Thursday, August 23, 2007

Do gastric bypass patients really live longer than fat people?

In the last couple of days, the headliner news has been that two studies have suggested that gastric bypass patients live longer than fat people.

"Weight loss surgery patients are SIGNIFICANTLY LESS likely to die prematurely" stated an article in the Washington Post.
"This is HUGE!", commented Dr David Flum, to the Washington Post. Dr Flum is a bariatric surgeon.
"It's going to dispel the notion that bariatric surgery is cosmetic surgery and support the notion that it saves lives," boasted Dr. Philip Schauer, another weight loss surgery surgeon who has been prominent in the news articles denying the negative repercussions of bariatric surgery.
"The question as to whether intentional weight loss improves life span has been answered," wrote George Bray, a known enthusiastic advocate of the diet industry.

All well and good but do the two studies they quoted really prove their point?

The answer is no.

In the Swedish Obesity Study (reported in NEJ Dec 23, 2004, vol 351, no. 126) , although 11,000 people applied to be included, only 3900 were accepted to receive weight loss surgery in 1987 when the study was initiated. A matched equal number of controls were selected and given diet advice. The cohort was examined at the 2 year point in the study and at the 10 year point.

At the 2 year point (2 years post op for the weight loss surgery patients), a goodly portion had been "lost to follow up" and only 2010 patients (out of the original 3900) were examined. It's likely that most of these were gastric banding because that was the more often done procedure in the 1980's. Two years is obviously NOT long term follow up.

At the 10 year point, only 627 of the original 3900 were left to examine - the rest had been "lost to followup". And of these 627, only 34 were gastric bypass patients. Of the rest, 400 some were vertical gastric banding and the remainder were adjustable banding.

Since only 16 percent of the weight loss surgery patients were available to examine at the 10 year point, this study poses more questions than answers including the usual question "where are the others?"

Well, we got sort of an answer on this one. Apparently, the 85 percent could be tracked as far as whether they died because of Sweden's nationalized health care records. But that they were "lost for follow up" suggests that their results were even less impressive than the 641 they COULD follow up - i.e. those folks available for follow up had only kept off an average of 16 percent of their weight!

So lets talk about the deaths. A fine analysis by a medical expert solves the mystery. The fat people had a 1.3 percent greater death rate which works out to 100 and some more deaths in the 3900 fat people than in the WLS patients. BUT, apparently, according to the researchers on the the Swedish Obesity study, they did not randomize the study which means instead of taking a random section of fat people, they could pick and choose. And pick and choose they did. Turns out the fat people chosen for this study had 25 percent MORE heart disease, 6.3 percent more diabetes than did those chosen to receive WLS and also the fat folks were an average of 1.5 years older than those who got WLS.

So the S.O.S. if properly interpreted, suggests the opposite of what the news told us... that fat people live significantly longer than WLS patients (and keep in mind most of the cohort in the S.O.S. were gastric banding which has a much lower death rate than gastric bypass). Why? Because there was 25 percent MORE heart disease in the fat people but only a 1.3 greater incidence of death! (To be even with the WLS patients, the fat people should have had a 25 percent greater incidence of death). That causes a hmmm, doesn't it? For details of the analysis please visit here (it's a great blog and you might want to read all the posts!).

The second study took place in Utah. Here 7925 gastric bypass patients were compared to 7925 fat people. The fat people were selected by weight recorded on their driver's licenses.

Researchers found that there were 108 more deaths in the fat people than in the gastric bypass patients (231 deaths in the fat controls, 113 deaths in the gastric bypass patients).

This study seems to have all kinds of problems in my book. First of all, who puts their real weight on their driver's license? Secondly there seems to have been no contact with any kind of medical records on the fat people... the deaths were taken from the death certificates on file. So we have no idea whether the fat people chosen to be the controls were smokers (greatly increases their risk) or yo yo dieters which greatly increases the death risk. We also have no idea of whether they exercised or not which greatly DECREASES the risk of death in people of all sizes. (REF: Lee CD, Blair SN, Jackson AS. Cardiorespiratory fitness, body composition, and all-cause and cardiovascular disease mortality in men. American Journal of Clinical Nutrition. 1999 Mar;69(3):373-80)

Secondly with regards to the gastric bypass patients, the followup was only 7 years and the serious repercussions of vitamin deficiencies and nutrient shortages in gastric bypass tend to show up after the 10th year post op. Basically this was NOT a long term study.

So these two studies don't prove ANYTHING about longevity after gastric bypass.

And also, the end weight results of both studies were a bit disappointing to some gastric bypass patients. At the 10 year point patients had only retained an average of a 50 - 60 lb weight loss (for those 350 lbs to start with and up). And only 35 percent of patients were still "diabetes free" so the weight loss surgery didn't work really well for diabetes either, it seems.

Meanwhile the ASBS, the professional organization for bariatric surgeons, has renamed themselves to include "metabolic diseases" in anticipation of greatly increasing their client base to normal weight diabetics.

I guess since Edward Mason, the inventor of the gastric bypass, left their presidency, they might have forgotten that the reason he thought a "billroth II" (predecessor of today's gastric bypass) would work for fat people was because normal weight patients after a billroth II could not keep their weight at anything close to normal!

Also the expected lifespan (for normal weight patients) after a Billroth II was 15 to 25 years. Since modern medication and treatment there is no expected shortening of lifespan for type II diabetics.

As far as the news media's exaggeration of these NON findings from the two studies, a quote by Stephen Milloy comes to mind:

"But who needs data when you can spoon-feed junk science to a gullible media?"
- Steven Milloy, Fox News

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