Chronic kidney disease (CKD) is a long-term condition where the kidneys do not work as well as normal.
CKD does not usually cause any symptoms until it has reached an advanced stage. It is usually detected at earlier stages by blood and urine tests. The main symptoms of advanced kidney disease include:
- swollen ankles, feet or hands (due to water retention)
- shortness of breath
- blood in the urine
The kidneys are two bean-shaped organs located on either side of the body, just underneath the ribcage. The main role of the kidneys is to filter out waste products from the blood before converting them into urine. The kidneys also:
- help maintain blood pressure
- maintain the correct levels of chemicals in your body which, in turn, will help the heart and muscles function properly
- produce a type of vitamin D that keeps bones healthy
- produce a substance called erythropoietin, which helps stimulate the production of red blood cells
How common is chronic kidney disease?
CKD is very common and is mainly associated with ageing. The older you get, the more likely you are to have some degree of kidney disease. It is estimated that about one in five men and one in four women between the ages of 65 and 74 has some degree of CKD.
The most common cause of CKD is damage caused by other chronic conditions, such as high blood pressure (hypertension) and diabetes.
CKD is more common in people of south Asian origin (those from India, Bangladesh, Sri Lanka and Pakistan) and black people than the general population. The reasons for this include higher rates of diabetes in south Asian people and higher rates of high blood pressure in African or Caribbean people.
CKD is a potentially serious condition. People with CKD are known to have an increased risk of a stroke or heart attack because of the changes that occur to the circulation.
In some people, CKD may cause kidney failure, which is also known as established renal failure (ERF) or end-stage kidney disease. In this situation, the usual functions of the kidney stop working. In order to survive, people with ERF may need to have artificial kidney treatment, called dialysis.
However, if the condition is diagnosed at an early stage, further damage to the kidneys can be prevented with a combination of lifestyle changes and medication. These changes can also reduce your risk of a stroke or heart attack. It is, therefore, very important to help yourself as much as you can.
Most people with CKD have no symptoms because the body can tolerate even a large reduction in kidney function. In other words, we are born with a lot more kidney function than is necessary for survival. Kidney function is often sufficient if only one kidney is working.
A change in kidney function is usually discovered through a routine blood or urine test. If you are diagnosed with kidney disease, your kidney function will be monitored with regular blood tests, and treatment aims to keep any symptoms to a minimum.
If the kidneys continue to lose function and there is progression towards kidney failure (established renal failure or ERF), this will usually be tracked by blood tests and monitoring. If kidney failure does occur, the symptoms may include:
- swollen ankles, feet or hands (due to water retention)
- shortness of breath
- blood or protein in your urine (protein in your urine is not something that you will notice as it can only be detected during a urine test)
- an increased need to urinate, particularly at night
- itchy skin
- erectile dysfunction in men (an inability to get or maintain an erection)
These are general symptoms and can be caused by many less serious conditions. Many of the symptoms above can be avoided if treatment begins at an early stage, before any symptoms appear.
High blood pressure (hypertension) and diabetes are the most common causes of kidney disease. The evidence indicates that high blood pressure causes just over a quarter of all cases of kidney failure. Diabetes has been established as the cause of around one-third of all cases.
High blood pressure
Blood pressure is a measure of the pressure your heart generates in your arteries with each pulse. Too much pressure can damage your body's organs, leading to heart disease, stroke and worsening of kidney function.
The cause of around 90% of cases of high blood pressure is unknown, although there appears to be a link between the condition and a person's general health, diet and lifestyle.
Known risk factors for high blood pressure include:
- age (the risk of developing high blood pressure increases as you get older)
- family history of high blood pressure (the condition seems to run in families)
- being of African-Caribbean or South Asian origin
- lack of exercise
- excessive alcohol consumption
- high amount of salt in your diet
- high-fat diet
Hypertension causes damage by putting strain on the small blood vessels in the kidneys. This prevents the filtering process from working properly.
Diabetes is a condition in which the body does not produce enough insulin (type 1 diabetes) or does not make effective use of insulin (type 2 diabetes). Insulin is needed to regulate the levels of glucose (sugar) in your blood, preventing the levels going too high after a meal and too low between meals.
If diabetes is poorly controlled, too much glucose can build up in your blood. The glucose can damage the tiny filters in the kidneys, which affects the ability of your kidneys to filter out waste products and fluids.
It is estimated that 20-40% of people with type 1 diabetes will develop kidney disease before they reach 50 years of age. Around 30% of people with type 2 diabetes also show signs of developing kidney damage.
The first sign of diabetic kidney disease is the appearance of low levels of protein in the urine. Therefore, your GP will ask for an annual urine test so that any kidney disease can be detected as early as possible.
Other causes of CKD include:
- glomerulonephritis (inflammation of the kidney)
- pyelonephritis (infection in the kidney)
- polycystic kidney disease (an inherited condition where both kidneys are larger than normal due to the gradual growth of masses of cysts)
- failure of normal kidney development in an unborn baby while developing in the womb
- systemic lupus erythematosus (a condition of the immune system where the body attacks the kidney as if it were foreign tissue)
- long-term, regular use of medicines, such as non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen
- blockages, for example due to kidney stones or prostate disease
If you are in a high-risk group for developing chronic kidney disease (CKD), it is important to be regularly screened for the condition. People who are not in a high-risk group are not normally screened for CKD.
Annual screening is recommended for the following groups:
- people with high blood pressure (hypertension)
- people with diabetes
- people who regularly take drugs which may damage the kidneys (nephrotoxic drugs), such as lithium, calcineurin inhibitors and long-term regular use of painkillers including ibuprofen (NSAIDs)
- people with cardiovascular disease (conditions that affect the heart, arteries and veins, such as coronary heart disease or stroke)
- people with structural renal tract disease, kidney stones or an enlarged prostate
- people with a family history of stage five CKD (see below for more information about staging) or an inherited kidney disease
- people with diseases that affect several parts of the body and may affect the kidneys, such as systemic lupus erythematosus
- people with blood in the urine (haematuria) or protein in the urine (proteinuria) where there is no known cause
Your GP can advise you about whether or not you should be screened for CKD.
Most often, the diagnosis of kidney disease is made because a routine blood or urine test indicates that the kidneys may not be functioning normally. If this happens, the test is usually repeated to confirm the diagnosis.
Glomerular filtration rate (GFR)
An effective way of assessing how well your kidneys are working is to calculate your glomerular filtration rate (GFR). GFR is a measurement of how many millilitres (ml) of waste fluid your kidneys can filter from the blood in a minute (measured in ml/min). A healthy pair of kidneys should be able to filter more than 90ml/min.
It is difficult to measure the GFR directly, so it is estimated using a formula. The result is called the estimated GFR or eGFR. Calculating your eGFR involves taking a blood sample and measuring the levels of a waste product called creatinine and taking into account your age, gender and ethnic group. The result is similar to the percentage of normal kidney function. For example, an eGFR of 50ml/min equates to 50% kidney function.
A five-stage system, based on eGFR levels, is used to describe the progression of CKD. The higher the stage, the more severe the CKD. The five stages are described below.
- Stage one: the eGFR is normal (over 90), but other testing shows evidence of kidney damage.
- Stage two: the eGFR has decreased slightly (60-89), and there is other evidence of kidney damage.
If you have stage one or two CKD, it is recommended that you have annual eGFR tests so that the progression of the condition can be carefully monitored.
- Stage three (divided into stage 3a and 3b). In stage 3a, the eGFR has decreased mildly (45-59) and in stage 3b it has decreased moderately (30-44). Further testing should be carried out every six months.
- Stage four: the eGFR has decreased severely (15-29). By this time, it is possible that you will be experiencing symptoms of CKD. Further testing should be carried out every three months.
- Stage five: the kidneys have lost almost all of their function (an eGFR of below 15), which is known as established renal failure. Further testing should be carried out every six weeks.
However, over time, GFR can fluctuate, so one abnormal test result does not automatically mean that you have CKD. A diagnosis of CKD is usually only confirmed if repeated eGFR tests show that your eGFR is consistently lower than normal over three months.
A number of other tests are also used to assess the levels of damage to your kidneys. These are outlined below.
- Urine tests are used to see whether there is blood or protein in your urine. The results of some urine tests can be given immediately, but other tests have to be sent to the laboratories.
- Kidney scans, such as an ultrasound scan, MRI scan or CT scan, can be used to find out whether there are any unusual blockages in your urine flow. In cases of advanced kidney disease, the kidneys are shrunken and have an uneven shape.
- A kidney biopsy is when a small sample of kidney tissue is taken so that the cells can be examined under a microscope for damage.
Your treatment will depend on the stage of your chronic kidney disease (CKD). Stages one, two and three CKD can usually be treated by your GP.
Treatment involves making changes to your lifestyle and, in some cases, taking medication to control your blood pressure and lower your blood cholesterol levels. This should help prevent any further damage to your kidneys and circulation.
If you have stage four or stage five CKD, you will usually be referred to a specialist. In addition to the treatments above, you may also be given a number of different medications to control or prevent the symptoms of CKD.
Kidney failure, also called established renal failure or ERF, occurs when you have lost nearly all your kidney function and the condition has become life threatening. About 1% of people with stage three CKD develop ERF.
If you have kidney failure, you will need to decide on the next stage of treatment. Your choice will be whether to have treatment with dialysis (a means of artificially replacing some functions of the kidney), a kidney transplant, or other treatment options that involve less intervention, also known as supportive care.
The following lifestyle changes are known to help reduce your blood pressure and control CKD:
- stopping smoking
- eating a healthy, low-fat, balanced diet
- restricting your salt intake to less than 6g (0.2oz) a day
- not using over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, except when advised to by a medical professional
- moderating your alcohol intake so that it is within recommended limits (no more than 21 standard drinks a week for men and 14 for women)
- losing weight if you are overweight or obese
- doing regular exercise for at least 30 minutes a day, five times a week
Medications for high blood pressure
One of the most important ways to reduce the progression of kidney damage is to manage high blood pressure. Good control of blood pressure is vital to protect the kidneys. If losing weight, reducing your salt intake and making other lifestyle changes do not control your blood pressure, medication may be needed.
There are many types of blood pressure drug. Medicines called angiotensin converting enzyme (ACE) inhibitors are especially used to control high blood pressure in people with CKD.
As well as reducing blood pressure around the body and reducing the strain on blood vessels, ACE inhibitors give additional protection to the kidney.
ACE inhibitors include:
Side effects of ACE inhibitors include:
- a persistent, dry cough
- tiredness or weakness
Most of these side effects should pass within a few days, although some people continue to have a dry cough.
If the side effects of ACE inhibitors are particularly troublesome, you can be given an alternative medication called an angiotensin-II receptor blocker (ARB). This group of medicines includes candesartan, eprosartan, irbesartan and losartan. The side effects of ARBs are uncommon, but can include dizziness.
Both ACE inhibitors and ARBs can cause a reduction in kidney function and increased levels of potassium in the blood, so blood tests will need to be performed after you start treatment and whenever the dose changes.
Aspirin or statins
Studies have shown that people with CKD have a higher risk of cardiovascular disease, including heart attacks and strokes. This is because some of the risk factors for CKD are the same as those for heart attacks and strokes, including high blood pressure and high levels of cholesterol in the blood (atherosclerosis).
To help reduce your risk of having a heart attack or stroke, you may be given low-dose aspirin or statins.
Statins are a type of medication used to lower cholesterol levels. Cholesterol causes narrowing of the arteries that can lead to blockage of the blood supply to the heart (causing a heart attack) or the brain (causing a stroke). Statins work by blocking the effects of an enzyme in your liver (called HMG-CoA reductase), which is used to make cholesterol.
Statins sometimes have mild side effects, including:
- abdominal pain
Occasionally, statins can cause muscle pain, weakness and tenderness. If you experience any of these symptoms, contact your GP. You may need to have a blood test or change your treatment.
Oedema (fluid retention)
If you have kidney disease, you may be asked to reduce your daily fluid and salt intake. You may develop a build-up of fluid as your kidneys will not be able to get rid of fluid as well as they did before. If you are asked to reduce the amount of fluid you drink, you must also take into account fluid in foods, such as soup and yoghurt. Your GP or dietitian can advise you about this.
The excess fluid that occurs as a result of kidney disease often builds up in your ankles or around your lungs. You may also be given diuretics (water tablets), such as furosemide, which will help get rid of the excess fluid from your body.
If you do not have any fluid retention and you have not been told to reduce your fluid intake, there is no need to do so. In fact, it could be harmful in some circumstances.
Many people with stage three, four and five CKD develop anaemia. Anaemia is a condition in which you do not have enough red blood cells. Symptoms of anaemia include:
- shortness of breath (dyspnoea)
- palpitations (awareness of heartbeat)
Anaemia can occur because of many other conditions and your doctor will investigate to rule out any other possible causes.
Most people with kidney disease will be given iron supplements because iron is needed for the production of red blood cells. To boost iron levels, iron may be given as tablets, such as daily ferrous sulphate tablets, or as occasional intravenous injections.
If this is not enough to treat anaemia, you may given an injection of erythropoietin, a hormone which helps your body produce more red blood cells. These injections are often administered intravenously (into a vein) or subcutaneously (under the skin). Examples of these injections include epoetin alfa, beta and zeta, darbepoetin and methoxy polyethylene glycol-epoetin beta.
Correction of phosphate balance
If you have stage four or five kidney disease, you can get a build-up of phosphate in your body because your kidneys cannot get rid of it. Phosphate is a mineral that, with calcium, makes up most of your bones. Phosphate is obtained through diet, mainly dairy foods. The kidneys usually filter out any excess phosphate. If phosphate levels rise too much, it can upset the normal calcium balance of the body. This can lead to thinning of the bones and furring of the arteries.
You may be asked to limit the amount of phosphate in your diet. Foods that are high in phosphate include red meat, dairy produce, eggs and fish. Your GP or dietitian should be able to advise you about how much phosphate you can eat. However, there is no advantage in reducing your intake of these foods unless you have a raised phosphate level. Always ask a healthcare professional before changing your diet.
If reducing the amount of phosphate in your diet does not lower your phosphate level enough, you may be given medicines called phosphate binders. These medicines bind to the phosphate in the food inside your stomach and stop it from being absorbed into your body.
To work properly, phosphate binders must be taken just before meals. The most commonly used phosphate binders are calcium carbonate and (less commonly) aluminium hydroxide.
The side effects of phosphate binders are uncommon but include:
- stomach ache
- flatulence (wind)
- skin rash
- itchy skin
Vitamin D supplements
People with kidney disease can have low levels of vitamin D, which is needed for healthy bones. This is because the kidneys need to activate the vitamin D from food and from the sun before it can be used by the body.
You may be given a vitamin D supplement called alfacalcidol or calcitriol to help boost vitamin D levels and reduce the risk of bone damage.
Treatment for kidney failure - dialysis or transplant
Many people with kidney failure can continue with treatment using medicines and will have good-functioning kidneys for the rest of their lives.
In a few people, kidney disease will progress to the stage where the kidneys stop working and it becomes life threatening. This is called kidney failure or established renal failure (ERF).
This rarely happens suddenly, and there will be time to plan the next stage of your condition. The decision whether to have dialysis, a kidney transplant or supportive treatment should be discussed with your healthcare team.
If you decide not to have dialysis or a transplant for kidney failure, or they are not suitable for you, you will be offered supportive treatment. This is also called palliative care. The aim is to treat and control the symptoms of kidney failure without using dialysis or transplantation. Supportive treatment includes medical, psychological and practical care for both the person with kidney failure and their family, including discussion about how you feel and planning for the end of life.
Many people choose supportive treatment because they:
- do not want to go through the inconvenience of treatment with dialysis or transplantation
- are advised against dialysis because they have other serious illnesses that will shorten their life, and the negative aspects of treatment outweigh any likely benefits
- have been on dialysis but have decided to stop this treatment
- are being treated with dialysis, but have another serious physical illness, especially severe heart disease, that will shorten their life
If you choose to have supportive treatment, your kidney unit will still look after you.
Doctors and nurses will make sure you receive:
- medicines to protect your remaining kidney function for as long as possible
- medicines to treat other symptoms of kidney failure, such as feeling out of breath, anaemia, loss of appetite or itchy skin
- help to plan your home and money affairs
- bereavement support for your family after your death
Managing your condition
If you have a chronic (long-term) condition, such as diabetes, that could potentially cause chronic kidney disease, it is important that it is carefully managed.
Follow the advice of your GP and keep all appointments relating to your condition. People with diabetes are advised to have their kidney function tested every year.
Smoking increases your risk of cardiovascular disease, including heart attacks or strokes, and it can increase the likelihood that any existing kidney problems will get worse.
If you stop smoking, you will improve your general health and reduce your risk of developing other serious conditions, such as lung cancer and heart disease.
A healthy diet is important for preventing chronic kidney disease (CKD). It will lower the amount of cholesterol in your blood and keep your blood pressure at a healthy level. Eat a balanced diet that includes plenty of fresh fruit and vegetables (five portions a day) and whole grains.
Limit the amount of salt in your diet to no more than 6g (0.2oz) a day. Too much salt will increase your blood pressure. One teaspoonful of salt is equal to about 6g.
Avoid eating foods that are high in saturated fat because this will increase your cholesterol level.
Foods that are high in saturated fat include:
- meat pies
- sausages and fatty cuts of meat
- ghee (a type of butter often used in Indian cooking)
- hard cheese
- cakes and biscuits
- foods that contain coconut oil or palm oil
Eating some foods that are high in unsaturated fat can help decrease your cholesterol level. Foods that are high in unsaturated fat include:
- oily fish
- nuts and seeds
- sunflower oil
- rapeseed oil
- olive oil
Drinking excessive amounts of alcohol will cause your blood pressure to rise, as well as raising the cholesterol levels in your blood. Therefore, sticking to the recommended alcohol consumption limits is the best way to reduce your risk of developing high blood pressure (hypertension) and CKD.
The recommended limits for alcohol are:
- 21 standard drinks of alcohol a week for men
- 14 standard drinks of alcohol a week for women
A standard drink of alcohol is equal to about half a pint of normal strength beer, a small glass of wine or a pub measure of spirits. For more information,
Regular exercise should help lower your blood pressure and reduce your risk of developing CKD.
At least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity (i.e. cycling or fast walking) every week, is recommended.
Relationships and support
Coming to terms with a condition such as kidney disease can put a strain on you, your family and your friends. It can be difficult to talk to people about your condition, even if they are close to you.
Learning about kidney disease often helps because you and your family will understand more about what to expect and feel more in control of the illness, instead of feeling that your lives are now dominated by kidney disease and its treatment.
Be open about how you feel, and let your family and friends know what they can do to help. However, do not feel shy about telling them that you need some time to yourself, if that is what you need.
Your GP or nurse can reassure you if you have questions about your kidney disease, or you may find it helpful to talk to a trained counsellor, psychologist or specialist telephone helpline operator. Your GP surgery will have information on these.
Some people find it helpful to talk to other people with kidney disease at a local support group or through an internet chat room.
Sex and pregnancy
The symptoms of kidney disease and the stress it causes in your life can affect your sexual relationship.
Some couples become closer after a diagnosis of kidney disease, while others find that their loved ones are affected by worries about how they will cope with the effects of the illness. Both men and women may experience issues about body image and self-esteem, and this can affect the relationship.
Try to share your feelings with your partner. If you have problems with sex that do not get better with time, you can speak to a counsellor or sex therapist.
People on dialysis often experience specific sexual difficulties. Loss of sex drive in both men and women and impotence in men are commonly reported problems. Treatment is available. However, it may take some time and requires commitment from both partners. The first step is to discuss it with your healthcare team.
Both men and women with early stage kidney disease will find that their fertility is unaffected. This means it is important to use contraception unless you want to have a baby.
Later stage kidney disease may affect women's periods, which can make pregnancy more difficult. For men, later stage kidney disease can cause a reduction in sperm count. However, having kidney disease does not mean you will not get pregnant or be able to father a child, so both men and women need to use an effective method of contraception unless they want to have a baby.
Women who want to have a baby should talk to their renal specialist or an obstetrician with an interest in kidney disease. Depending on the stage of kidney disease, there can be risks to both the mother and the baby. It is important to minimise any risk with a planned pregnancy. Your healthcare team can advise you about this.
About 1% of people with stage three CKD develop kidney failure, also called established renal failure or ERF. Kidney failure has a major impact on your life and the lives of those close to you. People diagnosed with kidney failure usually go through shock, grief and denial before they accept their condition.
Choices if you have established renal failure
If you have established renal failure (ERF), you will need to decide whether to have treatment with dialysis (a machine that replicates the functions of the kidneys) or a kidney transplant. You may decide to have neither treatment and to have supportive care. These choices should be made with your healthcare team.
For people who want active treatment for their ERF, a transplant would be the best option. However, a transplant is only suitable for about half of all people with ERF. This is because they may have had recent cancer or they are not physically fit.
Many people who have slowly progressive kidney failure and who have very serious health problems, and who are usually older, may choose to avoid dialysis. Supportive care can still allow you to live for some time with a good quality of life.
Dialysis can take place at home or in hospital. It involves filtering the blood of waste products and excess water. It is not as efficient as a human kidney, so people with kidney failure usually need to restrict their intake of fluid and certain foods. They also require additional medicines such as iron supplements, phosphate binders and antihypertensive medicine (to reduce blood pressure). There are two types of dialysis: peritoneal dialysis and haemodialysis.
The abdomen (tummy) has a lining called the peritoneal membrane, which can be used as a filter to remove excess waste and water. If you have opted for peritoneal dialysis, a tube (catheter) will be inserted into your abdomen during an operation. This will allow you to drain dialysis fluid in and out of your tummy yourself. You will not need to go into hospital to be treated, but you will have to spend an hour or two each day draining the fluid. The treatment involves either four exchanges spaced out during the day, each taking half an hour, or attaching yourself to a machine overnight that pumps the fluid in and out for you.
Haemodialysis removes waste products and excess fluid that build up in the body when the kidneys stop working. Blood is taken from the body to be cleaned in a filter known as a dialyser. It is effectively an artificial kidney.
The whole process takes about four hours and usually has to be repeated three times a week. Most people go into hospital to have haemodialysis. However, some people choose to have the treatment in their own home.
Home haemodialysis will give you more flexibility, but comes with greater responsibility. You'll need to have the space in your home for a dedicated machine and, in most cases, a lot of support from a close family member or friend. Some people choose to have their dialysis at night while they are asleep, others during the day. Most people who choose home haemodialysis have it every day, so their fluid intake is not as restricted.
Quality vascular access
During haemodialysis, it is important that large volumes of blood are passed through the machine. This requires special measures to get into large enough blood vessels. For this reason, haemodialysis patients need a minor operation to join one of the deep arteries to a superficial vein (called a fistula). This is carried out in day surgery and should be done at least six weeks before dialysis is required because it needs time to mature before it can be used. Occasionally, there will be insufficient time for a fistula to be created before dialysis is required. In this case, a temporary solution is found, usually involving the use of an indwelling plastic dialysis catheter.
All the issues will be discussed in detail with you by the dialysis team before any decisions are made.
A kidney transplant, when suitable, is the best treatment for ERF. The transplanted kidney can be obtained from a deceased or living donor and survival rates are now extremely good. About 90% of transplants still function after five years and many transplants work usefully after 20 years. The main reason people have to wait for a transplant is the shortage of available donors.
One major risk after transplantation is rejection, where the immune system attacks the donated kidney because it mistakes it for a foreign object. This is prevented with the use of strong drugs to suppress the immune system. These drugs need to be taken meticulously. They are usually well tolerated but may have side effects, including an increased susceptibility to infections and some forms of cancer. For this reason, transplant patients are given regular reviews in a specialist transplant clinic.