surgery when matched with nonsurgical patients who had similar characteristics, but when another analysis was done that attempted to match them against similar patients who were also similarly likely to have bariatric surgery, there was no benefit seen. I’ll have to read this again to see how they picked this second group. Keep in mind this is an old, heavy, and very male cohort, so these results can’t be applied to everyone.
It would not surprise me at all to hear that bariatric surgery failed to reduce mortality, or even increased it. It make make you lose excess weight, but it fucks you up in significant other ways.
That said, I also cannot make much sense of the sentenced quited in the OP.
I would never rely on a regular news outlet to understand the conclusions of a medical study. Their use of the word “similar” isn’t very helpful here. I’ll take another stab at this.
The problem is: Who do you want to compare these bariatric surgery patients to? The first analysis compared them to another group of vets in the same database matched by “age, sex, self-reported race, marital status, BMI, comorbidity burden measured by the diagnostic cost group score, and Veterans Integrated Service Network of residence.” But a cohort that is mordibly obese and chooses not to have bariatric surgery is for that reason not exactly the same as a cohort that does – maybe they’re sicker, maybe they’re healthier, maybe its cultural, maybe there are other factors that makes them not have surgery. So the second analysis attempts to pick a group of patients who were (in theory) just as likely as the surgery group to have had surgery, but didn’t. I don’t know anything about propensity analysis, so I can’t comment on how valid this is.
The JAMA conclusion says this (although I’m not sure it clears things up)
In addition, I have read that a fairly high percentage of people eventually gain their weight back (and then some) a certain number of years after receiving the surgery. Does anyone have the stats on this?
Male veterans may be - probably are - different from the general public, but bariatric surgery is heavily discouraged for people over 60. The side effects can be severe, there is a longer history of other health problems, and to maintain the weight loss a new style of healthy eating s required and that’s harder for older patients to adjust to.
Bariatric surgery is therefore something for younger obese people. And those people, even if candidates for bariatric surgery, are likely to live another six years no matter what. It’s probably just too short a time to have much meaning as a general indicator.
But it significantly reduces morbidity compared to a matched group. That’s a highly positive finding. And it should give the broader pool of candidates some real hope.
So some weight is regained but on average only a fraction of that lost.
So from the get go, yeah. This is, by design, a sicker and older population, and much of the long term damage from obesity’s effects are already done. This population is sick enough that four times as many of them do not survive the procedure, which right there biases the results some. And the follow up of a mean of six years also makes no effect not a huge shock, as the article states:
That conclusion seems valid - bariatric surgery may not decrease mortality in older sicker morbidly obese males at 6 years out. Whether or not the decrease in various morbidities (also less dramatic for this than in other studied populations) makes it worthwhile to do even without evidence of a few years out mortality benefit is an open issue.
I got bariatric surgery 6 years ago (RNY). One thing that was pounded into our heads was that we WOULD lose the weight, but that was because we would be forced to alter our lifestyles. Since we would be forced to alter those habits for at least 18 months it would be hoped that we would develop new, better habits.
We were told that, on average, 15% of the RNY patients would go back to their old ways and gain it all back again.