DPP4 and diabetes mellitus: Of the 124,718 papers published in the field of diabetes in the last 10 years, 3890 (3%) were meta-analyses [6], with more than 100 on dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists and/or sodium–glucose cotransporter 2 (SGLT-2) inhibitors [7–9].