Current and future impact of clinical gastrointestinal research on patient care in diabetes mellitus

Abstract

The worldwide rise in the prevalence of obesity supports the need for an increased interaction between ongoing clinical research in the allied fields of gastrointestinal medicine/surgery and diabetes mellitus. There have been a number of clinically-relevant advances in diabetes, obesity, and metabolic syndrome emanating from gastroenterological research. Gastric emptying is a significant factor in the development of upper gastrointestinal symptoms. However, it is not the only mechanism whereby such symptoms occur in patients with diabetes. Disorders of intrinsic pacing are involved in the control of stomach motility in patients with gastroparesis; on the other hand, there is limited impact of glycemic control on gastric emptying in patients with established diabetic gastroparesis. Upper gastrointestinal functions related to emptying and satiations are significantly associated with weight gain in obesity. Medications used in the treatment of diabetes or metabolic syndrome, particularly those related to pancreatic hormones and incretins affect upper gastrointestinal tract function and reduce hyperglycemia and facilitate weight loss. The degree of gastric emptying delay is significantly correlated with the weight loss in response to liraglutide, a glucagon-like peptide-1 analog. Network meta-analysis shows that liraglutide is one of the two most efficacious medical treatments of obesity, the other being the combination treatment phentermine-topiramate. Interventional therapies for the joint management of obesity and diabetes mellitus include newer endoscopic procedures, which require long-term follow-up and bariatric surgical procedure for which long-term follow up shows advantages for individuals with diabetes. Newer bariatric procedures are presently undergoing clinical evaluation. On the horizon, combination therapies, in part directed at gastrointestinal functions, appear promising for these indications. Ongoing and future gastroenterological research when translated to care of individuals with diabetes mellitus should provide additional options to improve their clinical outcomes.

Keywords: Bariatric surgery; Diabetes mellitus; Gastric bypass; Gastric emptying; Obesity; Weight loss.

Figure 1

Comparison between bariatric surgical procedures. The top cartoon depicts the adjustable gastric band which limits the types of food consumed postoperatively by patients. The middle cartoon depicts the vertical sleeve gastrectomy which limits the volume of food consumed postoperatively by patients. The lower cartoon depicts the Roux-en-Y gastric bypass which limits volume of food consumed, may alter absorption of macronutrients, and alters release of intestinal incretins (Reproduced with the permission of Nature Publishing Group from Bal et al. Nature Rev Endocrinol 2012; 8: 544-556).