There are several changes in the urine output of patients with chronic renal failure: 1. There is no significant reduction in the patient’s urine output: how much water is ingested, how much water can be excreted completely through the kidneys, and this is directly related to the primary renal disease. For example, polycystic kidney caused by renal damage, many patients will not have a significant decrease in urine output. Decreased urine output is often caused by the patient’s poor living habits, or improper treatment. For example, after the patient drinks a lot of water, dialysis, a lot of dehydration, repeated such a process, the patient’s urine volume will gradually decrease; 2, the patient’s urine gradually decreased: to reach the uremia stage, the patient’s urine volume gradually decreased, or even no urine at all, no urine at all, the patient, be sure to go to dialysis on a regular basis, to remove the excess water in the body; 3, the increase in nocturia: for the uremic patients who have urine, renal failure Patients, his urine will have a characteristic, often will appear night urine increase, why will appear night urine increase, because the renal failure patients of renal tubular concentration function deterioration, concentration function deterioration, night often will appear polyuria, so the appearance of nocturia is also a sign of kidney injury.