Chronic kidney disease (CKD) is a condition in which the kidneys are not working properly. It is caused by damage to tiny structures within the kidneys called nephrons. In the early stages, CKD does not cause problems. As a result, most people don’t know they have a problem.

The kidneys are bean-shaped organs in the lower back just below the rib cage. Each one is about the size of a fist. The two kidneys filter wastes from the blood and make urine. They also catch needed substances and return them to the bloodstream. If the kidneys don’t work well, wastes build up in the blood. The kidneys also keep the balance of water in the body. They release hormones that keep the bones strong, control blood pressure, and help the body make red blood cells. If your kidneys stop working, your bones may become weak, your blood pressure may go up, and your red blood cell count may drop.

Anatomy of the Kidneys
Anatomy of the Kidney
Copyright © Nucleus Medical Media, Inc.


CKD is a progressive condition. Doctors use stages to describe how serious it is. The stage is based on the glomerular filtration rate (GFR).

Stage Glomerular Filtration Rate (GFR)
1 Over 90 mL/min (normal)
2 60 to 89 mL/min (mild decrease)
3 30 to 59 mL/min (moderate decrease)
4 15 to 29 mL/min (severe decrease)
5 under 15 mL/min (kidney failure or end-stage renal disease)


The two most common causes of CKD are diabetes and high blood pressure.

  • Diabetes type 1 and type 2 occur when the body doesn’t process the sugar in the blood well. The amount of sugar in the blood increases. High blood glucose damages the kidneys, the heart, blood vessels, and eyes.
  • High blood pressure occurs when there is high pressure within the arteries of the body. High blood pressure damages the kidneys.

Other conditions that can cause CKD include:

Revision Information

  • Reviewer: EBSCO Medical Review Board Adrienne Carmack, MD
  • Review Date: 05/2018 -
  • Update Date: 06/15/2018 -