Glucagon-like peptide 1 use in patients with type 1 diabetes

The authors aimed to review the use of glucagon-like peptide 1 (GLP-1) agonists in patients with type 1 diabetes. The authors concluded that the use of GLP-1 agonists should be considered in patients with type 1 diabetes who are overweight or obese and not at target blood sugar control. Tolerability in patients, however, was a potential concern. 

Insulin treatment is standard in diabetes. However, treatment with insulin alone can fail to control long-term complications (eye problems, kidney disease, nerve disease causing numbness). With the recent prevalence of obesity resulting in insulin resistance, it is now necessary to find new, innovative treatment approaches.

Newer treatments include GLP-1 agonists, which work by increasing insulin secretion to result in improved blood glucose control and reduced body weight. Examples include exenatide (Byetta – administered twice daily through the skin layers ) and liraglutide (Victoza – administered once daily). GLP-1 agonists are often used in type 2 diabetes. Their effectiveness in type 1 diabetes is not yet clear.

The authors aimed to review the benefit of GLP-1 agonists in patients with type 1 diabetes. 9 clinical trials including 290 patients were examined in this review.  

Exenatide treatment was examined in three clinical trials ranging from 3 months to 18 months. These trials compared exenatide use with insulin to insulin alone, or to other treatments such as sitagliptin (Januvia). Each trial reported increased sensitivity to insulin in those treated with exenatide. This was associated with a lowered daily dose of insulin, weight loss and delayed gastric emptying (food emptying from the stomach).

Liraglutide treatment was examined in six clinical trials. Each trial reported that when insulin and liraglutide was used in combination, HbA1c levels (a measurement of average blood glucose levels over the past 3 months) were consistently lowered by 0.2% to 0.5%. However, this decrease was not always statistically significant.

A weight loss of 2.3 to 6.8 kg was witnessed over a 4-week to 24-week period. This was seen regardless of baseline body weight or body mass index (BMI – measured using weight and height). However, it was more pronounced in overweight patients. Other side effects included gastrointestinal problems, including nausea.

The authors concluded that the use of GLP-1 agonists should be considered in patients with type 1 diabetes who are overweight or obese and not at target blood sugar control. Tolerability in patients, however, was a potential concern.