According to cardiovascular outcome trials, some anti-diabetic drugs can improve cardiovascular outcomes in patients with type 2 diabetes. Sodium glucose cotransporter 2 inhibitors (empagliflozin, canagliflozin, and dapagliflozin) have a strong preventive effect on both hospitalization for heart failure and the decline in kidney function in patients with type 2 diabetes, while glucagon-like peptide-1 receptor agonists, especially human glucagon-like peptide-1 receptor agonists (liraglutide, semaglutide, and albiglutide), suppress arteriosclerotic diseases (stroke and myocardial infarction). Using these medications in combination could possibly prevent both hospitalization for heart failure and arteriosclerotic events. Dipeptidyl peptidase 4 (DPP-4) inhibitors are preferentially used as add-on therapy for type 2 diabetes. Cardiovascular outcome trials conducted so far suggest that DPP-4 inhibitors (sitagliptin, alogliptin, and saxagliptin) do not promote arteriosclerotic disease, but there may be a difference between these drugs with regard to safety for heart failure. Previous cardiovascular outcome trials have mainly focused on type 2 diabetes patients with established cardiovascular disease. In contrast, the CARMELINA study investigated the cardiovascular safety of linagliptin, a DPP-4 inhibitor, in patients with type 2 diabetes and kidney dysfunction.