Your Guide to Chronic Kidney Disease Staging

by Sarah Ludwig Rausch Health Writer

You probably don’t think about your kidneys too much. They work behind-the-scenes, filtering waste from your blood and dumping toxins out in your urine. However, they’re easily damaged from other health conditions. When you have diabetes, high blood pressure (HBP), or a genetic kidney disease, the million or so microscopic filtering units in your kidneys can become scarred, making it harder to filter your blood. This causes even more damage—and chronic kidney disease (CKD). An estimated 37 million people in the U.S. have CKD, yet most are undiagnosed, probably because symptoms don’t show up until later stages.

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Kidney Functionality Determines Your Diagnosis

When you’ve lost kidney function or have kidney damage, and either lasts for three months or longer, you have CKD. Anything less than three months is called acute kidney disease, explains James Simon, M.D., a nephrologist at Cleveland Clinic’s Glickman Urological & Kidney Institute in Ohio. Your doctor will do bloodwork that reveals your glomerular filtration rate (GFR), an estimated percentage of kidney function—which determines which stage of CKD you’re in. (GFR is derived from a blood test that measures a waste product called creatinine.) CKD has five stages. Here’s what’s happening in each stage.

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Stage 1: Damage With High Kidney Function

In Stage 1, your GFR is 90 or more—your kidneys are functioning at 100%. What drives a diagnosis of CKD is evidence of kidney damage—protein or blood in your urine, or kidney abnormalities like cysts seen on an ultrasound, says Mohamed Atta, M.D., professor of medicine in the division of nephrology at the Johns Hopkins University School of Medicine in Baltimore. You won’t have any symptoms unless you have a genetic kidney disease (pain, bloody urine, infection, and kidney stones) or an immunological kidney disease (puffy eyes, frothy urine, and leg swelling), Dr. Atta says.

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Stage 2: Higher GFR With High Kidney Function

The only difference between stages 1 and 2 is your GFR is between 60 and 89 in the second stage, and this means your kidneys are likely still working well. As with Stage 1, you must have blood or protein in your urine or kidney abnormalities (like polycystic kidney disease). And, you likely won’t have symptoms unless you already have a genetic or immunological kidney disease, which is why Dr. Atta says CKD at Stage 2 is most often found from an ultrasound or an abnormal blood or urine test taken to monitor those conditions.

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Stage 3: Kidney Damage With Cardiovascular Risks

There are two stages within this stage: 3a (GFR 45 is to 59) and 3b (GFR is 30 to 44). Both indicate some kidney damage. “This is the stage where we catch most people,” Dr. Simon says, though most still don’t have symptoms. Kidney damage usually increases blood pressure, so it can be harder to control now, upping your risk of a stroke or heart attack—even more than the odds of you eventually needing dialysis. (“Many people in Stage 3 never progress to stages 4 or 5,” notes Dr. Simon). You’ll now see a nephrologist to work on reducing your cardiovascular risks.

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Controlling Diabetes and HBP in Stage 3 Is Key

CKD treatment in this stage mostly consists of treating the underlying condition that is causing your kidney problems. If you have diabetes or HBP, the most common causes of CKD, your doctor will focus on making sure they’re well-controlled. Why? Because both diseases play into the whole vicious circle of scarring that occurs in the filtration units in your kidneys. Leave either condition unchecked, and more kidney damage occurs. “[Management of] blood pressure and diabetes are predictors of how the kidneys stabilize or continue to progress in most people,” Dr. Simon says.

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Treatment for Stage 3 CKD

If you have protein in your urine, your doctor may put you on an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB), heart meds that lower blood pressure. Dr. Simon says they also have anti-inflammatory properties that can slow CKD disease progression. He adds that statins have been shown to reduce heart attacks and strokes in kidney patients, too. Finally, he recommends a heart-healthy diet that’s low in sodium and fat, and says to steer clear of nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, aspirin, and naproxen sodium—they can damage your kidneys by restricting blood flow to them.

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Stage 4: Pre-Kidney Failure

In Stage 4, your GFR is between 15 and 29, which means your kidneys have moderate to severe damage. “We consider it pre-kidney failure,” says Dr. Simon. “Something happens when you get down into Stage 4, and the risk of you going on to kidney failure goes up a lot, so we pay a lot closer attention to you.” He says you may feel more fatigue, but most people don’t have symptoms until they’re well into Stage 5. About once a month your nephrologist will monitor your blood pressure and make sure your other health conditions are under control.

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Treatment for Stage 4 CKD

If you aren’t already on one, your nephrologist may start you on an ACE inhibitor or ARB to slow down progression of CKD. They will perform regular blood and urine tests to diagnose and treat complications of CKD such as anemia, acidosis, and mineral bone disease. They may also discuss a treatment plan in case you go into kidney failure so that you have time to prepare. Your options at that point will be dialysis—a therapy that cleans your blood—or a kidney transplant. Dialysis can be done in a hospital, at a dialysis center, or even at home, but “(it’s) not a perfect replacement for kidney function,” Dr. Simon says. “The cure is a kidney transplant,” notes Dr. Atta.

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CKD Stage 5: Kidney Failure (or Close to It)

In Stage 5, your GFR is less than 15. This means your kidneys are close to completely failing. Although people also refer to this stage as end-stage kidney disease (ESKD), Dr. Simon says they’re different. You’re only officially in ESKD when you’ve started dialysis or you’ve had a kidney transplant. Stage 5 means you haven’t gotten to that point yet, but your doctor is following you very closely. Dr. Simon says symptoms that toxins are building up and you’re moving into ESKD include nausea, appetite loss, vomiting, and a metallic or burning taste in your mouth.

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Treatment for Stage 5 CKD

Once you’ve gone into kidney failure, you’ll need dialysis or a kidney transplant. “Transplant is the gold standard,” says Dr. Simon. “A lot of people think transplant is severe, but we would rather transplant than put people on dialysis—they live longer and they have a more normal life.” If you can find one, you can actually get a transplant from a living donor before your kidneys totally fail. Not everyone is eligible for a transplant though—for instance, some people are too sick or too advanced in age—so you may need to prepare for dialysis.

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How Dialysis Works

If you do end up needing dialysis, you’ve probably already prepared for it with your doctor. There are two kinds—hemodialysis and peritoneal. Going to a hospital or dialysis center will take around four hours, three times a week, says Dr. Simon. You may also do either type at home, even at night while you sleep. When you’re on dialysis, you’ll probably have to watch your potassium intake, which can be tricky on a heart-healthy diet since potassium-rich foods are all fruits and vegetables, Dr. Simon says. Deep breath: Dialysis isn’t easy, but you can potentially do it for years.

Sarah Ludwig Rausch
Meet Our Writer
Sarah Ludwig Rausch

Sarah Ludwig Rausch is a health writer and editor whose specialties include mental health, diseases, research, medications, and chronic conditions. She’s written for The Christian Science Monitor, American Cancer Society, Cleveland Clinic, PsychologyToday.com, MedShadow Foundation, the ACT Test, and more.