REN and Hypertension: In patients with MHD, both traditional risk factors of HFpEF including hypertension and diabetes as well as non-traditional risk factors, such as reduced renal function, increased volume load, the renin–angiotensin–aldosterone system (RAAS) activation, anemia, calcium, and phosphate metabolism disorders, and arteriovenous fistulas can also contribute to cardiac hypertrophy and ventricular remodeling (24).