Chronic kidney disease


Photo of patient and doctor

Our kidneys are vital organs that clean our blood and affect many different bodily functions. Various medical conditions can cause the kidneys to stop working properly for a short time – for example, if blood isn’t pumped around the body properly or if an enlarged prostate or kidney stones make urine build up in the kidneys.

But if the kidneys still aren’t working at full capacity more than three months later or are permanently damaged, then the problem is considered to be chronic kidney disease. The most common causes in adults are diabetes and high blood pressure.

Older people are especially prone to developing chronic kidney disease. It often goes unnoticed for a long time because poorly functioning kidneys don’t cause any problems at first.

Treatment mostly aims to stop the kidney disease from getting worse, or at least delay the process. It is also important to treat complications such as anemia, acidosis or changes in bone metabolism. If the kidneys fail completely, dialysis or a kidney transplant can prolong the person’s life.


Chronic kidney disease is often first detected when complications start causing problems or if the kidneys fail. Then the body can’t get rid of enough fluids, and metabolic waste products slowly build up. Symptoms may affect most of the body, including:

  • Swelling (edema), for example in the legs or face
  • Nausea, vomiting, diarrhea
  • Loss of appetite, weight loss
  • Pale skin and itching
  • Tiredness, listlessness, physical weakness
  • Shortness of breath
  • Difficulties concentrating, confusion, problems with consciousness or even loss of consciousness
  • Muscle paralysis, muscle cramps
Illustration: These symptoms may occur alone or in any combination


The most common causes of chronic kidney disease in adults are diabetes and high blood pressure.

Long-term kidney damage may also result from:

  • Inflammation of the kidney tissue
  • Long-term use of medication, especially painkillers
  • Kidney stones, tumors or scars that prevent urine from flowing out
  • Congenital (present at birth) kidney diseases such as polycystic kidney disease


In Germany, it’s estimated that over two million people have long-term problems with their kidney function. Most of those affected are over the age of 60.

About 90,000 people need dialysis each year because their kidneys don’t work well enough on their own. And more than 2,000 donor kidneys are transplanted per year. Kidney transplants make up over half of all organ transplants performed in Germany.

About 10,000 people die from complications of chronic kidney disease each year in Germany.


In the early stages, the kidneys can still clean enough blood although they aren’t functioning properly. This state can last for years, and sometimes the kidneys even get better again.

But they may get worse instead, resulting in kidney failure (renal insufficiency). Over time, the kidneys may fail completely in some people. This is referred to as “end-stage kidney disease,” and it is life-threatening.


People with chronic kidney disease have a greater risk of cardiovascular diseases such as strokes or heart attacks.

The kidneys play an important role in the production of blood and in bone metabolism. Because of this, damaged kidneys may cause anemia, problems with blood clotting and bone damage (renal osteodystrophy).

If the kidneys fail completely, the waste products in the body build up so much that it becomes “poisoned from inside.” The medical term for this is uremia. Among other things, it causes skin changes, gastrointestinal (stomach and bowel) problems and damage to the brain and nerves. It also upsets the balance of fluids and electrolytes in the body, causing acid to build up (acidosis). Possible life-threatening complications of uremia include loss of consciousness, pulmonary edema (build-up of fluid in the lungs) and an irregular heartbeat.


In order to find the causes and determine the severity of chronic kidney disease, the following are necessary:

  • In-depth talk with a doctor (medical history)
  • Physical examination including measurement of blood pressure
  • Ultrasound examination of the abdomen (belly) and kidneys
  • Blood tests for certain substances, including in particular: creatinine, blood sugar and hemoglobin levels and a blood gas analysis to see how much acid is in the blood
  • Urine tests to measure protein levels, for example

Doctors can see how your kidneys are functioning based on these and other blood test results. Other test results can help to determine whether something like diabetes is the underlying cause or whether the kidney disease has already led to complications.

If doctors still need to know more, imaging techniques like (CT) scans or a kidney biopsy (tissue sample) may be helpful.


Diseases like diabetes or high blood pressure increase the risk of chronic kidney disease. If you have either of those conditions, it may be a good idea to have your kidneys checked regularly by your family doctor. That way, signs of kidney failure can be detected early on.

People who have statutory health insurance in Germany can have a free general check-up every three years from the age of 35 onwards (this is called the “Check-Up 35”). The aim of this test is to detect signs of cardiovascular disease, diabetes and kidney problems.


If you lower your risk of diabetes and high blood pressure, you will also lower your risk of chronic kidney disease caused by those conditions. The main things you can do are: avoid becoming overweight and get enough exercise.

People who already have diabetes or high blood pressure often also have to take medication to regulate their blood sugar levels and blood pressure, to try to prevent later complications like chronic kidney disease.


The most suitable treatment for chronic kidney disease will depend on the cause and stage of the disease, as well as on the person’s life circumstances and preferences.

If the kidneys are still working at a nearly normal level, treatment should aim to stop or slow down the progression of the disease. This is mainly done using medication to lower blood pressure levels and prevent cardiovascular disease. If you have diabetes, it's important to regulate your blood sugar levels.

If complications such as anemia or bone metabolism disorders have already occurred, then more medications are used – such as medicines that contain iron or stimulate the production of blood, as well as medications called “phosphate binders.” If there is too much acid in your body, bicarbonates are used. In addition to the medication, the treatment will include a diet suited to the stage of the disease, drinking the right amounts of liquids and physical exercise.

Dialysis or a kidney transplant are considered if the kidneys fail completely.

In the vast majority of people with complete kidney failure, at least one of these options is possible. Some people make a conscious decision not to use either, accepting the fact that they could die soon afterwards. Palliative treatment may then be suitable for them – enabling a final phase of life that is as pleasant as possible.

Everyday life

Chronic kidney disease has an impact on everyday life. People are advised to change their diets and the amount of fluids they drink, for example. Kidney specialists usually offer nutritional counseling specifically for people who have kidney disease and those close to them.

It’s usually important to avoid drinking too much, especially during dialysis. This is because the dysfunctional kidneys can often hardly get rid of any fluid at all, and drinking too much could lead to edema (fluid retention). If people feel thirsty, sour candies, lemon slices or sugar-free gum can help. It is also helpful to

  • use smaller glasses and cups,
  • drink slowly,
  • avoid dry indoor air, and
  • take medication with a meal, if possible, instead of with an extra glass of water.

People with chronic kidney disease often have to manage taking several different medications over a longer period of time. A medication schedule that has an easy-to-read list of what needs to be taken, and when it needs to be taken, can help. Having weak kidneys mean that some types of medication can’t be used: Instead of taking NSAIDs like ibuprofen for pain relief or using tablets for the treatment of diabetes, you will need to talk to your doctor about alternatives. It may be necessary to get used to entirely new treatments, like insulin injections rather than tablets.

Changing your diet, drinking less and taking medication aren’t the only things that can be a burden. Dialysis takes a lot of time and requires adjustments to your daily schedule, which can affect both your private life and work.

In Germany, you can call a free telephone hotline run by the Society of German Kidney Centres (“Verband Deutsche Nierenzentren e. V.”) and the Federal Kidney Association (“Bundesverband Niere e. V.”) for help with these topics and any other issues you may have.

Knowing that you will be dependent on treatment for the rest of your life or feeling like you’re a burden to your family can be hard to deal with and also cause depression. Many people find it helpful to talk with others who have the same condition – for instance, in a support group or during dialysis. You could also seek psychological treatment if you are finding it hard to cope with emotionally.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.

The Federal Kidney Association website has a lot of information and events listings related to the topic of kidney disease, and also provides the contact details and addresses of support groups all across Germany.

Germany’s Federal Centre for Health Education (“Bundeszentrale für gesundheitliche Aufklärung,” or BZgA) has also compiled detailed information (in German) about kidney transplants on the website

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IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Created on March 8, 2018

Next planned update: 2024


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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