title: Combining a GLP-1 receptor agonist and basal insulin: study evidence and practical considerations.
abstract: Most patients with diabetes mellitus require multiple medications to achieve glycemic goals. Considering this and the increasing incidence of type 2 diabetes worldwide, the need for effective combination therapy is pressing. Basal insulin and glucagon-like peptide 1 (GLP-1) receptor agonists are frequently used to treat type 2 diabetes. Though both classes of medication are exclusively injectable, which may cause initial hesitation from providers, evidence for their combined use is substantial. This review summarizes the theoretical benefit, supporting evidence, and implementation of a combined basal insulin-GLP-1 receptor agonist regimen. Basal insulin added to a GLP-1 receptor agonist reduces hemoglobin A1c (HbA1c) without weight gain or significantly increased hypoglycemia. A GLP-1 receptor agonist added to basal insulin reduces HbA1c and body weight. Compared with the addition of meal-time insulin to basal insulin, a GLP-1 receptor agonist produces similar or greater reduction in HbA1c, weight loss instead of weight gain, and less hypoglycemia. Gastrointestinal adverse events are common with GLP-1 receptor agonists, especially during initiation and titration. However, combination with basal insulin is not expected to augment expected adverse events that come with using a GLP-1 receptor agonist. Basal insulin can be added to a GLP-1 receptor agonist with a slow titration to target goal fasting plasma glucose. In patients starting a GLP-1 receptor agonist, the dose of basal insulin should be decreased by 20 % in patients with an HbA1c ≤8 %. The evidence from 15 randomized prospective studies supports the combined use of a GLP-1 receptor agonist with basal insulin in a broad range of patients with uncontrolled type 2 diabetes.
authors.affiliation: Department of Pharmacotherapy and Translational Research, Department of Community Health and Family Medicine, Colleges of Pharmacy and Medicine, University of Florida, 1707 North Main Street, Gainesville, FL, 32609, USA, carris@ufl.edu.
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Carris
authors.forename: James R
authors.initials: JR
authors.lastname: Taylor
authors.forename: John G
authors.initials: JG
authors.lastname: Gums
mesh_terms: D001786:Blood Glucose; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism; D004359:Drug Therapy, Combination / Q000379:methods; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D000067757:Glucagon-Like Peptide-1 Receptor; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000009:adverse effects; D007267:Injections; D007328:Insulin / Q000008:administration & dosage / Q000009:adverse effects; D016032:Randomized Controlled Trials as Topic; D018027:Receptors, Glucagon / Q000819:agonists*; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D052216:Glucagon-Like Peptide 1; D000067757:Glucagon-Like Peptide-1 Receptor; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; D018027:Receptors, Glucagon; C000593833:GLP1R protein, human