Comparison of Gastric Bypass Outcomes in Adolescents and Adults Five Years Post Op

The study findings explore the gastric bypass outcomes of different age groups in hopes of learning more about the procedure and the potential risks and benefits that come with it.

Gastric bypass is an elective surgery for patients with difficulties in losing weight or keeping the weight off after losing it. Gastric bypass is a very effective procedure that, with the help of a strict dietary regimen and an exercise program, can help patients with obesity lose up to 60-80% of their long-term excess weight. With the global effort to promote weight loss, gastric bypass has been added to a provider’s arsenal to help promote that effort. The World Health Organization has classified approximately 500 million adults and 42 million children under the age of 5 years worldwide as having obesity.

Gastric bypass works through several gastrointestinal mechanisms. Firstly, because the new stomach pouch is smaller than a normal stomach, the patient eats considerably smaller meals. It causes the patient to reach satiety more rapidly in comparison to a patient that hasn’t undertaken the elective procedure. An additional mechanism that can lead a patient to weight loss is the decrease in caloric intake. The bypass reroutes the food so that it is not digested in the stomach and small intestines but gets transported to a small pouch that was surgically implanted. This decreases the number of calories that are ingested and digested, and decreases the absorption of the food that an otherwise normal body would have absorbed.

Gastric bypass is not a quick fix to weight loss and requires strict adherence to diet and exercise. Criteria that would make gastric bypass a recommended procedure is patients with a BMI of 40 or more. Patients with a BMI of 40 or greater are referred to as having morbid obesity, and are around 100 pounds greater than their recommended weight. Other candidates for gastric bypass include patients with a BMI of 35 or greater who also suffer from medical conditions that are exacerbated by their obesity and may potentially improve if the patient loses the excess weight. Conditions that could greatly improve with weight loss include obstructive sleep apnea, type 2 diabetes mellitus, and cardiovascular disease.

Additionally, bariatric surgery in patients of advanced age (65 years or greater) or adolescents (younger than 18 years) is controversial but is not considered an absolute contraindication. When the patient’s comorbidity is severe and debilitating, surgery may be considered. This article expands on the comparisons, potential adverse effects, and overall outcomes of electing to partake in Roux-en-Y Gastric Bypass (RYGB) at the age of adolescence versus electing to do the surgery as an adult.

In this cohort trial, 161 patients of adolescent age were enrolled for six years, from 2006 to 2012, while 396 patients of adult age were enrolled in 3 years, from 2009 to 2012. The two cohorts were placed in related, but independent studies. The main objective of the study was to compare the 5-year weight loss outcomes of the two cohorts, along with the progression or elimination of the coexisting conditions that the patient may have suffered from before the surgery.  Rates of death, subsequent abdominal operations, and select micronutrient levels (up to 2 years after surgery) were also compared between the two cohorts.

When analyzed, the study found that there was no significant change in weight between the adolescent cohort (−26%; 95% confidence interval [CI], −29 to −23) and the adult cohort (−29%; 95% CI, −31 to −27) 5 years after surgery (P=0.08). Five years after electing to partake in the RYGB procedure, 60% (95% CI, 51 to 72) of adolescents and 76% (95% CI, 71 to 81) of adults maintained a weight reduction of 20% or more (P=0.02). In the analysis of micronutrients and patient labs, there were improvements in HDL cholesterol and Triglyceride levels for both cohort groups, but there was not a significant difference when both groups are compared to each other.

The comorbidities analysis of the trial was significant in that the prevalence of diabetes in adolescents decreased from 14% to 2% five years post-operation (95% CI, 9 to 20) and the prevalence of diabetes in the adult cohort decreased from 31% to 12% 5 years post-operation (95% CI, 27 to 36). Before the RYGB procedure, 88% of adolescents and 79% of adults in the study were taking medications for diabetes. By year 5, zero adolescent patients were taking medications, while the adult cohort decreased to 26% (P<0.001). The remission of diabetes, however, differed significantly between adults and adolescents. With the baseline data gathered from patients about their comorbidities, 86% (95% CI, 70 to 100) of adolescents and 53% (95% CI, 42 to 67) of adults were no longer classified as diabetic patients (having an A1C of greater than 6.5). Furthermore, adolescent patients were 27% more likely than the adults to have remission of diabetes post-operation.  

In the hypertension analysis of the article, it was found that patients of the adolescent cohort were 51% more likely to achieve remission of hypertension (relative risk, 1.51; 95% CI, 1.21 to 1.88; P<0.001) in comparison to that of their adult counterparts. The remission of hypertension was defined as a systolic of less than 140 and a diastolic of less than 90. For the death and subsequent abdominal procedures analysis of the article, it was found that three patients of the adolescent cohort died, while seven patients of the adult cohort died. It was found that the percent of patients that underwent subsequent abdominal operations in years 1 through 5 post-operation were similar (30% of adolescents vs 27% of adults in year 1; 37% and 32%, respectively, in year 2; 13% and 14% in year 3; 11% and 20% in year 4; and 9% and 7% in year 5).

A gastric bypass is an option that can help thousands of patients who are affected by obesity and have difficulties with conventional weight loss methods. This journal article presents a compelling case for the use of RYGB in patients at a younger age versus patients of advanced age due to the reduction and remission of the comorbidities that are often manifested in patients with obesity. Providers must use conventional weight loss techniques in patients as first-line therapy before considering an elective procedure. A gastric bypass, like many other procedures, carries a potential risk of complication and mortality. Patient education and motivation need to be stressed to patients that undergo gastric bypass because the procedure is not a cure-all and requires strict adherence to both exercise and dietary regimens.

Practice Pearls:

• Although the BMI calculation is a good reference tool, several other factors should be taken into account when assessing a patient’s health.
• Encourage patients to keep their BMI between 18.5 and 24.9.(normal weight range)
• Patients should strive to diet and exercise to prevent comorbidities from occurring like diabetes, hypertension, and cardiovascular disease.

References for “Comparison of Gastric Bypass Outcomes in Adolescents and Adults Five Years Post Op”:

American Society for Metabolic and Bariatric Surgery. (n.d.). Bariatric Surgery Procedures | ASMBS. Retrieved June 30, 2019, from https://asmbs.org/patients/bariatric-surgery-procedures

The World Health Organization. (n.d.). Obesity and overweight. Retrieved June 30, 2019, from https://www.who.int/mediacentre/factsheets/fs311/en/

US National Library of Medicine. (2018, June 21). Gastric bypass surgery: MedlinePlus Medical Encyclopedia. Retrieved June 30, 2019, from https://medlineplus.gov/ency/article/007199.htm

Inge, T. H., Courcoulas, A. P., Jenkins, T. M., Michalsky, M. P., Brandt, M. L., Xanthakos, S. A., … Helmrath, M. A. (2019). Five-Year Outcomes of Gastric Bypass in Adolescents as Compared with Adults. New England Journal of Medicine,380(22), 2136-2145. doi:10.1056/nejmoa1813909

Usif Darwish, PharmD Candidate, Florida A&M University, College of Pharmacy & Pharmaceutical Sciences