PITTSBURGH — Three years after more than 2000 severely obese men and women underwent Roux-en-Y gastric bypass or laparoscopic adjustable gastric banding, overall weight loss was substantial and sustained, researchers report.

However, not all patients respond the same way: the study identified very different weight-loss trajectories, as well as varied improvements in hypertension, diabetes, and dyslipidemia and in rates of mortality and reoperation.

The 3-year outcomes from the Longitudinal Assessment of Bariatric Surgery (LABS) study were published online in the Journal of the American Medical Association on November 4, 2013 and will be presented at Obesity Week 2013: The American Society for Metabolic and Bariatric Surgery and the Obesity Society Joint Annual Scientific Meeting, held November 11 through 16 in Atlanta, Georgia.

"I think one of the most important findings is we really demonstrate that there is a lot of variability in response to treatment," lead author Anita Courcoulas, MD, from the University of Pittsburgh Medical Center, Pennsylvania, told Medscape Medical News.

This suggests that there is opportunity to "improve patient selection and education prior to surgery as well as enhance support for continued adherence to lifestyle adjustments in the postoperative years," she and her colleagues write.

A First Look at Medium-term Outcomes With Contemporary Surgery

Dr. Courcoulas and colleagues explain that although bariatric surgery is generally accepted as the most effective means for inducing weight loss in very overweight patients, few studies exist reporting outcomes longer than 2 years after the surgery was performed.

Long-term outcome studies that do exist are mostly case series, are from limited geographical areas, or report surgical procedures no longer performed. For example, high-quality, long-term outcomes from the Swedish Obese Subjects (SOS) study are well described, but most of the participants underwent a vertical banded gastroplasty procedure, an operation no longer used. And 6-year follow-up after gastric bypass has been reported, they note, but the data may not be generalizable because all the participants were from 1 surgical practice in Utah.

LABS enrolled severely obese participants older than 18 years who underwent bariatric surgery at 1 of 10 hospitals at 6 geographically diverse locations in the United States between March 2006 and April 2009. The 30-day safety outcomes were determined in the first phase, LABS-1; LABS-2 looked at 3-year outcomes.

The current study specifically looked at the following 3-year outcomes: weight change from baseline, comorbid conditions, and deaths and reoperations. The researchers analyzed data from 1738 participants who underwent Roux-en-Y gastric bypass (referred to as gastric bypass) and 610 participants who underwent laparoscopic adjustable gastric banding (gastric banding), but they did not include participants who underwent less common procedures — sleeve gastrectomy (59 participants), biliopancreatic diversion with duodenal switch (19), or banded gastric bypass with a nonadjustable band (32).

The median age of the participants was 46 years (range, 18 to 78 years); 79% were women.

The researchers identified 5 unique patterns of weight loss and regain for each type of surgery. At 6 months, only 2.1% of patients who had undergone gastric bypass began to regain weight in comparison with 18.9% of patients who had undergone gastric banding.

At 3 years, gastric-bypass patients had lost a median of 41 kg (31.5% of initial body weight), whereas their counterparts who had undergone gastric banding had lost 20 kg (15.9% of initial body weight).

Those who had had gastric bypass were also more likely to have better cardiometabolic profiles. At 3 years, 67.5% of the gastric-bypass patients vs 28.6% of those who had gastric banding had had at least partial remission of diabetes. A similar pattern was seen for remission of dyslipidemia (61.9% and 27.1%, respectively) and remission of hypertension (38.2% and 17.4%, respectively).

More Study Needed to Spot Potential Responders, Nonresponders

However, the surgery does carry inherent risk, the researchers note. At 3 years, there were 16 deaths (0.9% of patients) in the gastric-bypass group and 5 deaths (0.8%) in the gastric-banding group. In addition, 4 patients (0.3%) in the gastric-bypass group and 77 patients (17.5%) in the gastric-banding group required a reoperation.

Dr. Courcoulas stressed that it is therefore always key to review the benefits and risks of a surgical weight-loss procedure on a case-by-case basis for each individual, potential patient.

In an accompanying editorial, Sayeed Ikramuddin, MD, from the University of Minnesota, in Minneapolis, and deputy editor of JAMA Edward Livingston, MD, from Chicago, Illinois, note that this study, along with 3 other reports from the LABS data set that were published alongside it ― including one on outcomes in teenagers ― provides "important new information about short- and medium-term outcomes of bariatric surgery, and the findings are generally encouraging."

However, the editorial also highlights that "not all patients respond optimally, and one of the next challenges for bariatric surgery is to prospectively identify patients who will likely have good outcomes from these operations, predict which patients will not do well from surgery, and find other, more effective treatments for those patients."

Self-Reported Body Weights Are Not Far Off the Mark

Meanwhile, a separate research letter published with the articles in JAMA reports that in 988 men and women who participated in LABS, the self-reported body weights were, on average, not more than 1 kg less than actual body weights that were measured by study personnel.

This suggests that self-reported body weights are accurate enough to use in research studies of bariatric surgery when more precise measures are not available, Nicholas Christian, PhD, from the University of Pittsburgh Graduate School of Public Health, and colleagues write.

Dr. Ikramuddin and Dr. Livingston agree. The closeness in values demonstrates "that it is possible to obtain reasonably accurate body-weight information from patient self-report of weights," they conclude.

LABS-2 was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Dr. Courcoulas reported having received research grants from Allergan, Pfizer, Covidien, EndoGastric Solutions, and Nutrisystem and serving on the scientific advisory board of Ethicon J & J Healthcare System. The conflict of interest disclosures of the other study authors are listed with the article. Dr. Ikramuddin reported that he serves on an advisory board for Novo Nordisk, USGI Medical, and Medica; consults for MetaModix; and receives grant support from Covidien, EnteroMedics, and ReShape Medical.

Obesity 2013: The Obesity Society Annual Meeting. Presented November 15, 2013.

JAMA. Published online November 4, 2013. Abstract, Editorial , Research Letter

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