Chronic kidney disease occurs when damage to the kidneys causes reduced kidney function. Kidney disease has usually been present for many years and may slowly get worse over time.

Chronic kidney disease can be mild, moderate, or severe.

• Mild to moderate chronic kidney disease may not cause symptoms. The kidneys are usually able to adapt and function well enough so that noticeable symptoms of kidney failure do not occur.
• Severe chronic kidney disease causes noticeable symptoms, such as electrolyte imbalances and fluid buildup (edema). Many people who have severe chronic kidney disease will eventually develop kidney failure and will require dialysis.