Chronic Kidney Disease: The Complete Guide to Stages, Treatment, Diet and Living Well

Around one in ten adults worldwide has chronic kidney disease, and most of them do not know it. Caught early, kidney disease can often be slowed for years. This guide explains what is happening, what you can do and what choices lie ahead.

Imagine a letter after a routine diabetes check: “Your kidney function is reduced, stage 3a.” You feel completely well, so you put it in a drawer. Understanding what it means, and acting on it, could protect your kidneys and your heart for decades.

What your kidneys do

Your two kidneys, each about the size of a fist, filter around 180 litres of blood every day. They remove waste products and extra fluid as urine, balance salts and minerals such as sodium, potassium and phosphate, help control blood pressure, make a hormone that stimulates red blood cell production, and activate vitamin D to keep bones healthy.,When the kidneys are damaged, all of these functions can be affected, often slowly and silently.

What chronic kidney disease is

Chronic kidney disease (CKD) means the kidneys have been damaged or have reduced function for at least three months. It is diagnosed by blood tests showing a low estimated glomerular filtration rate (eGFR), urine tests showing protein (albumin) leaking into the urine, or other signs of kidney damage on scans or tests.,CKD is very different from acute kidney injury, which is a sudden drop in kidney function over hours or days, often during illness, and can often recover. However, repeated episodes of acute kidney injury can lead to CKD.

Common causes

• Diabetes, the leading cause in many countries
• High blood pressure
• Glomerulonephritis and other kidney inflammation
• Polycystic kidney disease, an inherited condition
• Repeated kidney infections or blockages, such as from kidney stones or an enlarged prostate
• Long-term use of some medicines, including anti-inflammatory painkillers and lithium
• Heart disease
• Sickle cell disease and HIV in some populations
• In some regions, CKD of unknown cause affects agricultural workers, possibly linked to heat stress and dehydration

Who should be tested

Testing is recommended for people at higher risk, including those with diabetes, high blood pressure, heart disease, a family history of kidney failure, a past episode of acute kidney injury, kidney stones, or long-term use of medicines that affect the kidneys. People of African, Caribbean and South Asian descent have a higher risk of kidney failure. Testing usually involves an eGFR blood test and a urine ACR test.

Stages of CKD

• G1: eGFR 90 or more, with other signs of kidney damage
• G2: eGFR 60 to 89, with other signs of kidney damage
• G3a: eGFR 45 to 59
• G3b: eGFR 30 to 44
• G4: eGFR 15 to 29
• G5: eGFR below 15, also called kidney failure
• Albuminuria is graded A1 (normal to mildly increased), A2 (moderately increased) and A3 (severely increased)

Why the urine test matters

Protein in the urine is not just a marker of kidney damage; it also predicts how quickly kidney disease is likely to progress and the risk of heart disease. Two people with the same eGFR can have very different outlooks depending on their ACR. That is why both tests should be done regularly, and why treatments that reduce protein in the urine are so valuable.

Symptoms

Most people with CKD stages 1 to 3 have no symptoms. Symptoms usually appear only when kidney function is much reduced, often in stage 4 or 5.,These may include tiredness, swollen ankles, feet or hands, shortness of breath, itchy skin, muscle cramps, poor appetite, nausea, difficulty sleeping, needing to pass urine more at night, and difficulty concentrating. Because these symptoms are common and non-specific, blood and urine tests are the only reliable way to find CKD early.

Slowing kidney disease: blood pressure

Controlling blood pressure is one of the most important ways to protect the kidneys. Targets are often lower for people with CKD, especially if there is protein in the urine. Your healthcare provider will set a target suited to you.,ACE inhibitors (such as ramipril) and angiotensin receptor blockers (such as losartan) are often preferred because they lower blood pressure and reduce protein leaking into the urine. A small rise in creatinine after starting is expected; your kidney function and potassium will be checked within a couple of weeks.

Slowing kidney disease: newer medicines

SGLT2 inhibitors, such as dapagliflozin and empagliflozin, have been shown in large trials to slow the progression of CKD and reduce the risk of kidney failure, heart failure and death, both in people with and without diabetes. Many guidelines now recommend them for a large proportion of people with CKD.,For people with type 2 diabetes and CKD with protein in the urine, finerenone, a newer type of medicine, may be added to further reduce kidney and heart risks. GLP-1 receptor agonists such as semaglutide have also shown kidney benefits in people with type 2 diabetes.

Protecting your heart

People with CKD are more likely to die from heart disease than to need dialysis. A statin is often recommended to reduce cholesterol and heart risk. Not smoking, staying active, controlling blood pressure and blood sugar, and keeping a healthy weight protect both the heart and the kidneys.

Diabetes and CKD

If you have diabetes, keeping blood sugar within your target range slows kidney damage. Some diabetes medicines need dose changes or should be avoided as kidney function falls, including metformin at lower eGFR levels and some sulfonylureas. Others, such as SGLT2 inhibitors and GLP-1 receptor agonists, may be chosen because they protect the kidneys. Your medicines should be reviewed whenever your eGFR changes.

Medicines to be careful with

• Anti-inflammatory painkillers such as ibuprofen, naproxen and diclofenac, which can harm the kidneys
• Some antibiotics and antivirals, which need dose adjustment
• Contrast dye for some scans, which may need precautions
• Herbal remedies and supplements, some of which are harmful to the kidneys
• Always tell healthcare providers and pharmacists that you have CKD before starting any medicine

Sick day rules

If you become unwell with vomiting, diarrhoea or fever and cannot keep fluids down, your kidneys are at risk of acute injury. Some medicines increase that risk when you are dehydrated, including ACE inhibitors, ARBs, diuretics, metformin, SGLT2 inhibitors and anti-inflammatory painkillers.,Many kidney teams give patients “sick day guidance” advising them to pause these medicines temporarily until they are eating and drinking normally again, usually for 24 to 48 hours. Only follow this if your healthcare team has advised it for you, and seek help if you are not improving.

Eating well with CKD

There is no single kidney diet; advice depends on your stage of CKD, your blood test results and other conditions. In earlier stages, the focus is usually on a heart-healthy diet: plenty of vegetables, fruit, wholegrains and pulses, limited processed foods, and less salt to help control blood pressure.,As CKD progresses, some people need to limit potassium, phosphate, protein or fluid. Potassium is found in foods such as bananas, potatoes, tomatoes, oranges, plantain and dried fruit. Phosphate is found in dairy, processed meats, colas and many processed foods with phosphate additives. Do not cut out food groups without advice; a renal dietitian can help you eat safely while enjoying your food.

Salt and fluid

Reducing salt helps control blood pressure and fluid retention. Aim for less than 5 g of salt a day, about a teaspoon, by cooking from scratch and avoiding salty processed foods, stock cubes and sauces. Fluid restriction is not needed in early CKD, but people with advanced CKD or on dialysis may be asked to limit fluids. Avoid salt substitutes that contain potassium unless your healthcare provider has said they are safe for you.

Anaemia in CKD

As kidney function falls, the kidneys make less erythropoietin, a hormone that stimulates red blood cell production, leading to anaemia. Symptoms include tiredness, breathlessness and feeling cold. Treatment may include iron, often given intravenously, and injections of erythropoiesis-stimulating agents. Your healthcare team will check your haemoglobin and iron levels regularly.

Bone and mineral health

CKD affects the balance of calcium, phosphate, vitamin D and parathyroid hormone, which can weaken bones and cause calcium to build up in blood vessels. This is called CKD mineral and bone disorder. Treatment may include dietary changes, phosphate binders taken with meals, and vitamin D. Regular blood tests guide treatment.

Being referred to a kidney specialist

• eGFR below 30 (stage 4 or 5)
• Large amounts of protein in the urine
• A rapid fall in eGFR
• Blood pressure that is hard to control despite several medicines
• Suspected inherited kidney disease
• Blood or protein in the urine with possible kidney inflammation
• Your healthcare provider may use a kidney failure risk calculator to guide referral

Preparing for kidney failure: your options

If CKD progresses towards kidney failure, you will have time to learn about your options and choose what is right for you. Planning usually starts when eGFR falls below about 20 to 30. The main options are dialysis, a kidney transplant, or conservative kidney management.,There is no right or wrong choice. The best option depends on your health, age, preferences, lifestyle and what is available where you live. Kidney teams usually offer education sessions and chances to talk with people already living with each option.

Haemodialysis

Haemodialysis uses a machine to filter your blood. It is usually done three times a week for about four hours at a time, in a hospital or dialysis unit, though some people dialyse at home. A fistula, a connection between an artery and a vein usually in the arm, is created in advance to provide good access to the blood. Some people use a catheter instead.,Dialysis takes time and can be tiring, but many people continue working, travelling (by booking dialysis at their destination) and enjoying life.

Peritoneal dialysis

Peritoneal dialysis uses the lining of your abdomen (the peritoneum) as a natural filter. A soft tube is placed in your abdomen, and dialysis fluid is drained in and out, either several times during the day or overnight using a machine. It is done at home and offers more flexibility, but requires careful hygiene to prevent infection.

Kidney transplant

A kidney transplant offers the best long-term outcome for many people with kidney failure. Kidneys can come from deceased donors or living donors, often family members or friends. A living donor transplant before dialysis is needed, called pre-emptive transplantation, often gives the best results.,After a transplant, you will need to take anti-rejection medicines for life and have regular check-ups. Not everyone is suitable for a transplant, and waiting times vary greatly between countries and blood groups.

Conservative kidney management

Some people, particularly older people or those with other serious health conditions, choose not to have dialysis. Conservative kidney management focuses on controlling symptoms, protecting remaining kidney function, and maintaining quality of life with support from kidney and palliative care teams. For some people, dialysis may not extend life much while adding a significant treatment burden, so this can be a positive and valid choice.

Living with CKD: everyday tips

• Know your eGFR and ACR numbers and how they are changing
• Keep a list of your medicines and share it with every healthcare provider
• Check your blood pressure at home if advised
• Stay active, aiming for regular moderate exercise
• Do not smoke
• Limit alcohol
• Get vaccinated against flu, pneumococcus and, if advised, hepatitis B
• Keep hydrated, especially in hot weather or illness, unless told to restrict fluids

CKD and pregnancy

Women with CKD can have successful pregnancies, but pregnancy can put extra strain on the kidneys and carries higher risks of pre-eclampsia, early birth and worsening kidney function. Some kidney medicines, including ACE inhibitors and ARBs, should be stopped before or very early in pregnancy. If you have CKD and are thinking about pregnancy, talk to your kidney team first.

Mental health and CKD

Living with kidney disease, especially on dialysis, can be emotionally hard. Depression, anxiety and fatigue are common. Dietary restrictions, time spent on treatment and uncertainty about the future can all affect wellbeing.,Kidney units often have social workers, psychologists or counsellors. Patient support groups and charities can also offer practical help and the chance to talk with others who understand.

Kidney disease around the world

Access to dialysis and transplantation varies enormously between countries. In some places, many people who need dialysis cannot get it or cannot afford it. This makes prevention, early detection and protecting kidney function even more important. Simple, low-cost actions such as checking blood pressure, testing urine for protein, using ACE inhibitors or ARBs where appropriate, and avoiding unnecessary anti-inflammatory painkillers can make a big difference.

Gout, acidosis and other complications

As kidney function falls, uric acid can build up and cause gout flares. Some gout medicines need dose adjustments in CKD. The blood can also become more acidic (metabolic acidosis), which may affect bones and muscles; treatment with sodium bicarbonate is sometimes used.,High potassium is a risk in advanced CKD, especially with certain medicines. Your healthcare team will monitor potassium and may adjust your diet or medicines. Fluid build-up can cause swelling and breathlessness, which may need diuretics.

Kidney stones and CKD

Repeated kidney stones can damage the kidneys over time. If you have had stones, drinking enough fluid to produce pale urine, reducing salt, and following specific dietary advice based on the type of stone can lower your risk. Some people need medicines to prevent stones from forming.

Your regular check-ups

• eGFR and urine ACR at least once a year, more often in later stages
• Blood pressure at every review
• Full blood count for anaemia
• Potassium, calcium, phosphate and bicarbonate as needed
• Cholesterol
• Medicines review whenever eGFR changes
• Diabetes checks if you have diabetes

Questions to ask your healthcare team

• What is my stage of CKD, and is it stable?
• What is causing my kidney disease?
• Which medicines will protect my kidneys and heart?
• Should I see a renal dietitian?
• Do I need a sick day plan?
• When should I start learning about treatment options for kidney failure?

What eGFR numbers feel like in real life

Many people find it helpful to think of eGFR as a rough percentage of normal kidney function, although this is a simplification. An eGFR of 50 roughly means your kidneys are working at about half the rate expected of healthy young kidneys. People can live well with this level of function for many years, often for the rest of their lives, especially if it remains stable.

What matters most is the trend. A slow, steady eGFR is far more reassuring than a rapid fall. Your healthcare team will look at how your results change over months and years, alongside your urine protein, to judge your risk and adjust treatment.

Living kidney donation

Many people with kidney failure receive a kidney from a living donor, often a relative, partner or friend. People can live healthy lives with one kidney. Potential donors go through careful medical and psychological assessment to make sure donation is safe for them. In some countries, “paired exchange” schemes allow people whose blood group or tissue type is not compatible with their loved one to swap donors with another pair. If someone offers to donate, your transplant team can explain the process.

Supporting a family member with CKD

If someone you love has CKD, you can help by learning about their condition, supporting healthier cooking for the whole household, encouraging them to attend appointments and helping them keep track of medicines. For people on dialysis, practical help with transport, meals and household tasks can make a big difference. Look after yourself too, as caring can be demanding over the long term.

Itching, sleep and restless legs

In advanced CKD, itching can be distressing, especially at night. It is often linked to high phosphate levels, dry skin and the build-up of waste products. Keeping phosphate in range, using moisturisers, and specific treatments can help. Restless legs, an uncomfortable urge to move the legs at night, is also common and may improve with treating iron deficiency or dialysis adjustments. Mention these symptoms; they are treatable and not just something to put up with.

A note on herbal and traditional remedies

In many parts of the world, people use herbal or traditional remedies for kidney problems. Some of these, including certain plants containing aristolochic acid, have caused serious kidney damage and kidney failure. “Natural” does not always mean safe. Before taking any herbal product, supplement or traditional medicine, check with a healthcare provider or pharmacist who knows about your kidney disease.

Take one step today

Kidney disease can feel complicated, but you do not have to change everything at once. Start by asking for your numbers, checking your medicines for anti-inflammatory painkillers, and booking your next blood pressure check. Small, consistent steps protect your kidneys over time.

Frequently asked questions

Can CKD be reversed?

Damage is usually permanent, but progression can often be slowed or stopped, especially if found early.

Does drinking lots of water help my kidneys?

Staying hydrated is important, but drinking very large amounts does not improve kidney function and may be harmful in advanced CKD.

Will I definitely need dialysis?

No. Most people with CKD never need dialysis, particularly if their CKD is found early and managed well.

Can I exercise?

Yes. Regular exercise is beneficial for most people with CKD.

Is protein bad for my kidneys?

Very high-protein diets may not be suitable in later stages of CKD. A dietitian can advise on the right amount for you.

But my kidney results say stage 3 and I feel completely fine

That is common, and it is exactly the best time to act. The steps you take now, such as controlling blood pressure, taking kidney-protecting medicines and avoiding harmful painkillers, can keep your kidneys working for many years.

Related: Kidney function tests explained · Early signs of kidney disease · Dialysis and fistula care · High blood pressure: complete guide

Sources: KDIGO 2024 clinical practice guideline for CKD, National Institute for Health and Care Excellence (NG203), International Society of Nephrology, National Kidney Foundation, Kidney Care UK, World Health Organization.