Gastric bypass surgery leads to more weight loss, complications, study finds

For the first time, researchers have compared the efficacy and outcomes of two of the most common weight loss surgeries to help bariatric surgery patients make the best decision for their health and weight loss goals.

In a new study published in JAMA Surgery, researchers analyzed the weight loss and complications for laproscopic Roux-en-Y gastric bypass (RYGB) with adjustable gastric banding (AGB), and found that gastric bypass surgery resulted in greater weight loss, but more complications.

Previous studies looked at gastric bypass or gastric banding surgeries individually, making it hard to know whether the patients were comparable to make head-to-head comparisons, researcher Dr. David Arterburn, of the Group Health Research Institute, Seattle, told

“Our study adds to the confidence that doctors can talk to patients about these procedures,”  he said. “It more likely reflects the real-world experience of most patients getting this procedure in the U.S.”

According to the American Society for Metabolic and Bariatric Surgery, an estimated 179,000 bariatric surgery procedures were performed in 2013. Gastric bypass surgery accounts for 47 percent of bariatric procedures worldwide, while adjustable gastric banding accounts for 18 percent. The Centers for Disease Control and Prevention (CDC) estimates 78.6 million Americans— 34.9 percent of the population— are obese.

The new research included 7,457 patients from 10 different health systems across the country, with doctors practicing in a range of settings. The patients underwent surgery from 2005 to 2009. In 2010, researchers followed up, examining Body Mass Index (BMI) change and the 30-day rate of major adverse outcomes, as well as subsequent hospitalization and intervention.

With their findings, researchers used propensity matching, a statistical approach, to account for patient differences. While the study was not a randomized trial, the statistics allowed them to create the most balanced comparison they could, accounting for measurable statistics such as weight, age, racial and ethnic diversity.

Researchers found that patients who underwent gastric bypass had an average maximum BMI loss of 14.8, while those who had a lap band lost 8 points— nearly half the weight loss. For a patient who lost 14.8 BMI points, they would drop from the “obese” range into the “overweight” category. AGB patients would still be considered obese, but healthier because of overall weight loss. The overall study patient BMI was 44.

Bariatric surgery patients fall in two groups, depending on their BMI: Those with a BMI of 35 or more have weight-related health conditions and those with a BMI of 40 or more, regardless of complications.

On average, a bariatric surgery patient has a BMI of 47. Patients with a 40 BMI are about 100 pounds overweight.

Arterburn noted that although the band procedure is technically reversible, it still requires another major operation.

“These are generally not things you go back and redo without significant consequences,” he said.

The main complication researchers found were blood clots in the legs and lungs that occurred within the first 30 days after surgery. Bypass patients had a 3 percent chance, compared to banding patients who had a 1.3 percent chance. Other short-term complications within the study period included not being discharged from the hospital, having to repeat the procedure and death. One gastric bypass study patient died in the first 30 days; none of the banding patients died.

According to Arterburn, the study serves to show that there are clear trade-offs between the two procedures and that patients should be educated and work with their doctor to make the best decision for them.

“There’s not a clear balance sheet where one’s the winner-  but that’s the way it often is in medicine,” he said.

For a patient considering bariatric surgery, the first step is to know if you’re eligible based on BMI and health complications, Arterburn said. Understanding what the surgery means— including its risks and benefits— can allow a patient to talk to their doctor to customize their decision for what’s right for them.

“This should be about sharing this kind of information with the patient so they’re well informed about the different procedures so they can make their own personal appraisal about what’s important to them,” he said. “It really shouldn’t be about the surgeon recommending a particular procedure for a given patient as the only thing driving these decisions. Patients need to be well-informed so they can make the choice.”