Short and long-acting GLP-1 receptor agonists as an add-on treatment in type 2 diabetes

The main objective of this analysis was to determine the benefit of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) compared to insulin treatment in patients with type 2 diabetes who were receiving treatment with oral glucose-lowering medications (OGLM – used to produce insulin in patients who cannot produce enough by themselves).

The authors concluded that slightly better blood sugar control and weight loss was achieved when GLP-1 RAs were added to OGLM compared to insulin treatment. Benefits were also evident in blood pressure, heart rate and hypoglycemia (dangerously low bloog glucose). 

GLP-1 RAs (such as Victoza) are a common treatment in type 2 diabetes. They increase insulin secretion to improve blood sugar levels and control and to reduce body weight. GLP-1 RAs can be short-acting (lasts for 2-5 hours) or long-acting (lasts for 12 hours to several days). Insulin treatment is a standard treatment in diabetes that involves administering either rapid-acting or long-acting insulin. Rapid-acting insulin is quickly absorbed and is used during mealtimes. Long-acting insulin is released slowly over a period of 8 to 24 hours and supplies the baseline insulin levels that are needed during the day. 

Both GLP-RAs and insulin can be used as add-on treatments in patients already being treated with additional medications, such as OGLMs. OGLMs include medications such as metformin (Glucophage) and sulfonylureas (stimulate the pancreas to produce more insulin). Add-on treatments are often necessary in patients who do not have adequate control over their blood sugar levels. Insulin is more commonly prescribed as an add-on treatment. Numerous studies have shown that GLP-RAs are also effective in managing and controlling diabetes, as well as reducing weight, blood pressure and heart rate.

The aim of this review was to analyse existing articles and compare the published effects of GLP-1 RAs to insulin treatment in patients with type 2 diabetes currently receiving OGLMs. 

23 publications were included in this review. From this, 3,976 patients were treated with GLP-1 RAs as an add-on treatment to OGLMs. 3,508 patients were treated with insulin as an add-on treatment to OGLMs. 

Short-acting GLP-1 RAs had a similar effect on HbA1c levels (measurement of blood sugar levels over the past three months) compared to insulin. Long-acting GLP-1 RAs caused a significantly greater reduction in HbA1c levels (0.17%) compared to insulin. Insulin treatment decreased fasting plasma glucose levels (glucose levels after a period without food or drink) more so than GLP-1 RAs. GLP-1 RA treatment reduced overall body weight, while insulin led to an increase in weight.

Short-acting GLP-1 RAs resulted in the greatest weight loss compared to insulin. There was a reduction in blood pressure in patients treated with GLP-1 RAs. Patients treated with insulin did not experience a reduction or change.

Patients experiencing hypoglycemic episodes (episodes of extremely low blood sugar levels) was 34% lower in patients treated with GLP-1 RAs. This was compared to insulin treated patients. Heart rate was higher in patients treated with GLP-1 RAs compared to patients treated with insulin. 

The authors concluded that slightly better blood sugar control and weight loss was achieved when GLP-1 RAs were added to OGLMs compared to insulin treatment. Benefits were also evident in blood pressure, heart rate and hypoglycemia.