Pharmacotherapy as Adjunct Treatment After Bariatric Surgery

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Obesity medicine physicians in the Massachusetts General Hospital Weight Center use the latest scientific research to provide cutting-edge care to pediatric and adult patients who have undergone weight loss surgery without satisfactory results. Typically, 25%–35% of people with obesity who undergo bariatric surgery experience weight regain or inadequate weight loss within two to five years of the procedure.

"If someone carries 100 pounds of excess weight, at their lowest weight after surgery they'll typically have lost 50% to 60% of that," says Fatima Cody Stanford, MD, MPH, MPA, an obesity medicine physician-scientist at Mass General. "While that is a good start, it still doesn't put them in a 'healthy weight' category. We need to do more for these patients and for those who regain the weight they lost after surgery."

Dr. Stanford and her colleagues at the Weight Center have extensively studied the use of pharmacotherapy agents as an adjunct for managing inadequate weight loss or weight regain after bariatric surgery.

Efficacy of Weight Loss Medications After Bariatric Surgery

Following sleeve gastrectomy or Roux-en-Y gastric bypass surgery, many patients continue to struggle with obesity even after optimizing lifestyle factors such as physical activity, sleep and diet. Revision surgery can be risky and doesn't result in increased weight loss unless it is performed to correct anatomical issues or surgery-related concerns such as leaks from staple line breakdown. Experts agree that additional therapies are needed to help these patients achieve and maintain weight loss after bariatric surgery.

To study whether weight-loss medications might be effective, Dr. Stanford and colleagues performed a large retrospective study of the effect of these drugs in this population, the results of which were published in Surgery for Obesity and Related Diseases.

Of the 319 patients examined:

• 54% (172 patients) lost more than 5% of their total weight when taking medications after surgery
• 30% (96 patients) lost more than 10% of their total weight
• 15% (49 patients) lost more than 15% of their total weight

When the investigators broke down these results by age group—patients over age 60 and patients age 21 to 30—the findings were similar: Pharmacotherapy is an effective adjunct therapy following surgery.

Medication Effectiveness Differs by Age Group

The study explored 15 on- and off-label medications used for the treatment of obesity. From this limited group of drugs, topiramate emerged as the most effective single-agent medication in the postoperative setting: Bariatric surgery patients were twice as likely to lose 5% or more of their total body weight when on it.

Dr. Stanford went on to conduct retrospective studies of different age groups to determine which medicines were most effective. For patients age 21 to 30, phentermine rose to the top, but for patients over age 60, liraglutide was found to be most helpful.

While the data suggest weight-loss medications are effective after bariatric surgery, providers may be hesitant to use them following the withdrawal of several obesity drugs from the market because they caused side effects including heart valve issues.

"I understand the hesitation," says Dr. Stanford. "Safety is paramount since the use of weight loss medications after bariatric surgery is likely lifelong. But a lot of the medications we now use are very safe and have years of data behind them."

Surgery and Pharmacotherapy in Tandem to Control Obesity

Many people incorrectly presume that surgically reducing the size of the stomach should be all it takes to spur initial weight loss and halt weight regain, but Dr. Stanford says that's not entirely correct. "There are a lot of things we're learning. It's not just the mechanics. A lot is going on between the brain and the gut and how that affects hunger and satiety," says Dr. Stanford. "Postsurgery, we see improvement in certain hormonal signals that contribute to obesity."

One of those signals comes from ghrelin, a key hunger-promoting hormone produced primarily in the fundus of the stomach. When a significant portion of the fundus is removed, hunger signaling is often reduced.

Weight loss surgery also appears to improve the signaling of glucagon-like peptide-1 (GLP-1) agonist. GLP-1 stimulates insulin secretion, inhibits the distribution of glucagon, delays gastric emptying and promotes satiety.

Adding medication to surgery creates a second line of defense for weight control. The mechanics of weight loss drugs are not completely understood, but they are believed to alter the function of neurotransmitters in the brain to inhibit food cravings.

A Multimodal Approach to Obesity Treatment

Dr. Stanford relates bariatric surgery for obesity to treating refractory hypertension. Hypertensive patients may need to do several things, including modifying diet, adding on a beta-blocker or ace inhibitor and adding exercise.

"The same is true for patients who have obesity," she says. "Surgery starts the ball rolling, but we likely need to add complementary treatments like pharmacotherapy and lifestyle modifications to maximize the benefit of surgery and sustain long-term weight loss."

At the Mass General Weight Center, Dr. Stanford and her team work in tandem with surgeons and primary care providers to ensure patients have comprehensive care. They have published a resource guide for other providers who want to prescribe pharmacotherapy after bariatric surgery.

Dr. Stanford also stresses that providers need to really listen and take cues from their patients—many of whom pick up on provider biases about obesity and may ultimately leave medical care because they don't feel respected—to guide the postoperative approach.

"The key thing is we need to recognize that obesity is a disease with real pathophysiology. When we as providers can help patients address obesity, which is the root cause of so many downstream health problems, we're increasing their health and the health of society," she says. "It is heartwarming to see patients get excited when they come off of medications for hypertension or high cholesterol, knowing it's the progressive, multifaceted treatments that helped them reach a healthy baseline."

Learn more about the Mass General Weight Center

Refer a patient to the Mass General Weight Center