Roux-en-Y Gastric Bypass Surgery in Type 1 Diabetes Patients

How do the long-term benefits and complicating factors of gastric bypass surgery in type 1 diabetes patients compare to those with type 2?

Gastric bypass surgery is a procedure performed by doctors in the hope of assisting the small intestine in patients with diabetes to get rid of excessive amounts of glucose that their bodies naturally produce. After the gastric bypass surgery is complete, the small intestine spontaneously produces GLUT-1 molecules that help the body use glucose.  This molecule is not generally seen in the small intestine of adults, but only in a fetus.  Gastric bypass is known to improve type 2 diabetes symptoms and start an impressive weight loss journey for patients with diabetes or obesity. This study’s purpose was to see the long-term benefits and complicating factors of bariatric surgery in specifically type 1 diabetes. Recent studies have also been conducted to see if gastric bypass surgery cured type 2 diabetes. David Heitz wrote an article in October of 2018 explaining the benefit of the surgery. In his report, he said that Dr. Nicholas Stylopoulos, the principal investigator at the Division of Endocrinology of Children’s Hospital Boston and Boston Medical School, discovered that he found that the cure after the gastric bypass lies in the intestine.  Previous researchers have shown that gastric bypass surgery helps resolve diabetes even before the weight loss process occurs. 

The nationwide, matched, observational cohort study of bariatric surgery in type 1 diabetes was completed in the years 2007 to 2013. During this time, two organizations conjoined with the Swedish National Diabetes Register and Scandinavian Obesity Surgery Registry to study two specific groups of individuals they have had an experience with. One group consisted of patients with type 1 diabetes and obesity who did have the Roux-en-Y gastric bypass surgery. The other group consisted of type one diabetes and obesity patients who matched for age, sex, BMI, and calendar time but did not have the gastric bypass surgery performed. In addition, the study checked for a list of specific outcomes, including all-cause mortality, cardiovascular disease, stroke, heart failure, and hospitalization for severe hypo or hyperglycemic episodes, amputations, psychiatric disorders, and kidney function change, and substance abuse. 

The results consisted of 387 individuals who did have gastric bypass surgery and 387 patients who did not have the gastric bypass surgery performed, and had a follow-up of up to 9 years. The analysis showed that the risk of cardiovascular disease (hazard ratio 0.43; 95% CI 0.20-0.9), cardiovascular deaths (hazard ratio 0.15; 95% CI 0.03-0.68), hospitalization due to heart failure (hazard ratio 0.32; 95% CI 0.15-0.67) and stroke (hazard ratio 0.18; 95% CI 0.04-0.82) for the Roux-en-Y gastric bypass group were all substantially lower than the group of patients who did not undergo the gastric bypass surgery. However, there was a noticeably higher risk for severe hypo- and hyperglycemic events (hazard ratio 1.99; 95% CI 1.07-3.72) and extreme substance abuse (hazard ratio 3.71; 95% CI 1.03-3.29) all noticed after surgery. 

The nationwide, matched, observational cohort study exemplified that gastric bypass surgery may have similar benefits on the risk of cardiovascular diseases and mortality in patients with type 1 diabetes and patients with obesity, and patients with type 2 diabetes and obesity.  Although there are benefits shown, there is also some close monitoring that is necessary for these patients. Patients need to be closely monitored for severe adverse effects like substance abuse and glycemic control after surgery. Some studies suggest gastric bypass surgery will lower a patient’s HbA1c by 3-4%.

Practice Pearls:

• Gastric bypass surgery is beneficial in type 1 and type 2 patients at risk for cardiovascular disease, stroke, heart failure, amputations, psychiatric disorders, kidney function, and all-cause mortality.
• Gastric bypass surgery patients should be closely monitored after surgery for hypo- and hyperglycemic control and substance abuse.
• Gastric bypass surgery can also be used in patients with obesity for weight loss.

“Potential Benefits and Harms of Gastric Bypass Surgery in Obese Individuals with Type 1 Diabetes: A Nationwide, Matched, Observational Cohort Study.” MDLinx, 8 Oct. 2020  

“Gastric Bypass Surgery in Severely Obese Type 1 Diabetic Patients.” Diabetes Care, American  Diabetes Association

Heitz, David. “How Does Gastric Bypass Surgery Cure Type 2 Diabetes?” Healthline, 7 Oct. 2018,  www.healthline.com/health-news/aging-how-gastric-bypass-eliminates-type-2-diabetes-072913 .

“Pros and Cons of Gastric Bypass Surgery in Individuals with Obesity and Type 2 Diabetes: Nationwide, Matched, Observational Cohort Study.” BMJ Open, British Medical Journal Publishing Group, 1 Jan. 2019,  

Mehr, Stanton. “Can Gastric Bypass Surgery Be a Cure for Diabetes Mellitus?” AJMC, 21 July 2014,

www.ajmc.com/view/can-gastric-bypass-surgery-be-a-cure-for-diabetes-mellitus .

A’Kira Shavers, PharmD Candidate 2021, South College School of Pharmacy