Bariatric surgery enters mainstream for treatment of diabetes

Growing evidence suggests that bariatric surgery, commonly known for its effectiveness in treating severe obesity, may also help in the treatment and achievement of remission of type 2 diabetes. Although study results are mostly short term and more long-term follow-up is needed, the Swedish Obese Subjects trial has follow-up data up to 20 years.

“When you look at the effect of surgery on those patients, the patients [with diabetes] who have intervention before 5 years duration [of the disease] are the ones who get the best results,” said John M. Morton, MD, MPH, FACS, director of bariatric surgery and surgical quality at Stanford University School of Medicine. “I like to think that those are patients who are more metabolically receptive to change and it’s before the pancreas and insulin receptors can burn out; [patients] still have an ability to recover.”

Endocrine Today interviewed several experts on the different types of bariatric surgery, patient indications, effectiveness for obesity and diabetes, as well as new developments.

Types of bariatric surgery

Currently, the main types of bariatric surgery being performed are gastric bypass, sleeve gastrectomy, biliopancreatic diversion with duodenal switch and adjustable gastric band procedures.

“All of these procedures limit the amount of food you can take in through restricting the stomach size,” said David Arterburn, MD, MPH, an investigator and physician at Group Health Research Institute and the University of Washington School of Medicine in Seattle. “Each procedure does this in a different way.”

According to Bruce M. Wolfe, MD, FACS, professor of surgery at Oregon Health & Science University in Portland, the way each operation accomplishes weight reduction is complex, and the amount of weight lost is highly variable within the population receiving that procedure.

In gastric bypass and sleeve gastrectomy, the patient’s stomach is cut and resewn to form a smaller stomach. Similarly, in biliopancreatic diversion with duodenal switch, the stomach is shaped into a tube. Gastric bypass is typically more restrictive than the sleeve in terms of the amount of food a patient can tolerate after surgery.

“The risks of [sleeve gastrectomy] were reduced, and the results were almost as good as the gastric bypass,” Wolfe said. “[Sleeve gastrectomy] has, according to the latest data, become the most commonly done bariatric surgical procedure in the United States.”

Gastric bypass includes not only the restrictive component, but also a bypass component in which part of the small intestine — the duodenum — is avoided, according to Louis J. Aronne, MD, FACP, the Sanford I. Wiell professor of metabolic research at Weill Cornell Medical College. This avoidance of the intestine leads to an average loss of about one-third of body weight.

The initial bypass may have particularly important beneficial effects for patients with diabetes, according to Arterburn.

“There are hormones that have been discovered that are related to this early part of the small intestine that are changed as a result of this bypass procedure, and it’s not entirely clear yet from the research, but people believe that the hormones that are affected by the actual bypass are part of the reason why that procedure does particularly well in patients with diabetes and that they may have earlier improvements in their blood sugar, than perhaps with the other procedures,” Arterburn said.

According to Aronne, in the sleeve gastrectomy procedure, the part of the stomach called the fundus is removed, which is the primary area where the hormone ghrelin is produced.

“Ghrelin increases appetite. When you remove that part of the stomach, as you lose weight, ghrelin levels can’t go up as they would normally, and that’s one reason [sleeve gastrectomy] improves weight loss as much as it does.”

The gastric band uses an adjustable band placed around the outside of the stomach to create a smaller stomach pouch. The band can be cinched or loosened in the clinic through a port beneath the skin to allow food to flow through the stomach more easily or more slowly.

Study results published in JAMA in 2014 revealed that sleeve gastrectomy was performed more often than any other bariatric surgery in Michigan in 2012, making it the most common type and leading bariatric surgery selected by patients with type 2 diabetes.

“That’s an important thing for doctors to know because it’s a relatively new procedure. It was introduced about 2008, so we don’t have much long-term follow-up data on that particular procedure in terms of how well people do keeping the weight off and how durable their improvements are in their diabetes,” Arterburn said.

He added that the procedure may be becoming more popular because it is easier to perform, safer and less complex than gastric bypass and has better results than the adjustable gastric band.

Patient indications

Currently, the NIH recommends bariatric surgery for adults with severe obesity (BMI ≥ 40 kg/m²) or a BMI of 35 kg/m² or higher with at least one obesity-related comorbidity.

In 2011, the FDA approved use of the adjustable gastric band for patients with a BMI of at least 30 kg/m² with at least one comorbidity linked to obesity.

“There’s no reason it can’t be done in that situation, but the fact is, it’s not being done that much, but it can be done,” Aronne said. “That makes sense. It’s the safest procedure, so for people with lower BMI it might make sense to do that.”

According to Sangeeta Kashyap, MD, a physician and bariatric researcher involved with the STAMPEDE bariatric trial in the department of endocrinology at the Cleveland Clinic, most health plans will cover bariatric surgery only for people with a BMI of at least 35 kg/m².

“At the Cleveland Clinic, our health plan allows people to have bariatric surgery with BMI 30 kg/m² or more if they have been under the care of an endocrinologist for 6 months and they’re medically refractory; that is, that diabetes control is not getting better despite increasing medications,” Kashyap said. “Moreover, BMI may not be the best clinical indicator of severity of metabolic disease and insulin resistance, especially in certain ethnicities predisposed to diabetes such as Eastern Asians, Middle Easterners, etc.”

According to Arterburn, there have been various recommendations internationally about changing the recommendations for diabetes, but currently the same guidelines are held.

Effectiveness for obesity and diabetes

According to Wolfe, the goal of bariatric surgery, in most cases, is to accomplish and sustain weight loss.

“Many people can, and do, lose weight short term with lifestyle intervention consisting of diet and increased physical activity, now possibly adding medication,” he said. “The reason for bariatric surgery is that it achieves more weight loss, and the weight loss is sustained much better than if surgery is not done.”

A study published in JAMA in 2015 by Arterburn and colleagues revealed ­­­­that patients with obesity who underwent bariatric surgery had a lower risk for mortality compared with those patients who did not undergo surgery. The researchers evaluated 2,500 adults who underwent bariatric surgery, as well as 7,462 matched controls managed without surgery, to determine the effect of bariatric surgery on long-term survival. Hypertension, dyslipidemia, arthritis, depression, gastroesophogeal reflux disease and fatty liver disease were common among the group that underwent surgery.

“The main implication of this study is that clinicians and patients with severe obesity can have greater confidence that bariatric surgical procedures are associated with better long-term survival than not having surgery,” Arterburn said. “Prior studies have demonstrated this finding in younger, predominately female populations, but our study confirms these findings in an older, predominately male cohort, with multiple comorbid health problems.”

According to Wolfe, biliopancreatic diversion with duodenal switch has been reported to achieve greater weight loss than gastric bypass.

“The extent to which that is true is hard to determine because we don’t have as much comparative data with that surgery,” he said. “Most would agree that the complication rate is somewhat higher than with the gastric bypass, and it’s exceedingly difficult to have detailed research to determine at what point the higher complication rate is justified because weight loss is better.”

According to Arterburn, the gastric bypass, sleeve gastrectomy and adjustable gastric band have all demonstrated that they can improve blood glucose, and patients may enter into diabetes remission after these procedures.

“The gastric bypass procedure, to date, seems to be the one that is perhaps the most effective for inducing the remission of diabetes and actually causing patients to come off medications,” Arterburn said.

Aronne echoed Arterburn in saying gastric bypass leads to the greatest improvements in blood glucose.

“The reason is that it’s not letting food touch the upper part of the intestine, the duodenum, and seems to have an independent effect on improving blood glucose,” he said. “That is why, when someone comes in and they have diabetes, we would usually choose the gastric bypass.”

The Surgical Therapy and Medications Potentially Eradicate Diabetes Efficiently (STAMPEDE) trial, conducted by Kashyap and colleagues, was developed to determine how gastric bypass and sleeve gastrectomy would fare compared with medical therapy in people with moderate obesity with more than half using insulin at trial entry. Participants were randomly assigned to one of the three interventions.

After intervention, participants were followed for outcomes at 1 year and 3 years.

“The gastric bypass led to remission of diabetes; that is, it led to a normal HbA1c level, and about 25% of the people were able to achieve a normal HbA1c level 3 years after the intervention without the use of any glucose-lowering drug,” Kashyap said. “In the sleeve gastrectomy group, the rate was a little less, and there wasn’t complete remission in the sense that some people still required some medication, but they required far less than they did before the intervention.”

Kashyap added that the medical arm showed improvement in glycemic control, but more medication was required.

Another important factor for bariatric surgery as a treatment for diabetes is the duration a person has had the disease.

“If we look at diabetes as being a chronic disease, it just stands to reason that the sooner you get to intervention the better results you’re going to have,” Morton said. “Just like cancer, you don’t want to wait to operate on someone whose cancer has disseminated. We would like to get to those patients sooner rather than later.”

Surgical control with diabetes and lower BMI

Currently under debate is whether patients with diabetes and a BMI less than 35 kg/m² should be eligible for bariatric surgery.

According to Wolfe, the short-term results are encouraging, but physicians need to know more about the long-term results before making widespread recommendations.

“We are talking about a lot of people. … If you look at the [BMI] 30 kg/m² to 35 kg/m² population, there are more people in that group than in the [BMI] 35 kg/m² to infinity group,” Wolfe said. “If you decide that a BMI of 30 kg/m² is an indication for surgery, you’re going to more than double the number of candidates. Is that what we’re going to do? The answer is no, we’re not operating on many of the people who are severely obese right now.”

Kashyap said the guideline for surgery of BMI 35 kg/m² or higher is a reasonable one.

“If someone is in the overweight [category], anywhere from [BMI] 28 kg/m² to 35 kg/m², clinicians have to be more aggressive in using antiobesity drugs. We have to be more aggressive with diabetic treatments that also result in weight loss,” she said. “If you have exhausted those things and the patient is still not improving or not responding, then you should consider doing things like banding, or if their BMI is 35 kg/m² or more consider the sleeve or gastric bypass.”

However, Morton added that at this point, more than 135 trials have been conducted to determine the effect of bariatric surgery on obesity, and many have revealed that surgery can induce a significant remission of diabetes, up to 82%.

“It’s an entirely viable option, obviously, for patients who have not had progress with dietary or pharmaceutical interventions, but for the right patient, in the right hands, bariatric surgery can be effective for patients with a BMI 30 kg/m² to 35 kg/m² and diabetes,” he said.

Donald T. Hess, MD, director of Boston Medical Center’s bariatric surgery program and assistant professor of surgery at Boston University School of Medicine, said the most important thing to remember about bariatric surgery is that it is the only therapy that is effective for obesity and diabetes.

“There have been many trials comparing surgery to physician-supervised weight-loss programs, and surgery always outperforms,” he said.

Complications and long-term care

“Bariatric surgery is an American surgical success story,” Morton said. “Mortality rates are now in the order of about 0.1%, which is equivalent to a knee replacement or removal of a gallbladder. With that in mind, we’re able to see those benefits clearly. That being said, the best place for [patients] to get bariatric surgery is at accredited centers that do demonstrate better outcomes.”

According to Morton, complications from bariatric surgery are comparable to any other medical intervention.

“There is always potential for risk and in order to enter into this situation, you have to do a comparison of the risks and benefits,” he said. “The data are clear that the benefits far exceed the risks.”

Results using data from the Bariatric Outcomes Longitudinal Database (BOLD) registry presented at Obesity Week 2014 revealed that readmission rates for all bariatric procedures were in the range of 5% within 30 days with the most common reason being nausea/vomiting, followed by dehydration, bleeding, surgical infections and obstruction. The readmission rates were lowest for gastric banding, followed by sleeve gastrectomy and gastric bypass.

According to Arterburn, the main concern with sleeve gastrectomy and gastric bypass is a leak where the intestines and stomach are joined after they are cut.

“It is rare. Less than 1% of patients have this occur, and the chance of dying in the first month after having either of these procedure is well less than 1%,” he said.

He added that the risk for mortality is even lower for the adjustable gastric band procedure, but the risk can vary. Results from a study published in JAMA Surgery, in which Arterburn was a researcher, revealed that gastric bypass led to higher risks for short-term complications and long-term subsequent hospitalizations. However, gastric bypass led to a decreased risk for subsequent interventions during the long term compared with adjustable gastric banding.

“There is no clear winner when comparing these two procedures,” Arterburn said. “Patients need to be well informed about these tradeoffs between the risk and benefits of the bariatric procedures, so that they can make their own personal assessment of what matters most to them.”

He added that the adjustable gastric band procedure results in less weight loss and fewer initial operative complications.

“It’s easy to put in a band, but the big problem is that in the longer term, there are many more procedures done to remove them than with the other procedures,” Arterburn said. “Some patients may not want as much weight loss gained with the gastric bypass; maybe looking at a smaller amount of weight loss would be acceptable to them and they may want less risk, so they lean toward the band, but they need to be aware that their chance of having a repeat operation is much higher.

“Other complications can be blood clots in the legs — which could also travel to the lungs — infections, bleeding; these also occur fairly rarely,” Arterburn said. “The combination of having all of these things, this whole risk, this set of complications, and staying in the hospital for a prolonged period of time occurs in about 4% of all patients.”

During a period of a year, it is possible for patients to develop complications due to deficiency of one or more minerals, Wolfe said.

“We do need to keep an eye on the potential for these nutritional deficiencies that are usually not common in this population,” he said. “If a patient gets behind on their supplements, we need to identify them and give them therapeutic intervention.”

Hess said for patients to have the highest chance of success after surgery, they should have at least an annual follow-up with their weight-loss surgery team where they will typically see both the surgeon and a dietitian.

According to Wolfe, long-term follow-up care is somewhat procedure-specific. However, most importantly, he said, is ensuring patients make changes in their eating habits.

“One of the great problems with human obesity is that those patients don’t have adequate signals to tell them they’ve had enough, so when they bring out the pie and ice cream, those people can still eat it at the end of the meal, even though they don’t need it and shouldn’t have it,” he said. “There are patterns, that if identified in patients and physicians counsel them, perhaps they will do better. That could be for any of these procedures because all of them are predicated on eating less.”

New developments

In January, the FDA approved the VBLOC vagal nerve-blocking therapy, delivered by the Maestro Rechargeable System, to treat obesity by targeting the nerve pathway between the brain and stomach to regulate feelings of hunger and fullness. It is the first obesity device to gain FDA approval since 2007 and is approved for patients aged 18 years and older with BMI from 40 kg/m² to 45 kg/m², or BMI from 35 kg/m² to 39.9 kg/m² with at least one obesity-related condition, who have not achieved weight loss with a program.

“Patients feel a sense of fullness that helps with weight loss,” Hess said. “The device is similar to a pacemaker with an implantable part and wires that attach to the stomach. The weight-loss results, however, are only modest. After 1 year, patients who had VBLOC lost about 25% of their excess weight. To compare other procedures, patients who have the lap band lose just under 40% and those with the gastric bypass are up around 70%.”

An FDA advisory committee found that 18-month data supported sustained weight loss and approved the device based on benefits outweighing risks in patients meeting criteria in the proposed indication.

“The safety of this was superior and the weight loss was inferior to standard bariatric procedures,” Wolfe said. “We’re going to see more of that.” – by Amber Cox

References:

• Arterburn DE, et al. JAMA. 2015;doi:10.1001/jama.2014.16968.
• Arterburn DE, et al. JAMA Surgery. 2014;doi:10.1001/jamasurg.2014.1674.
• NIH. U.S. Bariatric Surgery for Severe Obesity. Available at: win.niddk.nih.gov/publications/pdfs/gasurg12.04bw.pdf. Accessed March 2, 2015.
• Reames BN, et al. JAMA. 2014;doi:10.1001/jama.2014.7651.
• Sjöström L. J Intern Med. 2013;doi:10.1111/joim.12012.
• Sudan R, et al. Abstract T-3087-OR. Presented at: Obesity Week; Nov. 2-7, 2014; Boston.

For more information:

• Louis J. Aronne, MD, FACP, can be reached at Comprehensive Weight Control Center, 1165 York Ave., New York, NY 10065; email: ljaronne@med.cornell.edu.
• David E. Arterburn, MD, MPH, can be reached at Group Health Research Institute, 1730 Minor Ave., Suite 1600, Seattle, WA 98101; email: Arterburn.d@ghc.org.
• Donald T. Hess, MD, FACS, can be reached at Boston Medical Center, 88 E. Newton St., Suite D-507, Boston, MA 02118.
• Sangeeta Kashyap, MD, can be reached at Cleveland Clinic Main Campus, Mail Code F20, 9500 Euclid Ave., Cleveland, OH 44195; email: kashyas@ccf.org.
• John M. Morton, MD, MPH, FACS, can be reached at Stanford University School of Medicine, 300 Pasteur Drive, Room H3680, Stanford, CA 94305; email: morton@stanford.edu.
• Bruce M. Wolfe, MD, FACS, can be reached at wolfeb@ohsu.edu.

Disclosures:

• Aronne, Arterburn, Hess, Kashyap and Wolfe report no relevant financial disclosures. Morton reports being an investigator for the VBLOC FDA trial.

Should adolescents be referred for bariatric surgery?

Bariatric surgery may offer better disease control than other type 2 diabetes therapies in adolescents.

Type 2 diabetes is a chronic and disabling disease affecting adults and adolescents alike. Between 2001 and 2009, a 31% increase in prevalence of adolescent type 2 diabetes was seen in the United States. Conventional therapy for adolescents presents unique challenges in comparison with adults with type 2 diabetes. Most adolescents with type 2 diabetes are also obese or severely obese, making treatment especially difficult, especially given that traditional therapy with oral medication or insulin is most commonly associated with progressive weight gain.

Metformin, commonly used in both adults and adolescents, fails in more than 50% of adolescents over a 4-year period, while only 21% of adults with type 2 diabetes failed metformin therapy at 5 years. In addition to progressive decline in beta-cell function, rapid increases in prevalence of hypertension, dyslipidemia and microalbuminuria in adolescents have been documented despite standard type 2 diabetes therapy; these findings certainly underlie the accelerated vascular aging and, thus, poor long-term cardiovascular outcomes facing these youths.

Contemporary, controlled randomized prospective trials of surgical therapy, on the other hand, have shown dramatic early glycemic control, improvement in CV risk factors and impactful weight-loss responses for adults with type 2 diabetes. However, in adults, the durability of the response to surgical treatment may be limited and influenced by duration and severity of the disease at the time of operation. We do not yet know to what extent surgery may arrest or reverse CV or renal damage in those adults with type 2 diabetes. For all of these reasons, it is entirely appropriate to consider metabolic/bariatric surgery earlier in the treatment armamentarium for type 2 diabetes — and especially for select adolescents. However, well-designed prospective studies with hard endpoints that include a detailed assessment of target organ damage will be necessary to change minds and influence the place and timing of surgery in the treatment algorithm for adolescents.

Thomas H. Inge, MD, PhD, FACS, FAAP, is Surgical Director, Surgical Weight Loss Program for Teens; Director, Center for Bariatric Research and Innovation; Attending Surgeon, Cincinnati Children’s Hospital Medical Center; Professor, UC Department of Surgery. Disclosure: Inge reports no relevant financial disclosures.

Timing is everything.

There is no doubt that as of right now, bariatric surgery results in more weight loss and sustained weight loss than anything else we have available.

The reason that bariatric surgery should not be considered in adolescence is really one of timing: the time period of adolescence, which can be tumultuous and associated with a great degree of change; the timing within the life span — we don’t know whether the bariatric surgery we are offering today is durable and safe enough to have a sustained effect over decades; and the timing given the progress we have made in obesity management, finally being recognized as a chronic disease that requires sustained, biologically and psychologically based multifaceted management approaches, including more recently pharmacotherapy.

Bariatric surgery needs to be offered when it has the greatest chance of long-term success with minimal harm. Adolescence is not the right time to consider it. Teens live in the here and now — they struggle with adherence and follow-up, leaving them more vulnerable for long-term complications. It is not the right time because it is too early in the life span and questions around the long-term durability (more than 15 years) and safety of bariatric surgery loom large. It is not the right time because we finally have more to offer these teens and families as a medical community.

So let’s start by ensuring teens living with severe obesity have access to compassionate, holistic, multifaceted long-term care that may include pharmacotherapy, and should they continue to meet criteria for bariatric surgery, which many of them will — let’s prepare them to have the greatest chance of success with limited complications following that surgical intervention as adults.

Stasia Hadjiyannakis, MD, FRCPC, is a Pediatric Endocrinologist, Assistant Professor of Pediatrics, Medical Director of CHEO’s Centre for Healthy Active Living, Children’s Hospital of Eastern Ontario. Disclosure: Hadjiyannakis reports no relevant financial disclosures.