DPP4 and diabetes mellitus: While metformin has been the preferred agent for the treatment of diabetes in this population due to its favorable effects on the metabolic syndrome [45], newer diabetes treatments include dipeptidyl peptidase-4 inhibitors (DPP-4Is), glucagon-like peptide-1 receptor agonists (GLP-1RAs), and sodium-glucose cotransporter 2 inhibitors (SGLT-2Is; Figure 3).