The kidneys remove waste products from the blood. If a person is affected by chronic kidney disease (CKD), they retain less than 40% of their kidney function, as the kidney filters are damaged. This can be caused by, amongst other things, inflammation in the kidneys, diabetes, high blood pressure and hardening of the arteries. Symptoms of CKD may include tiredness, general malaise, cramps and itching. People with CKD are also at an increased risk of cardiovascular diseases.