REN and atrial fibrillation: Abbreviations: AF = atrial fibrillation, CKD = chronic kidney disease, DKA = diabetic ketoacidosis, HF = heart failure, RAAS = renin–angiotensin–aldosterone system, T2DM = type 2 diabetes mellitus, UTI = urinary tract infection, SGLT-2 = sodium-glucose cotransporter-2.