People with CKD have compromised kidney function. This can be from a number of causes. Some are born with it, others suffer kidney damage, while others have a gradual loss of kidney function over time. As time goes by the kidneys become less effective at filtering waste products from blood; water, waste and toxic substances therefore accumulate in the body. A minority of people with CKD suffer complete kidney failure, and require renal replacement therapy (RRT): dialysis or transplant. People with CKD are also at increased risk of stroke, heart attack, bone disease and other conditions.