Cautious Optimism on Gastric Bypass Surgery in Teenagers

Liam Davenport

January 10, 2017

Gastric bypass surgery can help obese adolescents lose weight, and many maintain the weight loss over the longer term, but there may be ongoing nutritional deficiencies and the need for further surgery, suggest the results of two new studies.

The first, by Thomas Inge, MD, PhD, director, Center for Bariatric Research and Innovation, Cincinnati Children's Hospital Medical Center, Ohio, found that, 8 years following Roux-en-Y gastric bypass, adolescents maintained an average weight loss of approximately 30%.

And in the second study, Torsten Olbers, MD, PhD, researcher, department of gastrosurgical research and education, University of Gothenburg, Sahlgrenska University Hospital, Sweden, also showed that the procedure can achieve a weight loss of around 28% in adolescents, matching that achieved in adults.

However, gastric bypass surgery was associated with vitamin D and B12 deficiencies and mild anemia and, in some cases, further abdominal surgery was needed. In addition, a substantial proportion of teenagers in both studies remained obese at follow-up.

The results, which were published online in Lancet Diabetes & Endocrinology on January 5, echo those of a recent investigation suggesting that Roux-en-Y gastric bypass for morbid obesity may be associated with ongoing gastrointestinal complaints.

As reported by Medscape Medical News, the cross-sectional comparison of 249 patients who underwent the surgery with a similar number of morbidly obese controls showed that indigestion, flatulence, and intolerances to certain foods were common at 2-year follow-up among the surgical patients.

Cutoff Age Needed to Ensure Teens Comprehend Postsurgery Requirements

In a comment accompanying the two new analyses, Geltrude Mingrone, MD, PhD, department of internal medicine, Catholic University, Italy, points out that neither dietary and lifestyle changes nor medical treatments "have much of an effect in adolescent populations because of poor adherence."

"Additionally, intensive behavioral weight-loss interventions that are effective at reducing [body mass index] BMI in adolescents who are overweight or obese have diminished effectiveness for those with severe obesity."

While noting that "no other approaches" are able to match bariatric surgery for weight loss over time, she cautions that "we should bear in mind that adolescents do not have the same awareness as adults normally do of the absolute obligation to be careful, attentive, and [undergo] lifelong medical monitoring."

Speaking to Medscape Medical News, Dr Mingrone said that "we need also to be cautious before deciding when adolescents should be operated" on, adding: "My opinion is that it would be better to wait until these young patients are aged at least 16 years, because the major problem is that there is a reduction in height growth."

Highlighting the fact that some of the patients in these newly published studies were aged just 13 years, "so they should grow very fast at that age," she said she believes "scientific societies need "to discuss this problem and decided which is the best [age] cutoff for performing bariatric surgery."

It is particularly important to discuss these issues as adolescents have poor compliance with weight-loss interventions, she stresses.

"If the family is very present and they follow these young people, probably it would be better," she said, "but, in particular in the United States where the family network is scarce, it would be important to postpone the operation until the adolescent can judge if they want to follow a certain regimen and take medication for their whole life."

Gastric Bypass in Adolescence: Greater Long-Term Benefit Than Risk

In the first paper, the researchers studied long-term outcomes among 58 young people taking part in the Follow-up of Adolescent Bariatric Surgery at 5 Plus Years (FABS-5+) extension study, who had undergone Roux-en-Y gastric bypass for clinically severe obesity at the Cincinnati Children's Hospital, a pediatric academic medical center.

The participants, who had a mean age at baseline of 17.1 years and a mean BMI of 58.5 kg/m2, underwent the procedure between 2001 and 2007.

During the first 12 months after surgery, BMI decreased by an average of 22.8 kg/m2. After a mean follow-up of 8.0 years, the mean reduction in BMI was 16.9 kg/m2, or a mean sustained weight loss of 49.9 kg.

Among the 57 participants with complete long-term data, one had achieved a healthy body weight at final follow-up, 10 were overweight, 10 had class 1 obesity (BMI 30 to <35), with a further 36 (63%) still being severely obese, with a BMI of ≥35 kg/m2.

The team notes: "This finding raises a fundamental question of whether higher residual BMI at long-term follow-up — despite previous substantial weight loss — heightens the risk of adverse future health outcomes."

Indeed, analysis revealed that every 10-kg/m2 increase in BMI at long-term follow-up was associated with a 34% greater risk of dyslipidemia (P = .0060), a 46% greater risk of hypertension (P = .0084), a 66% increase in high sensitivity C-reactive protein levels (P = .0015), and a 25% rise in insulin concentrations (P = .004).

The results nevertheless showed that, between baseline and long-term follow-up, there was a significant reduction in the prevalence of increased blood pressure following Roux-en-Y gastric bypass, from 47% to 16% (P = .001).

There were also significant reductions in the prevalence of dyslipidemia, from 86% to 38% (P < .0001) and type 2 diabetes, from 16% to 2% (P = .03).

At final follow-up 46% of the participants had mild anemia that did not require intervention, 45% had hyperparathyroidism, and 16% had low vitamin B12 levels.

The team adds: "Although some participants reported undergoing additional procedures, most were not related to abdominal or gastrointestinal problems."

They conclude: "On balance, these data suggest that bariatric surgery done in adolescence provides greater long-term benefit than risk. Additional research will be needed to ascertain whether the health benefits recorded will translate into improved life expectancy."

Adolescent Gastric Bypass Surgery Must Be Performed in Specialist Centers

In the second paper, 81 adolescents with a mean age of 16.5 years and a mean BMI of 45.5 kg/m2 who underwent Roux-en-Y gastric bypass at three specialized pediatric obesity treatment centers in Sweden were studied.

The team also recruited 80 BMI-, age-, and sex-matched adolescents who had conservative treatment for obesity rather than surgery and 81 BMI- and sex-matched adults controls aged 35 to 45 with severe obesity who had also undergone Roux-en-Y gastric bypass.

Over 5 years of follow-up, the adolescents who underwent surgery had a mean reduction in BMI of 13.1 kg/m2, compared with a mean increase in BMI of 3.3 kg/m2 in the adolescent controls and a mean reduction in BMI of 12.3 kg/m2 in the adult surgical group.

After 5 years, 72% of adolescent surgical patients, 7% of adolescent controls, and 76% of adult controls achieved a BMI of ≤35 kg/m2. Moreover, 27%, 3%, and 44%, respectively, were no longer obese.

While 69% of adolescent surgical patients and 85% of adult surgical patients achieved a total body-weight loss of ≥20%, 69% of adolescent controls gained body weight.

And once they reached adult eligibility, 25% of adolescent controls opted to have bariatric surgery.

All measures of glucose homeostasis improved across 5 years among the adolescent surgical patients, as did comorbidities and cardiovascular risk factors. Furthermore, the three cases of type 2 diabetes at baseline in this group were in remission at 5-year follow-up.

However, 25% of adolescent surgical patients had additional abdominal surgery for complications from the bypass or as a result of rapid weight loss, including bowel blockage (11 cases) and gallstones (nine cases), and 72% had some form of nutritional deficiency. Healthcare consumption during follow-up was higher among adolescent surgical patients than adolescent controls, at 16.1 vs 2.8 hospital days and 14.6 vs 10.0 outpatient visits.

The team says the evidence now "seems sufficiently mature to consider formal integration of bariatric surgery into treatment pathways for adolescents with severe obesity."

Nevertheless, they note that such surgery "must be done within appropriate specialist multidisciplinary programs that are specifically designed to accommodate adolescent patients and provide long-term follow-up and support."

They conclude: "Future challenges include refinement of indications and contraindications, identification of ideal target age groups, and optimization of postoperative support. We must also closely monitor patients for potential long-term adverse effects of surgery, across decades rather than years."

And in a Lancet press release, Dr Inge surmises: "These two manuscripts clearly document long-term benefits of adolescent bariatric treatment but also highlight several nutritional risks. Now it is important to focus on delivery of the substantial health advantages of surgery while minimizing these risks. Since there are currently two effective bariatric procedures, namely gastric bypass and vertical sleeve gastrectomy, we are currently examining the outcomes of both procedures to determine what is best for adolescents."

Dr Inge has received research grant funding for the FABS study and the FABS-5 study from Ethicon Endosurgery and has served as a consultant for Sanofi. Disclosures for the coauthors are listed in the paper. Dr Olbers has received consulting fees for participation in a global advisory board and a lecturing fee from Ethicon Endosurgery unrelated to the present work; lecturing fees from AstraZeneca and Sanofi unrelated to the present work; and disposable surgical equipment from Ethicon Endosurgery for use in study participants. Disclosures for the coauthors are listed in the paper. Dr Mingrone has no relevant financial relationships.

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Lancet Diabetes Endocrinol. Published online January 5, 2017. Inge article, Olbers article, Editorial

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