Wednesday, May 18, 2011

Does Preoperative Weight Loss Affect Short-Term Postoperative Weight Loss?

Mental Health Blog Party Badge

May is "Mental Health Month" and today is "Mental Health Month Blog Party," an initiative of the American Psychological Association's Public Education Campaign. Today, bloggers who write about mental health issues will be linked to on APA's public information web site:

So, since every bariatric surgery patient is indoctrinated with the message, "Bariatric surgery is a tool, not a panacea, and I know I have to make lifestyle changes to maintain my weight loss," I thought I would blog today about the value - or lack thereof - of losing weight before having surgery. Some bariatric surgery programs encourage, or even require, prospective patients to lose some amount of weight before having their procedure.

After all, doesn't it make good intuitive sense that solidifying some of those important behavioral changes would lead to a better outcome? Researchers at the Stanford School of Medicine asked that question and reported their results in today's article.
Eisenberg, D., Duffy, A., & Bell, R. (2010). Does Preoperative Weight Change Predict Postoperative Weight Loss after Laparoscopic Roux-en-Y Gastric Bypass in the Short Term? Journal of Obesity, 2010, 1-4 DOI: 10.1155/2010/907097

The authors question two basic assumptions in bariatric surgery research and practice - that preoperative weight loss indicates an individual's intrinsic motivation for behavior modification, and that intrinsic motivation is a valid predictor of outcome. Some institutions may deny patients bariatric surgery when those patients do not demonstrate sufficient commitment by losing weight on their own.

The researchers deserve credit for designing a very well-controlled study: all 354 study participants had laparoscopic Roux-en-Y gastric bypass surgery by the same surgeon at a single institution. All preoperative and postoperative care followed the same guidelines. Large surgical centers tend to have dedicated well-trained staff and large patient volumes. They lend themselves to this type of large prospective study.

Of the 354 patients having surgery, 256 were available for evaluation 1 year later and were included in the study. Of these patients, 125 lost weight before surgery, 104 gained weight, and 27 had no change. A statistical analysis did not find a significant correlation between weight lost (or gained) before surgery and weight lost in the first year.

Thus, the authors conclude (correctly, given their assumptions and research question) that preoperative weight loss should not be required prior to Roux-en-Y because preoperative weight change does not affect 1-year outcomes . . . assuming 1-year outcomes are all one is interested in.

But what about longer-term outcomes? It is pretty much a given that the first year post-op will result in significant weight loss. That's not where the problems set in. Continuing to lose weight and maintaining that weight loss after the first 12-24 months is where the challenges lie. And research tells us that long term success requires long-term behavior changes.

So the next question is . . . Does preoperative behavior change affect behavior change and weight loss in the long term, say 3-5 years? In other words, does the intuitive assumption that the sooner one starts behavior change the longer and stronger those new habits are likely to remain? Stay tuned.

And Happy Mental Health Month!