Background: Clinical use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) is well established as add-on therapy to oral medications and basal insulin. However, there is little published data regarding the use of GLP-1 RAs for longer than 12 months in patients taking basal/bolus insulin regimens. The primary goal of our study was to assess the long-term efficacy of GLP-1 RAs as add-on therapy to basal/bolus insulin regimens.

Methods: This study was a retrospective record review of all patients on basal/bolus insulin regimens who received additional therapy with a GLP-1 RA. The primary outcome was the change in glycosylated hemoglobin A _1c (HbA _1c ) at 3, 6, 12, 18, and 24 months after initiation of the GLP-1 RA. Secondary outcomes included change in weight and total daily dose (TDD) of insulin and incidence of hypoglycemia and other adverse effects (AEs).

Results: Ninety-two patient records were reviewed. Mean glycemic control changed from baseline −1.1% (95% CI, −1.3 to −0.8; P < .001) at 3 months; −1.0% (95% CI, −1.3 to −0.7; P < .001) at 6 months; −0.9% (95% CI, 1.3 to −0.6; P < .001) at 12 months; −0.9% (95% CI, −1.4 to −0.3; P = .002) at 18 months; and −0.7 (95% CI, −1.4 to 0.1; P = .07) at 24 months. A significant decrease in weight was also observed from baseline through 18 months, and a significant decrease in TDD of insulin was identified from baseline through 12 months. Hypoglycemia was documented in 29.8% of patients at any point during GLP-1 RA therapy, and gastrointestinal AEs were documented in 18.3% of patients.

Conclusions: Adding GLP-1 RAs to complex insulin regimens may help achieve glycemic control while decreasing insulin requirements and mitigating undesirable AEs, such as weight gain.