MedPage Today: Durable Weight Loss Seen After Bariatric Surgery in Teens

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Teenagers and young adults who underwent gastric bypass surgery for severe obesity showed overall reductions in weight and improvement in cardiometabolic risk factors 5 years later, according to two small follow-up studies.

The first study found a mean change in BMI of almost 30% (58.5 BMI at baseline versus 41.7 BMI at follow-up) in young people 5-12 years after surgery, reported Thomas Inge, MD, of Cincinnati Children's Hospital Medical Center, and colleagues in The Lancet Diabetes & Endocrinology.

The study also examined clinical events after the operation as safety indicators -- and found nearly half the patients had mild anemia or vitamin D deficiencies, the authors noted. On balance, they wrote, the benefits of surgery "were achieved with some attendant risks of micronutrient deficiencies and requirements for additional gastrointestinal procedures related to surgery, providing important data to inform treatment decisions for families."

Bariatric surgery has been used to treat severe obesity in adults, but access to surgical care has been "limited" for adolescents, the authors noted.

In a podcast released to the media, Inge said that "eat less and exercise more" is the standard recommendation for treatment of obesity in adolescents, but that may be changing.

"Over the past decade, increasing numbers of adolescents are seeking surgical treatment, because surgery has shown effectiveness in adults," he said. "Standard treatment does unfortunately fail with most, if not all, teenagers who are severely obese."

The Follow-up of Adolescent Bariatric Surgery at 5 Plus Years (FABS-5+) study looked at data from 58 of 74 U.S. young people in a prior study who had undergone Roux-en-Y gastric bypass surgery at ages 13-21 years (mean age 17). In the current study, the mean age of participants was 25 years, 64% girls, and 86% white. Mean follow-up period was 8 years.

Nearly half of participants had a 10% or greater reduction in BMI over this period. Nestor de la Cruz-Muñoz, MD, of University of Miami, who was not involved with the study, characterized the overall results as "excellent weight loss" for the follow-up period.

"This study reinforces that the medical condition of bariatric patients improves after surgery, and it shows this in a needy and growing population, adolescents," he told MedPage Today via email.

But even with the improvements in BMI, two-thirds of patients remained severely obese at follow-up with a BMI of 35 or higher. Not surprisingly, there was a significant relationship between baseline BMI and follow-up BMI (r=0.75, P<0.0001).

The authors said that for every 10-point increase in BMI at follow-up, participants had a 34% greater risk of developing dyslipidemia and a 46% higher risk of developing hypertension.

"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," they wrote.

Examining secondary outcomes, there were significant declines among the participants in the prevalence of several cardiometabolic risk factors:

  • Elevated blood pressure (47% versus 16%, P=0.001)
  • Dyslipidemia (86% versus 38%, P<0.0001)
  • Type 2 diabetes (16% versus 2%, P=0.03)

But 46% of participants reported mild anemia -- with two-thirds of patients recording low amounts of iron and ferritin, and 46% exhibiting below-average levels of hemoglobin. In addition, nearly 80% reported low vitamin D levels. Deficiencies in nutrient absorption are common after Roux-en-Y surgery and dietary adjustments to account for this are normally recommended.

Two patients from the original study died -- one of infectious colitis, who was not included in the follow-up study, and one 6 years following surgery, who died of "events unrelated to surgery."

One notable limitation of this study was the lack of a non-operative control group, which limited researchers' ability to assess the risk of not undergoing surgery.

Similar Findings in Sweden

The second study, by Torsten Olbers, MD, of the University of Gothenburg in Sweden, and colleagues, included a control group. The researchers also identified adult controls who had surgery, for "comparison of outcomes."

The Adolescent Morbid Obesity Surgery (AMOS) study examined 81 Swedish adolescents (mean age 16 years with a mean BMI of 45.5) who had Roux-en-Y gastric bypass surgery performed, 80 matched adolescent controls who were given "standard treatment" for their obesity, and 81 matched adult controls. Of the adolescents, girls were more common in the treatment group than among controls (65% versus 58%, respectively).

Overall, adolescents who underwent surgery had a 13-point reduction in BMI over 5 years of follow-up -- similar to the 12.3-point BMI reduction in adult controls, reported

By contrast, adolescent controls had a 3.3-point increase in BMI during the same time period.

De la Cruz-Muñoz pointed out that "the numbers of failure would likely be worse" in the adolescent control group, but 25% of adolescents "crossed over" and had surgery during the study period.

Cardiometabolic risk factors and comorbid conditions improved for adolescents in the treatment group, but not the adolescent control group.

There were no deaths in any group, although 25% of the adolescent treatment group reported additional abdominal surgical interventions, for acute intestinal obstruction and symptomatic gallstones.

Vitamin D deficiencies were observed in most of the controls as well as in the surgical patients. But surgical patients were more likely to show low ferritin, iron, or both at 5 years follow-up (66% versus 29% of controls).

"Though the treatment group had not had to be treated at 5-8 years, they will need to be followed to see if the conditions worsen after longer observation," said de la Cruz-Muñoz.

Geltrude Mingrone, MD, of Catholic University in Rome, Italy, agreed. In an accompanying editorial, she cautioned about "significant vitamin D deficiency" in both studies, as well as the possibility of early surgery affecting growth in adolescents.

"It is important that future national guidelines address the matter of the age at which bariatric surgery should be performed in adolescents," she wrote. "Accurate multidisciplinary care and frequently planned follow-up visits should be provided to ensure the best standard of care for these young patients in such a delicate period of life."

Limitations to the second study included that it was non-randomized and used "pragmatic, non-standardized, conservative" treatment for the control group.

Inge and colleagues were partially supported by grants from Ethicon Endosurgery and the NIH. Inge disclosed support from Ethicon Endosurgery and Sanofi. Other co-authors disclosed support from Abbott Australasia, Biogen Idec, Ely Lilly, iNova Pharmaceuticals, Allergan, Apollo Endosurgery, Bariatric Advantage, Nestle Australia, Novo Nordisk, BUPA, and Covidien. Olbers disclosed support from Ethicon Endosurgery, AstraZeneca and Sanofi-Aventis. Other co-authors disclosed support from Nestlé, Itrim, a commercial provider of non-surgical weight-loss services, Pfizer, Cambridge Weight Plan, Novo Nordisk, AstraZeneca, Pfizer, Sanofi-Aventis, Roche, Strategic Health Resources, Oriflame Wellness, and Sigrid Therapeutics. Mingrone disclosed no relevant financial relationships.

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