What Is Chronic Kidney Disease?
Reviewed by: HU Medical Review Board | Last reviewed: December 2022 | Last updated: January 2023
Each of your kidneys is about the size of a fist and shaped like a red bean. The kidneys' main job is to filter extra water and waste out of the blood and make urine. They also make hormones that help control blood pressure, trigger the body to make red blood cells, and help balance calcium in your body.1
Each kidney is made up of millions of tiny filtering units called nephrons. Each nephron is made of a glomerulus and a tubule. The glomerulus filters your blood, and the tubule returns nutrition to your blood and removes waste. Chronic kidney disease (CKD) is a long-term health condition in which the kidneys are unable to remove extra water and waste properly.1,2
Causes of kidney disease
Diabetes and high blood pressure are the most common causes of kidney disease. Diabetes damages the kidneys’ tiny filters over time. High blood pressure damages blood vessels over time, including the blood vessels in the kidneys. In turn, kidney damage causes blood pressure to rise even more, creating a cycle that is hard to manage.3
Many other health conditions also can cause CKD, including:3-7
- Heart and blood vessel disease
- Genetic disorders like polycystic kidney disease or Alport syndrome
- Drug use that damages the kidneys
- Autoimmune diseases that cause glomerulonephritis (kidney inflammation), such as lupus, Goodpasture's syndrome (anti-GBM disease), IgA nephropathy, and ANCA-associated vasculitis
- Lead or other heavy metal poisoning
- Renal artery stenosis (narrowing of the arteries that feed blood to the kidneys)
- Family history of kidney failure
Diagnosing kidney disease
There are 2 main tests to see if someone has kidney disease:8
- A blood test called GFR. GFR stands for glomerular filtration rate. This number tells your doctor how well your kidneys are working.
- A urine test to look for albumin. Albumin is a measure of protein in your pee. Protein in the urine is a sign of kidney damage.
Your doctor should run these tests every year if you have high blood pressure, diabetes, heart disease, or a family history of kidney disease. Knowing your GFR number allows you to work with your doctor to help protect your kidneys through treatment and lifestyle changes.8
Stages of kidney disease
There are 5 stages of chronic kidney disease. Each stage is based on your GFR test, which measures the amount of kidney function you have. As CKD gets worse, the GFR number gets lower.8,9
The 5 stages of CKD are:9
- Stage 1 – GFR of 90 or higher
- Stage 2 – GFR of 60 to 89
- Stage 3 – GFR of 30 to 59
- Stage 4 – GFR of 15 to 29
- Stage 5 – GFR lower than 15
Managing chronic kidney disease
There is no cure for chronic kidney disease. But there are many things you can do to protect your kidneys from further damage. This may seem hard if you have no symptoms, but managing your disease can improve your overall health.10
The first, most important, step you can take is to control your blood pressure. For most people with CKD, the goal is less than 120 mmHg for the top number of your blood pressure. Your doctor will help you set and meet your blood pressure goal by prescribing medicine and suggesting lifestyle changes.10,11
If you have diabetes, it is also vital that you control your blood sugar levels.10,11
Many lifestyle changes that are good for controlling blood pressure and diabetes are also good for the kidneys. These include:10
- Take your medicines as prescribed.
- Avoid over-the-counter drugs that are hard on the kidneys, such as NSAID pain relievers.
- Work with a dietitian on a meal plan.
- Exercise 30 minutes a day on most days.
- Try to lose weight if you carry extra pounds.
- Get enough sleep.
- Stop smoking.
- Manage stress and depression.
- Cut back on salt in your diet.
Following all of these steps may seem overwhelming at first. But as you learn new habits, the goal is not to follow all of these steps every day. Try to do these things most days. Eventually, your new habits will become second nature.