DPP4 and heart failure: SGLT-2: sodium-glucose cotransporter-2; oGLDs: oral glucose-lowering drugs (e.g. metformin, sulfonylureas, dipeptidyl peptidase-4 inhibitors); thiazolidinediones: glucagon-like peptide-1 receptor agonists; MACE (major adverse cardiovascular events): defined as the composite of nonfatal myocardial infarction, nonfatal stroke, and cardiovascular mortality); T2DM: type-2 diabetes mellitus; HHF: hospitalization for heart failure; MI: myocardial infarction; ADAs: antidiabetic drug classes