Facts about kidneys

Below you can find out a range of useful facts and stats about kidneys. We endeavour to ensure these use the most up to date information but if you spot anything that is out of date, or think we should add something to this page, please let us know.

About the kidneys

• Most people have two kidneys – they lie under the ribs and above the waist (at the back), one on either side of the body.
• Kidneys are bean shaped and are around 10-12cm long (about the size of a clenched fist).
• Kidneys filter around 180 litres of blood every day, control the production of red blood cells and release hormones that regulate your blood pressure.
• Kidneys also produce urine, by removing waste products from the body.
• Kidneys help keep your bones strong and healthy by helping produce an active form of vitamin D.
• When your kidneys fail, harmful wastes build up in your body, your blood pressure may rise, and your body may retain excess fluid, leading to ankle swelling and shortness of breath (water in the lungs). When this happens, you need treatment to replace the work of your failed kidneys.
• Kidney disease is common, can affect anyone, and there is no cure.
• Kidney failure is fatal without dialysis or a transplant.

Kidney disease

• Around 3.5 million people in the UK have Chronic Kidney Disease (CKD).
• Uncontrolled diabetes and high blood pressure are the biggest causes of CKD.
• Right now, over 68,000 people in the UK are being treated for kidney failure (also known as stage 5 CKD, where kidney function is less than 15%).
• There are 40-45,000 premature deaths in the UK every year due to CKD (that's enough people to fill the Royal Albert Hall nine times over).
• Black, Asian and minority ethnic communities are five times more likely to develop CKD that other groups.
• Every day 20 people in the UK will develop kidney failure.
• There are around 1,000 children with CKD in the UK

Kidney transplantation and donation

• The first successful human kidney transplant was performed in 1954.
• Every day, over 10 people are added to the transplant list.
• For some people a kidney transplant may be the treatment option that allows them to live as much as they did before their kidneys failed. However, a kidney transplant is not a cure as it can only provide 50% of normal kidney function and requires recipients to take medicines for the rest of their lives.
• In the UK approximately 3,000 kidney transplants take place every year but around 5,000 people are still waiting.
• 8 out of 10 people on the transplant list are waiting for a kidney.
• The average wait for a transplant is about 2 and a half years (but this varies significantly throughout the UK).
• Every single day, two kidney patients will die in need of a transplant.
• Only 20% of those with kidney failure will be able to receive a transplant.

Acute Kidney Injury (AKI)

• Acute kidney injury (AKI) is a sudden drop in kidney function, often as a complication of another serious illness.
• AKI affects 1 in 5 people admitted to hospital as an emergency and may be more deadly than a heart attack.
• In the UK around 100,000 deaths each year are associated with AKI. That’s equivalent to ten people every hour. Research shows that 30% of these could be prevented with the right care and treatment.
• The costs to the NHS of AKI are estimated to be between £434 million and £620 million per year, which is more than the costs associated with breast cancer, or lung and skin cancer combined.
• The National Confidential Enquiry into Patient Outcome and Death (NCEPOD) found that only 50% of the patients who died from AKI had received 'good' care prior to their deaths.

Dialysis

• There are almost 30,000 people on dialysis in the UK.
• There are two different types of dialysis: haemodialysis and peritoneal dialysis. Haemodialysis is the most commonly used treatment:

Haemodialysis

• Haemodialysis means that your blood flows outside of your body and through a special filter that removes wastes and extra fluids, the clean blood is then returned to your body.
• The blood travels through tubes that are inserted into a fistula via needles. The fistula is prepared at least 8 weeks before starting haemodialysis via a small operation to re-route a vein in your arm to an artery, which increases blood flow. If patients have fragile veins then access can be made via a line, often placed near the neck or in the leg.
• Most people who have haemodialysis have it around 3 times a week for 3-5 hours at a time. This can be done in a hospital, a special unit or at home.
• Home haemodialysis allows more flexibility (for example having a session for 2 hours every day rather than longer sessions spaced out throughout the week), although patients need 4-12 weeks training beforehand.

Peritoneal dialysis

• The other type of dialysis is peritoneal dialysis. In peritoneal dialysis, a soft tube called a catheter is used to fill your abdomen with a cleansing liquid called ‘dialysis solution’. Your abdominal cavity is lined with a membrane (layer) called the peritoneum.
• The waste products and extra fluid (and salt) pass through the peritoneum from your blood into the dialysis solution, attracted by its high sugar (dextrose) content. They then leave your body when the dialysis solution is drained. This used solution is thrown away.
• The process of draining and filling is called an ‘exchange’ and takes about 30-40 minutes. The period the dialysis solution is in your abdomen is called the ‘dwell time’.
• Most people who have peritoneal dialysis will do four exchanges a day, each with a dwell time of 4-8 hours.
• There are two types of peritoneal dialysis - continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD).
• Continuous ambulatory peritoneal dialysis doesn’t require a machine and it is possible to walk around with the dialysis solution in your abdomen.
• Automated peritoneal dialysis requires a machine to fill and drain your abdomen; performing three to five exchanges during the night while you sleep; the process lasting 8-10 hours.

Mental health

• Up to one in three patients with kidney disease will experience depression at some point.
• None of the 84 units in the UK employs the recommended number of social workers for their kidney patient population, and only 5% employ the recommended number of psychologists for their patients.
• In renal paediatric care, over the last 15 years, psychology and social work services have decreased by 21%