Creatinine 400umol/L is mostly caused by pathological factors, clinically, we should firstly clarify the cause of the disease, first of all, we should distinguish whether it is caused by acute renal failure or chronic renal disease, acute renal failure treatment in time usually does not affect the life expectancy, but may affect the life expectancy if it is not actively treated. Some patients with chronic kidney disease can survive after dialysis treatment, if not standardized treatment may also affect life expectancy. Acute renal failure is categorized into pre-renal, renal and post-renal. If it is pre-renal such as circulating blood volume insufficiency, post-renal such as stones, tumors, etc., creatinine may drop after rehydration and removal of obstruction, and timely treatment usually does not affect life expectancy. If the disease is renal, such as drug-induced, it may be improved after stopping related drugs and symptomatic supportive treatment. If the disease becomes chronic, some patients can survive for a long time after regular dialysis, but if it is not actively treated, it may affect the life expectancy. If the creatinine is elevated due to chronic kidney disease, the survival time of the patients will be significantly shortened if they cannot be treated actively. If medication is ineffective, patients with obvious symptoms can be treated with regular dialysis to remove toxic substances and excess water from the body and ensure the stability of vital signs, and most of the patients can survive for a long time through dialysis. Patients with elevated creatinine levels should go to the hospital in a timely manner, under the guidance of a physician to clarify the cause of the disease, assess the severity of the disease, and formulate specific treatment methods.