Chronic Kidney Disease
Chronic kidney disease affects more than 1 in 7 American adults, yet as many as 9 in 10 don’t know they have it. While this long-term condition slowly damages the kidneys and has no cure, you can take steps to protect your kidneys and live a full life.
Table of contents
- What is chronic kidney disease?
- Understanding your kidneys
- Stages of chronic kidney disease
- What causes chronic kidney disease?
- Signs and symptoms
- How is chronic kidney disease diagnosed?
- Health problems caused by kidney disease
- Treatment and management
- Living with chronic kidney disease
- Preventing kidney disease
What is chronic kidney disease?
Chronic kidney disease, also called CKD, is a condition where your kidneys are damaged and cannot filter blood as well as they should[1]. The word “chronic” means that kidney function slowly decreases over time[3]. This damage causes waste products, toxins, and excess water to build up in your blood, which can make you sick[3].
Chronic kidney disease is characterized by the presence of kidney damage or an estimated glomerular filtration rate (eGFR)—a measure of how well your kidneys filter blood—of less than 60 mL/min/1.73 m², lasting for 3 months or more[4]. CKD is a common condition that often develops as people get older, and it can affect anyone, though it is more common in people who are Black or of South Asian origin[6].
More than 35.5 million US adults are estimated to have CKD, and most are undiagnosed[5]. About 40% of people with severely reduced kidney function who are not on dialysis are not aware they have CKD[5]. CKD can progress to kidney failure, also called end-stage kidney disease (ESKD), where the kidneys stop working altogether. However, not everyone with CKD will develop kidney failure, and with proper treatment, the disease can often be slowed[3].
Understanding your kidneys
You have two kidneys, each about the size of your fist or a computer mouse. They are bean-shaped organs located toward your back, on either side of your spine, just underneath your rib cage[3]. Your kidneys work hard around the clock—they filter all the blood in your body every 30 minutes[2].
Your kidneys’ main job is to clean your blood by removing waste products, toxins, and excess water, which leave your body as urine[3]. But they do much more than that. They also help control blood pressure, make hormones that produce red blood cells, turn vitamin D into its active form so your body can use it, balance the amount of salt and potassium in your body, and keep your bones strong[2][3]. Kidneys that function properly are critical for maintaining good health[5].
Stages of chronic kidney disease
Chronic kidney disease is divided into five stages based on how well your kidneys are able to filter waste from your blood[3]. Blood and urine tests determine which stage you are in. The stages range from very mild kidney damage (stage 1) to kidney failure (stage 5). Healthcare providers determine the stage of your kidney function according to the glomerular filtration rate (GFR), which is a number based on the amount of creatinine, a waste product, found in your blood[3].
Stage 1 (GFR 90 and higher): Your kidneys are working well, but you have signs of mild kidney damage[3].
Stage 2 (GFR 60 to 89): Your kidneys are working well, but you have more signs of mild kidney damage[3].
Stage 3a (GFR 45 to 59): Your kidneys aren’t working as well as they should and show mild to moderate damage. This is the most common stage, and you may notice symptoms at this stage[3].
Stage 3b (GFR 30 to 44): Your kidneys show moderate damage and don’t work as well as they should. With the right treatment, many people can stay in this stage and never advance to stage 4[3].
Stage 4 (GFR 15 to 29): You have very poor kidney function; your kidneys are severely damaged and close to not working[3].
Stage 5 (GFR less than 15): Your kidneys are very close to failing or have stopped working. You may need kidney dialysis or a kidney transplant at this stage[3].
The classification also includes staging based on levels of albuminuria—the presence of a protein called albumin in the urine, which is a sign of kidney damage[4].
What causes chronic kidney disease?
Chronic kidney disease is usually caused by other health conditions that put strain on the kidneys over time. Often, it results from a combination of different problems[6].
The two most common causes of CKD in adults are diabetes and high blood pressure[2][5]. In the United States, diabetes and high blood pressure are responsible for most cases of kidney disease[5]. Approximately 1 in 3 adults with diabetes and 1 in 5 adults with high blood pressure may have chronic kidney disease[18].
Other conditions that can cause CKD include[6]:
- High cholesterol, which can cause a build-up of fatty deposits in blood vessels supplying the kidneys
- Kidney infections
- Glomerulonephritis—kidney inflammation
- Polycystic kidney disease—an inherited condition where growths called cysts develop in the kidneys
- Blockages in the flow of urine, such as from kidney stones that keep coming back or an enlarged prostate
- Long-term, regular use of certain medicines, such as lithium and non-steroidal anti-inflammatory drugs (NSAIDs)
You are at higher risk for kidney disease if you have a family history of certain genetic conditions like polycystic kidney disease or some autoimmune diseases like lupus. Your risk also increases as you get older[2]. Heart disease and obesity are also risk factors for CKD[5].
Signs and symptoms
There are usually no symptoms of kidney disease in the early stages[6]. Many people don’t have any symptoms until their kidney disease is very advanced[2]. The disease may only be diagnosed if you have a blood or urine test for another reason and the results show a possible problem with your kidneys[6].
At a more advanced stage, symptoms can include[6]:
- Tiredness or feeling very tired
- Swollen ankles, feet, or hands
- Shortness of breath
- Feeling sick or nauseous
- Blood in your urine
You should see a doctor if you have persistent or worrying symptoms that you think could be caused by kidney disease[6].
How is chronic kidney disease diagnosed?
CKD can be diagnosed using blood and urine tests[5]. These tests look for high levels of certain substances in your blood and urine that are signs your kidneys are not working properly. Blood and urine tests are the only way to know if you have kidney disease[5].
The blood test measures creatinine levels and calculates your estimated glomerular filtration rate (eGFR), which shows how well your kidneys are filtering waste[3]. The urine test checks for albumin, a protein that shouldn’t be present in urine if kidneys are working properly[4]. Your doctor may also use the albumin-creatinine ratio (ACR) from a urine sample to assess kidney damage[4].
If you are at high risk of developing kidney disease—for example, if you have diabetes, high blood pressure, heart disease, or a family history of kidney failure—you may be advised to have regular tests to check for CKD so it can be found at an early stage[6]. Testing may be the only way to know if you have kidney disease, and the sooner you know, the sooner you can get treatment[7].
When possible, serum cystatin C—another substance in the blood—should be measured to confirm eGFR in patients with CKD[4].
Health problems caused by kidney disease
Because damaged kidneys can’t filter blood properly, CKD can lead to other serious health problems[5]. These include:
- Heart disease and stroke: CKD increases your risk of cardiovascular disease, including heart attack and stroke. Even if you have mild CKD, you are at increased risk of developing these problems. Cardiovascular disease is one of the main causes of death in people with kidney disease[6].
- Anemia or low number of red blood cells[5]
- Increased occurrence of infections[5]
- Low calcium levels, high potassium levels, and high phosphorus levels in the blood[5]
- Loss of appetite or eating less[5]
- Depression or lower quality of life[5]
- Bone disease[4]
CKD also affects cognitive function, bone metabolism, and blood pressure[4].
Treatment and management
There is no cure for chronic kidney disease, but treatment can help relieve symptoms and stop it from getting worse[6][13]. Your treatment will depend on the stage of your CKD.
Controlling blood pressure
The most important step you can take to treat kidney disease is to control your blood pressure[22]. High blood pressure can damage your kidneys, so you can protect them by keeping your blood pressure at or less than the goal set by your healthcare provider. For most people, the blood pressure goal is less than 140/90 mm Hg, though some may need to aim for less than 130/80 mm Hg[6][22].
Medicines called angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are often used to lower blood pressure and protect the kidneys[6][13]. These medicines may be particularly important if you also have diabetes or protein in your urine[13].
Managing diabetes and blood sugar
If you have type 2 diabetes or a high albumin-to-creatinine ratio, you may be offered a type of medicine called an SGLT2 inhibitor, such as dapagliflozin, which helps lower blood sugar and can reduce damage to your kidneys[13]. You may also be given an additional medicine called finerenone, which works by blocking certain hormones that can damage your kidneys[13].
Controlling blood sugar is very important if you have diabetes and CKD. Reaching your blood glucose goal can help slow the progression of kidney disease[22].
Managing cholesterol
You may be prescribed medicines called statins to reduce your risk of developing cardiovascular disease. Examples include atorvastatin and simvastatin[13].
Managing other complications
People with CKD can develop high potassium levels in their blood, called hyperkalaemia, because their kidneys do not work properly. A medicine called sodium zirconium cyclosilicate can be used to treat this in certain situations[13].
Advanced treatment options
In advanced CKD (stage 5), treatment options include[6][13]:
- Dialysis: A treatment to replicate some of the kidney’s functions by filtering waste from the blood. There are two main types: hemodialysis, where blood is cleaned through a machine, and peritoneal dialysis, where fluid is put into your abdomen to remove toxins.
- Kidney transplant: A surgical procedure to replace your failing kidney with a healthy kidney from a donor.
Living with chronic kidney disease
Taking an active role in managing CKD will help you feel better and improve your overall well-being[18]. Many people with CKD are able to live long lives with the condition[6]. Although it’s not possible to repair damage that has already happened to your kidneys, CKD will not necessarily get worse[20].
Take your medicine
It’s very important that you take any prescribed medicine, even if you feel well. Some medicines are designed to prevent serious problems in the future[18][20]. Check with your care team if you plan to take any painkillers or nutritional supplements, as these can sometimes affect your kidneys or interfere with your medicine[18].
Eat a healthy diet
A healthy, balanced diet can help improve your general health and reduce your risk of developing further problems[18][20]. Choosing healthy foods and drinks can help you feel better and help keep your kidneys healthier longer[7].
You should limit salt in your diet. While you should reduce salt, your food doesn’t have to be bland. Get creative with herbs, spices, mustard, and flavored vinegars in your favorite recipes[18]. Cooking food at home instead of eating out at restaurants will also help reduce your salt intake[18].
Work with a healthcare professional or registered dietitian to create a meal plan that includes foods you enjoy and that can help protect your kidneys[7]. If blood tests show you have high levels of potassium and phosphate, a dietitian can give you advice about changes you can make to your diet[20].
Be physically active
Physical activity is good for anyone with kidney disease, whether you have mild, moderate, or severe CKD[18]. Regular physical activity can boost your energy, help you sleep, strengthen your bones, help prevent depression, and reduce your risk of problems such as heart disease[18][20]. Exercise is also important for managing kidney disease, and you should aim to do at least 150 minutes per week[13].
If you have mild to moderate CKD, you should be able to be active as often as someone with healthy kidneys. If you have later-stage CKD, you may become tired more quickly, but exercise is still beneficial[18][20].
Other healthy habits
Additional steps to help manage CKD include[18][20]:
- Stop smoking if you smoke. Smoking can make kidney disease worse and interfere with medicine that lowers blood pressure.
- Limit how much alcohol you drink. Manage your alcohol intake so you drink no more than the recommended limit of 14 units of alcohol a week.
- Lose weight if you are overweight or obese.
- Get enough sleep.
- Find healthy ways to cope with stress and depression.
- Get your annual flu shot and the pneumococcal vaccination[20].
Work with your healthcare team
You will have regular contact with your care team to monitor your condition[20]. Learn all you can about kidney disease and especially your own condition. Believe in yourself—there are people and resources to help you become your own best advocate[26]. If you don’t understand something or if something seems wrong, speak up and ask for help[26].
Preventing kidney disease
You can help prevent CKD by making healthy lifestyle changes and ensuring that any underlying conditions you have are well controlled[6]. Steps to reduce your risk include[5][13]:
- Keep your blood pressure below 140/90 mm Hg (or the target your doctor sets for you).
- If you have diabetes, stay in your target blood sugar range as much as possible.
- Get active—physical activity helps control blood pressure and blood sugar levels.
- Lose weight if needed.
- Get tested for CKD regularly if you’re at risk.
- Stop smoking.
- Manage your cholesterol levels.
- Choose foods that are healthy for your heart: fruits, vegetables, whole grains, and low-fat dairy foods.
- Restrict your salt intake to less than 6 grams a day[13].
Early recognition of CKD is the first step in treating it[4]. If you have CKD, even if it’s mild, taking steps early can help slow kidney damage and prevent more serious problems[7].
