DPP4 and Alzheimer disease: Of the 103,789 patients who received monotherapy (excluding patients receiving AD intracombination, insulin plus AD combination and insulin therapy), most were treated with dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors; 56.8%), followed by metformin (15.4%), sulfonylurea (SU; 10.7%), alpha-glucosidase inhibitors (alpha-GI; 9.1%), thiazolidinediones (3.4%), glinides (2.8%), sodium glucose co-transporter-2 inhibitors (SGLT2i; 1.1%) and glucagon like peptide-1 receptor agonists (0.8%) (Fig. 3).