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Tuesday, April 1, 2008

Does Obesity Surgery Convert "Bingers" to "Grazers"?

Classical Binge Eating Disorder (as defined by DSM-IV) is found in around 20-40% of severely obese patients presenting at bariatric centres (including ours). Numerous studies have shown that patients with BED can achieve significant weight loss, resolution of comorbidities and improvement in quality of life with obesity surgery and therefore should not generally be denied surgery.

Nevertheless, many centres (including ours) are reluctant to operate on patients with active BED fearing poorer outcomes and greater distress. It turns out that we really don't know much about how bariatric surgery affects eating patterns in patients with BED.

This question was now addressed by Susan Colles and colleagues from Monash University in Melbourne in a study published in the March issue of OBESITY. Colles and colleagues planned to study eating behaviours in 180 patients before and 12 months following laparoscopic adjustable gastric banding (LABG). Of these, 6 did not receive surgery, 1 died of a myocardial infarct and 44 (25% of eligible subjects) did not return for the 12-month survey (more on this later).

While only 14% of patients had BED at baseline, 31% were described as "uncontrolled eaters", 40% had night eating syndrome (NES) and 26% were "grazers".

Although all groups, including the "bingers" lost similar amounts of weight and BED reduced to 3% in this group, patients with preoperative BED were most likely to develop uncontrolled eating or grazing. Patients who reported uncontrolled eating or grazing after surgery tended to lose less weight and reported greater psychological distress.

Interestingly, the authors report that the 12-month non-responders were more likely to have had presurgical BED, have lost less weight and attended less clinic appointments. This may be due to patients with these behaviours feeling more ashamed about their "loss of control" and therefore avoiding follow-up visits.

This study highlights the risk of preoperative "bingers" to become "uncontrolled eaters" or "grazers" resulting in psychological distress and poorer weight outcomes. As these patients are more likely to drop out of follow-up they may also be at increased long-term risk of nutritional deficiencies and other long-term complications of bariatric surgery.

In an accompanying paper in the same issue of OBESITY, Colles and colleagues describe how "loss of control" may be at the root of the significant psychological distress of patients with BED resulting in their greater likelihood of seeking out bariatric surgery as a means to control their eating behaviour. This may well in part explain the high prevalence of BED in patients presenting in bariatric clinics.

Clearly, we need to learn more about how to pre-screen patients for potentially poor outcomes and how best to monitor post-surgical patients for the development of aberrant eating behaviours.

Given that BED, once diagnosed, is actually quite responsive to psychological treatments resulting in a remarkably high rate of resolution, I wonder about the rational for operating on patients with active BED - after all weight loss should not be the only parameter by which results of obesity surgery are measured.

Edmonton, Alberta

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