Chronic renal failure, also known as chronic renal insufficiency, refers to a syndrome of chronic progressive renal parenchymal damage caused by various kidney diseases or accumulated kidney systemic diseases, which makes the kidney unable to maintain its basic functions, such as excreting metabolic waste, regulating water-salt and acid-base balance, secreting and regulating various hormone metabolism, etc., thus presenting a series of clinical symptoms such as azotemia, metabolic disorders and involvement of various systems. Chronic renal failure is one of the common diseases of the urinary system in the elderly. As kidney lesions continue to develop, renal function may progressively decline, and chronic renal failure is an irreversible damage.