DPP4 and peripheral arterial disease: BMI:  Body Mass Index; BSA:  Body Surface Area; PAD: peripheral arterial disease; COPD: Chronic obstructive pulmonary disease; CKD: Chronic kidney disease with 30 < GFR < 60 ml/min; PCI:  Percutaneous Coronary Intervention; AF: Atrial fibrillation; RAAS-I: Renin-angiotensin-aldosterone system inhibitors; CCB: Calcium Channel Blockers; DPP-4: DipeptidylPeptidase 4; GLP-1: Glucagon-like peptide-1