Within 12 months of patients receiving a GLP-1 agonist, the mean HbA1c reduction was 1.1%, which is comparable to other GLP-1 agonist clinical trials. For semaglutide 0.5 mg and 1.0 mg dosages, the mean HbA1c reduction was 1.4% and 1.6%, respectively.9 For dulaglutide 0.75 mg and 1.5 mg dosages, the mean HbA1c reduction ranged from 0.7% to 1.6% and 0.8% to 1.6%, respectively.10 For liraglutide 1.8 mg dosage, the mean HbA1c reduction ranged from 1.0% to 1.5%.11 The mean weight loss in this study was 13.9 lb. Along with HbA1c, weight loss in this review was comparable to other GLP-1 agonist clinical trials. Patients administering semaglutide lost up to 14 lb, patients taking dulaglutide lost up to 10.1 lb, and patients on liraglutide lost on average 6.2 lb.9-11 Even with medications such as insulin and sulfonylurea that have the side effects of hypoglycemia and weight gain, adding a GLP-1 agonist showed a reduction in HbA1c and weight loss relatively similar to previous clinical trials.
A study on the effects of adding semaglutide to insulin regimens in March 2023 by Meyer and colleagues displayed similar results to this retrospective chart review. That study concluded that there was blood glucose improvement (HbA1c reduction of 1.3%) in patients after 6 months despite a decrease in the insulin dose. Also, patients lost a mean weight of 11 lb during the 6-month trial.3 This retrospective chart review at the WBVAMC adds to the body of research that supports potential reductions or discontinuations of insulin and/or sulfonylureas with the addition of a GLP-1 agonist.
Limitations
Several limitations of this study should be considered when evaluating the results. This review was comprised of a mostly older, male population, which results in a low generalizability to organizations other than VA medical centers. In addition, this study only evaluated patients on a GLP-1 agonist followed in a pharmacist-led PACT clinic. This study excluded patients who were prescribed a GLP-1 agonist by an endocrinologist or a pharmacist at one of the community-based outpatient clinics affiliated with WBVAMC, or a pharmacist or clinician outside the VA. The sole focus of this study was patients in a pharmacist-led VAMC clinic. Not all patient data may have been included in the study. If a patient did not have an appointment at baseline, 3, 6, and 12 months or did not obtain laboratory tests, HbA1c and weights were not recorded. Data were collected during the COVID-19 pandemic and in-person appointments were potentially switched to phone or video appointments. There were many instances during this chart review where a weight was not recorded at each time interval. Also, this study did not consider any other diabetes medications the patient was taking. There were many instances where the patient was taking metformin and/or sodium-glucose cotransporter-2 (SGLT-2) inhibitors. These medications along with diet could have affected the weight results as metformin is weight neutral and SGLT-2 inhibitors promote weight loss.15 Lastly, this study did not evaluate the amount of insulin reduced, only if there was a dose reduction or discontinuation of insulin and/or a sulfonylurea.
Conclusions
Dose reductions and a discontinuation of insulin or a sulfonylurea with the addition of a GLP-1 agonist may be needed. Patients on both insulin and a sulfonylurea may need closer monitoring due to the higher incidences of discontinuations compared with patients on just 1 of these agents. Dose reductions or discontinuations of these diabetic agents can promote positive patient outcomes, such as preventing hypoglycemia, minimizing weight gain, increasing weight loss, and reducing HbA1c levels.
Acknowledgments
This material is the result of work supported with resources and the use of facilities at the Wilkes-Barre Veterans Affairs Medical Center in Pennsylvania.