Cardiometabolic risk factors, fasting insulin levels decreased “dramatically” from 31.7 to 7.4 mU/L
Gastric Bypass Has Weight-Independent Metabolic Benefits
December 8, 2011 (Dubai, United Arab Emirates) — Gastric bypass surgery normalized metabolic, inflammatory, and vascular risk markers in obese adolescents despite continued obesity 2 years after surgery, according to results of the Swedish Adolescent Morbid Obesity Study reported here at the International Diabetes Federation (IDF) World Diabetes Congress.
“Bypass surgery seems to have a weight-independent effect, probably due to the release of GLP-1 [glucagon-like peptide-1],” said Emilia Hagman, a PhD student at the Karolinska Institutet, in Stockholm, Sweden, who reported the findings on behalf of her colleague Claude Marcus, MD, PhD, who was unwell.
The nationwide, prospective, nonrandomized study included 81 adolescents (28 males, 53 females) aged 13 to 18 years (mean age, 16.5 years) who underwent laparoscopic gastric bypass surgery between June 2006 and April 2009.
Individuals with mental retardation, severe depression, severe eating disorders, and a history of drug abuse were excluded. However, patients with attention-deficit disorder and minor psychiatric illness were included, and, in fact, 80% of the cohort had some abnormal psychiatric background, Ms. Hagman said.
At baseline, the mean weight of the patients was 133 kg and mean body mass index (BMI) was 45.5 kg/m2.
At 2 years after surgery, after a mean weight loss to 89 kg, the mean BMI of patients remained in the obese range at 30 kg/m2 but was still significantly lower than at baseline (P < .001), she reported.
In terms of cardiometabolic risk factors, fasting insulin levels decreased “dramatically” from 31.7 to 7.4 mU/L, said Ms. Hagman.
Additionally, hemoglobin A1C decreased from 4.37% to 4.17%, fasting glucose from 5.1 to 4.9 mmol/L, low-density lipoprotein cholesterol from 2.6 to 2.0 mmol/L, triglycerides from 1.2 to 0.9 mmol/L, apolipoprotein B from 1.3 to 0.7 g/L, C-reactive protein from 7.2 to 2.5 nmol/L, white blood cell count from 8.2 to 6.5 x 109/L, and blood pressure from 124/78 to 117/71 mm Hg (all changes P < .001).
Meanwhile, both apolipoprotein A increased from 1.13 to 1.33 g/L and high-density lipoprotein cholesterol increased from 1.09 to 1.37 mmol/L (both changes P < .001), she said.
Gastric bypass was chosen over gastric banding because of its better results for long-term weight loss, Ms. Hagman said. “We also know that GLP-1 release is increased with bypass and is unchanged by gastric banding, insulin levels reduce immediately after bypass as opposed to being dependent on weight loss with banding, and diabetes remission is 80% at 2 years post-bypass versus 55% after banding,” she added.
Roughly 43% of patients regained some weight between 1 and 2 years after surgery, but this gain did not reverse the positive cardiometabolic changes. However, mean insulin levels were higher among patients who gained weight than in those who did not.
The treatment was generally well tolerated, with quality of life improved for all measures on the Short-Form Health Survey-36, she said.
Adverse events associated with the procedure included reoperation due to gall bladder surgeries (n = 7), intra-abdominal hernia (n = 2), unwanted pregnancy (n = 2), decreased self-esteem (n = 5), self-destructive behavior (n = 2), eating disorders (n = 2), drug abuse (n = 2), and suicide attempts (n = 2). However, the most common adverse effect was low vitamin levels, seen in 55 patients despite prescribed supplementation, she said.
“One has to remember that the psychosocial background for morbidly obese adolescents is already problematic,” she said.
“Overall, if you’re looking at the metabolic parameters, there’s no question that they improve. The question is long-term outcome,” said Arya Sharma, MD, PhD, professor of medicine and chair of Obesity Research and Management at the University of Alberta, Edmonton, Canada, who co-chaired of the session at which the study was presented.
“With some of these kids being as young as 13 years, the fact that about 50% of them developed vitamin deficiencies speaks to some of the challenges of gastric bypass surgery,” he told Medscape Medical News.
“The problem with a band is that it requires a high degree of patient compliance, so you don’t get the kind of weight loss with a banding operation. So, even with the risk of nutritional deficiencies, this study probably doesn’t speak against doing bypass, because I know that [these children] are in a very desperate situation and that without treatment or losing weight these kids probably don’t have very much of a future.”
International Diabetes Federation (IDF) World Diabetes Congress 2011. Abstract #O-0531. Presented December 7, 2011.