Patients Undergoing Bariatric Surgery Still Show Significant Weight Loss After 3 Years

Severely obese patients who undergo bariatric surgery still have substantial weight loss 3 years after surgery, according to findings from a recent observational cohort study. Results from the second-phase of The Longitudinal Assessment of Bariatric Surgery (LABS) Consortium were recently published online in Journal of the American Medical Association (DOI:10.1001/jama.2013.280928).

Bariatric surgery can be an option for severely obese patients, but to date few, large, long-term studies have been conducted to explore the impact surgery has on overall weight loss and other health outcomes.

Researchers in the second phase of the trial, LABS-2, took a deeper look into clinical outcomes by studying patients 3 years after undergoing either Roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric band (LAGB) at 6 geographically diverse clinical centers.

"This is the first diverse, large, carefully-studied group of people undergoing bariatric surgery in the United States that have been studied [in] this way," said Anita P. Courcoulas, MD, MPH, a lead researcher in the study.

Dr. Courcoulas and her team examined the percentage in weight change over the 3-year study period, as well as the number of diabetic participants who achieved glycated hemoglobin levels <6.5% or a fasting plasma glucose value <126 mg/dL, without drug therapy. The researchers also assessed lipid and hypertension outcomes.

Participants in the LABS-2 observational study were ≥18 years of age and had undergone first-time bariatric surgical procedures between 2006 and 2009. Follow-up continued through September 2012 with participants taking part in assessments prior to surgery and at the 6- and 12-month mark before moving to annual assessments.

At baseline, 2458 participants had a median body mass index of 45.9 kg/m², with an interquartile ratio (IQR) of 41.7% to 51.5%. In this analysis, researchers included only the results of patients who had undergone RYGB (n=1738) and LAGB procedures (n=610).

Dr. Courcoulas said the primary outcome of the study was weight loss as well as improvement in diabetes, lipids, and blood pressure.

After a follow-up period of 3 years, researchers found that patients who had undergone RYGB or LAGB still showed significant weight loss, although most of the weight change occurred in the first year after surgery. For instance, patients who had undergone RYGB had a 31.5% decrease in their baseline body weight (IQR, 24.6%-38.4%; range, 59.2% loss to 0.9% gain) at the 3-year mark, while patients who had undergone LAGB had a 15.9% decrease in weight (IQR, 7.9%-23%; range, 56.1% loss to 12.6% gain) at 3 years.

The change in weight varied between patients, according to researchers who were able to identify 5 distinct weight loss trajectory groups for each procedure.

"We really show very clearly and very carefully that there is a lot of variability in the response to surgery when it comes to weight loss. So, by that I mean [that] an individual undergoes a certain operation, [and] it is hard to predict exactly the result," Dr. Courcoulas said.

When researchers looked at other health outcomes, such as diabetes, they also found improvements. Of the participants who had diabetes at the time of surgery, 67.5% who had RYGB and 28.6% who had LABG were in at least partial diabetes remission after 3 years. In addition, 61.9% of the RYGB group and 27.1% of the LAGB group who had dyslipidemia at the study's baseline were in remission after 3 years. The researchers also observed changes to patients who had presented at baseline with hypertension and reported that at the 3-year mark, 38.2% in the RYGB group and 17.4% in the LAGB group were in remission.

The researchers concluded that, overall, there was variability in the amount of weight loss and the effect each of the procedures had on other health outcomes. Dr. Courcoulas said more research that focuses on longer follow-up times and identifies factors that can help certain individuals continue weight loss after surgery is still needed.