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22nd February, 20218 min read

Chronic kidney disease: All you need to know

Medical reviewer: Dr Ann Nainan
Last reviewed: 11/02/2021
Medically reviewed

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What is chronic kidney disease?

Chronic kidney disease (CKD) is a condition that reduces how well your kidneys work in the long term.
But what exactly do your kidneys do?

Filtering waste products from the blood before turning them into pee is their main role, but these hard-working, bean-shaped organs, located just below the ribcage on either side of the body, are responsible for many other things. These include:

  • maintaining your blood pressure
  • maintaining your body’s fluid balance
  • maintaining the correct levels of certain chemicals in the body
  • removing waste from the blood
  • producing a substance called erythropoietin, which helps stimulate the production of red blood cells
  • making certain hormones
  • turning vitamin D from the sun or supplements into a form your body can use

What are the symptoms of chronic kidney disease?

The body can cope with a large fall in kidney function. That’s why most people with CKD have no early symptoms of the disease.

But symptoms of CKD usually do appear in the later stages, and can include:

  • swollen ankles, feet or hands
  • puffy eyes
  • shortness of breath
  • feeling sick
  • tiredness
  • blood in your pee
  • losing weight without meaning to
  • muscle cramps
  • dry, itchy skin
  • trouble thinking clearly
  • needing to pee often

If your kidney function falls really low, you may notice other symptoms and eventually develop kidney failure.

When to take action

Many other conditions and changes in your body can lead to symptoms like those caused by CKD. See a doctor as soon as possible if you have any of the above symptoms. They will be able to check what’s causing your symptoms and advise you on the best way to manage them.

What causes chronic kidney disease?

Conditions and factors that damage or put a strain on the kidneys can cause CKD.

These include:

  • old age – kidney function tends to fall with age and it’s thought that around 1 in 2 people aged 75 or older have CKD
  • diabetes - diabetic kidney disease can be caused by type 1 and type 2 diabetes
  • high blood pressure – if untreated (or badly managed), high blood pressure can lead to CKD
  • glomerulonephritis – a type of kidney inflammation
  • repeated kidney infections
  • conditions that stop pee from flowing out of the kidneys as normal – this includes kidney stones and an enlarged prostate
  • polycystic kidney disease – an inherited type of kidney disease

You’re also at higher risk of getting CKD if you’re Black or south Asian.

Diagnosing chronic kidney disease

CKD is usually diagnosed through blood and urine tests.

Blood test

The blood test that’s often used to check for CKD is called an estimated glomerular filtration rate (eGFR). It reflects how efficiently your kidneys clear a waste product called creatinine from your blood. If your kidneys are healthy, your eGFR should be at least 90ml/min. But if you have CKD, your eGFR will generally be lower than this.

Urine test

Healthy kidneys leak small amounts of protein into the urine, but when you have CKD, more protein than normal enters your pee. That’s why you’ll usually be given a urine test to check for protein in your pee if a doctor thinks you may have CKD.

They will also usually check your pee for blood and specific levels of creatinine and albumin (another type of protein), which can also suggest CKD.

Imaging tests and biopsy

In some cases, a doctor may recommend other tests to check for signs of kidney damage. These include:

  • imaging tests – such as MRI, CT or ultrasound scans
  • kidney biopsy – a small sample of tissue is taken from your kidney and looked at under a microscope to check for damage to the kidney cells

What are the 5 stages of chronic kidney disease?

CKD is typically split into 5 stages. These stages are based on eGFR results and other factors that show how much the kidney disease has progressed. The higher the number of the stage, the more severe the disease.

Stage 1

Your eGFR is normal (over 90ml/min), but other testing shows signs of kidney damage.

Stage 2

Your eGFR is slightly lower than it should be (60 to 89ml/min), and there are other signs of kidney damage.

If you have stage 1 or stage 2 CKD, you will usually need yearly eGFR tests to carefully monitor the progression of the condition.

Stage 3

This stage is divided into 2 stages: stage 3a and 3b. In stage 3a, your eGFR is 45 to 59ml/min and in stage 3b it’s 30 to 44ml/min. If you have stage 3a or 3b CKD, you’ll also need regular tests (more than 1 a year) to monitor your kidney function.

Stage 4

In stage 4 CKD, your eGFR is very low, around 15 to 29ml/min and you may have symptoms of CKD. You’ll need regular tests and you’ll usually be referred to a kidney specialist (nephrologist) for specialist management and treatment.

Stage 5

Stage 5 CKD is also known as end-stage kidney failure because your kidneys have lost almost all of their function (eGFR is less than 15ml/min).

Only a small number of people with CKD reach stage 5 CKD, but if you do, you’ll usually need kidney dialysis to help remove the waste from your body that your kidneys can no longer remove. You may also need a kidney transplant.

Speak to your nephrologist for more information about dialysis or a transplant. They will usually be able to help guide you through the process of making the decision to have (or not have) these treatments.

How is chronic kidney disease treated?

There’s no cure for CKD. Instead, treatment focuses on 4 things:

  • Managing your symptoms
  • Reducing the risk of developing cardiovascular disease
  • Slowing down the progression of CKD
  • Treating any kidney condition you already have that may make CKD worse

The treatment you’ll get usually depends on the stage of the disease, but may involve:

  • medication – to control your blood pressure, reduce your cholesterol levels and help your body remove excess water
  • lifestyle changes – including losing weight if you need to, exercising regularly, limiting your salt intake to less than 1 teaspoon (6g) a day, cutting down on alcohol to less than 14 units per week
  • dialysis – in the later stages of CKD, your kidney usually loses most of its function. When this happens, dialysis can be used to carry out some of your kidney's normal functions
  • kidney transplant – only a small number of people with CKD reach the last stage. If this happens, you may need a kidney transplant

How can I prevent chronic kidney disease?

If you have a condition like high blood pressure or diabetes that puts you at greater risk of developing CKD, you can help prevent CKD by making sure your condition is carefully managed. This means taking your medication as advised by a doctor, having regular check-ups and speaking to a doctor if you notice any changes in your symptoms.

Making certain lifestyle changes can also help to reduce your risk of CKD. Such changes include:

  • quitting smoking
  • eating a healthy, balanced diet – speak to a nutritionist or dietician for advice on what that means for you
  • cutting down on salt – you should eat no more than 6g a day (that’s the same as a teaspoon)
  • drinking no more than 14 units of alcohol each week – aim to spread your drinking evenly over a week. Read more about what a unit of alcohol looks like
  • not using over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, except when advised to by a doctor or pharmacist
  • losing weight if you’re overweight or obese
  • exercising for at least 30 minutes a day, 5 times a week

Where to get help and advice for chronic kidney disease

If you have CKD, there are many charities, support groups and services that can help you adjust to life with the condition. These include:

You can also speak to a doctor for advice on local services and support groups.

Key points

  • CKD affects the kidneys’ ability to filter waste products from the blood
  • CKD has many causes, but is most commonly caused by old age, diabetes and high blood pressure
  • CKD is most common in the elderly, Black people and in south Asian people
  • there are 5 stages of CKD and treatment depends on the stage of the disease
  • lifestyle changes that help reduce high blood pressure and diabetes risk can help prevent CKD
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