What Is Chronic Kidney Disease? Doctors Explain the Causes and How It's Treated
Right now, 37 million Americans are living with chronic kidney disease (CKD), says the National Kidney Foundation (NKF). When you have this medical condition, it means your kidneys—the bean-shaped organs located on either side of your spine—are damaged and can't filter your blood the way they should. While it can be devastating to get this diagnosis, most people with the disease are still able to live healthy and productive lives.
"When people learn that they have chronic kidney disease, they automatically assume they'll need dialysis, but with proper treatment, they can manage this disease well for years," David Goldfarb, MD, clinical chief of nephrology at NYU Langone Health in New York City tells Health.
Case in point: celebrities like Selena Gomez, Sarah Hyland, and Halle Berry are still thriving even with CKD diagnoses, says the NKF. If you're among the 15% of Americans living with chronic kidney disease, here's what experts want you to know.
What are the causes of chronic kidney disease?
To understand what causes CKD, it helps to have a primer on normal kidney function. Your kidneys work to clean your blood, removing things like waste and excess water, says the NKF. (Think of them as your own personal body filters). Blood enters your each of your kidneys through your renal arteries, says the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). From there, it's put through millions of tiny blood filters known as nephrons to be cleaned, before waste material is sent to your bladder as urine.
Normally, healthy kidneys work like a well-oiled machine, filtering about 200 quarts of fluid every 24 hours, says the NKF. (Only about two quarts of that are peed out; the remaining 198 quarts are sent back as cleaned blood throughout your body). But in order for them to work properly, the arteries leading to your kidney need to be healthy, as do the nephrons. If they're not, you can run into trouble.
Things that can cause problems include:
Diabetes. This is the number one cause of kidney disease, says the NKF. When your blood sugar is too high, it injures all the small blood vessels in your body, including those in your kidneys. As a result, your kidneys can't filter your blood properly. About 30% of people with type 1 diabetes and up to 40% of those with type 2 will ultimately experience kidney failure.
High blood pressure. When you have hypertension, the pressure of your blood against the walls of your blood vessels increases, explains Dr. Goldfarb. This damages them, including the vessels that bring blood to and from your kidneys.
Glomerulonephritis. This is a group of diseases that damage the blood-filtering nephrons, . nephrons in your kidneys, says the NKF. As a result, they can't filter your blood properly.
Autoimmune diseases such as lupus. These disorders can cause your immune system to attack any organ in your body, including your kidneys, notes the NIDDK.
Recurrent kidney infections. In rare cases, repeated kidney infections can cause kidney scarring, which can lead to chronic kidney disease, says the NIDDK.
What are the symptoms of chronic kidney disease?
About 90% of people with kidney disease don't realize that they have it, says the NKF.
"Most patients don't develop signs of the disease until it's fairly advanced," Staci Leisman, MD, a kidney specialist at Mount Sinai Hospital in New York City tells Health. That being said, there may be some symptoms that start earlier, she notes. These include:
Swollen ankles and feet. As your kidney function goes down, your body is less able to filter out salt, explains Dr. Leisman. It can build up, causing swelling in your feet and ankles (aka cankles).
Anemia. When you have kidney disease, your kidneys have trouble producing erythropoietin (EPO), a hormone that tells your body to make red blood cells, explains the NIDDK. As a result, your red blood cell count drops. Your doctor may pick this up on a routine lab test, or you may notice that you feel weak and tired, and have other symptoms such as dizziness, shortness of breath, and trouble thinking clearly.
A metallic taste in your mouth. When you have kidney disease, waste products build up in your body, including one known as urea, says Dr. Leisman, which can affect your taste buds.
Peeing more at night. When your kidney filters are damaged, you can feel the urge to pee more often. This can be especially noticeable at night when you lie down, since the extra fluid around your ankles, feet and legs can now flow up to your kidneys, explains Dr. Leisman.
Later signs of kidney disease include:
- Trouble concentrating.
- Difficulty sleeping.
- Dry and itchy skin.
- Blood or "foamy" urine.
- Decreased appetite.
By the time these symptoms hit, "you've really missed the window to treat your chronic kidney disease," says Dr. Leisman. As a result, your kidneys have become so damaged they're no longer able to filter out most toxins, leading them to build up in your bloodstream.
How is chronic kidney disease diagnosed?
There are two main tests doctors use to diagnose chronic kidney disease, says Dr. Goldfarb. They are:
- Glomerular filtration rate (GFR). This is a blood test to check how well your kidneys filter blood. A GFR of at least 60 is considered normal, says NIDDK, while less than that indicates kidney disease A number of 15 or less means kidney failure.
- Urine test. This checks for albumin, a protein that can show up in your urine if your kidneys are damaged, per the NIDDK.
If you have kidney disease, your doctor will also run these tests periodically to make sure your current treatment is working. This means an GFR that stays the same or rises, and a urine albumin level that goes down.
Chronic kidney disease treatment
If you're diagnosed with chronic kidney disease, you'll need to see a nephrologist, or kidney doctor. Research shows that the earlier you're referred to one, the less chance you have to develop complications from your CKD, according to the NKF. There's no cure for CKD, but most people are able to manage it with the following steps.
- Control your blood pressure. "This is probably the most important part of treatment for people with CKD," says Dr. Goldfarb. Up to 85% of people with CKD have high blood pressure, but if you get it under control, you can slow its progression, he notes. Two classes of blood pressure medications—angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB) have been shown both to lower blood pressure and protein levels in urine.
- Watch your diet. People with CKD should have no more than 1,500 milligrams of salt a day. "When your kidneys are damaged, they can't filter out sodium very well, which means it can stay in your body and raise your blood pressure," says Dr. Leisman. You should also go easy on the protein, as it's hard on your kidneys. Sometimes, people with CKD develop high blood potassium and/or high blood phosphate levels, so they need to scale back on certain foods. It's a good idea to work with a dietitian to come up with a doable meal plan: since you have CKD, it's often covered by insurance.
- Keep tabs on your cholesterol and blood glucose levels. These are both often elevated in people with CKD, says Dr. Goldfarb. You may need cholesterol lowering medications such as statins, as well as medications to control type 2 diabetes.
- Be careful with OTC medications. If you have CKD, you want to avoid taking any product that contains nonsteroidal anti-inflammatory drugs (NSAIDs) to treat pain, fever or cold symptoms. NSAIDs can damage your kidneys even further, says the NKF. It's a good idea to always check with your pharmacist or physician before you take any new OTC product.
- Watch your weight. Extra pounds force your kidneys to work harder, since they have to filter more waste. Regular exercise is also key. One large review published in 2019 in the journal BMC Nephrology found that staying active boosted GFR rate and also helped keep other medical conditions like high blood pressure under control.
With these steps, you may be able to keep your kidneys functioning healthfully for years. But some people find that despite their efforts, they have developed kidney failure, which is when your GFR rate falls to less than 15%. If this happens, there are two main options: dialysis, a treatment that filters your blood using a machine, or a kidney transplant. While this sounds scary, it's important to remember that out of the 37 million Americans living with the disease, less than 800,000 a year require either.
"In general, we're more concerned about someone with chronic kidney disease having a heart attack or stroke because of other cardiovascular risk factors than we are about them eventually needing dialysis," says Dr. Goldfarb. That's why it's so important to get those other risk factors under control too.
Can you prevent chronic kidney disease?
While there's no magic bullet to prevent CKD, you can help lower your risk by following a healthy lifestyle, says Dr. Goldfarb. A few pointers:
- Eat a healthy diet. A 2019 review of 18 studies published in the Clinical Journal of the American Society of Nephrology found that a healthy diet rich in fruits, veggies, legumes, nuts, whole grains, fish, and low-fat dairy was associated with a 30% lower incidence of CKD That diet was also linked to a 23% lower rate of albuminuria, an early indicator of kidney damage.
- Stay active. The more exercise you get, the lower your risk of kidney disease, according to a 2020 study published in the British Journal of Sports Medicine. When researchers followed almost 200,000 Taiwanese adults without kidney disease for 18 years, they found that those who were the most physically active were 9% less likely to develop kidney disease over that time period than those who were more sedentary.
- Don't smoke or drink too much. Smoking slows blood flow to all of your major organs, including your kidneys, says the NKF, while excessive alcohol consumption boosts blood pressure and the risk for CKD, it notes. An occasional drink is fine, but keep it in moderation—both regular heavy drinking and binge drinking raise chances of kidney damage.
To get more inspiring stories delivered to your inbox, sign up for the Healthy Living newsletter