The kidneys are a pair of organs located in the middle of the back, just below the rib cage. Their function is to filter the blood, by removing toxins and waste products. When the kidneys are not functioning, these waste products can build up in the body, leading to a variety of symptoms.
The leading cause of kidney disease in the US is diabetes, followed by high blood pressure. It’s important to know the chronic kidney disease facts, so you can help to protect yourself from the long-term effects of this common disease.
What is Chronic Kidney Disease?
Chronic kidney disease, or CKD, occurs when the kidneys slowly lose their ability to function. When this happens, they gradually become unable to filter waste products and toxins from the blood. These build up in the blood and cause damage around the body, leading to the long-term effects of chronic kidney disease.
Causes of Chronic Kidney Disease
The most common cause of CKD is diabetes. Both type 1 and type 2 diabetes can damage the kidneys over time, because high blood sugar levels affect the very small blood vessels of the kidneys. Another common cause of kidney disease is hypertension, or high blood pressure. Both diabetes and high blood pressure are extremely common among adults in the US, and many people have both of these conditions.
Chronic Kidney Disease Risk Factors
Because diabetes is the leading cause of kidney disease, people who have diabetes are at the greatest risk. Those who have high blood pressure, which is also an extremely common cause of chronic kidney disease, are also at significant risk. Being significantly overweight increases a person’s risk for both of these conditions, and is a risk factor for developing chronic kidney disease.
Additional risk factors include:
- Age, with older people being at greater risk
- Race, with African-Americans being at the highest risk
- Gender, with men being more likely to experience severe chronic kidney disease
- Family history of kidney disease
- Smoking, which increases the risk
- Heavy alcohol use, which increases the risk
Stages of Kidney Disease
There are five stages of chronic kidney disease. These are based on the estimated glomerular filtration rate, or eGFR. The eGFR is calculated based on a blood test, which measures a waste product that’s normally filtered out by the kidneys. The stages of kidney disease are:
- Stage 1: eGFR 90 or higher
- Stage 2: eGFR 60 to 89
- Stage 3a: eGFR 45 to 59
- Stage 3b: eGFR 30 to 44
- Stage 4: eGFR 15 to 29
- Stage 5: eGFR less than 15
For people with chronic kidney disease, information provided by tests like the eGFR is important in order to determine whether it’s progressing into more advanced kidney disease.
How is kidney disease diagnosed?
The diagnosis of kidney disease requires testing. In most cases, blood and urine tests are used to check for abnormal kidney function. If kidney disease is found, then additional tests may be needed to find the cause of the problem. Further blood and urine tests, as well as imaging tests like an ultrasound, might be used. In certain cases, a biopsy is needed; this is a small sample of tissue that a pathologist can examine under a microscope to check for abnormalities. The specific tests that are needed will vary depending on the specific medical situation.
Chronic Kidney Disease Signs and Symptoms
People with chronic kidney disease may display a variety of symptoms, including:
- Loss of appetite
- Fatigue and low energy
- Swelling in the feet and hands
- Anemia (low red blood cell count)
- Muscle cramps
- Itchy skin
- Frequent urination
How do you know if you have chronic kidney disease?
Although there may be a suspicion of chronic kidney disease based on having chronic kidney disease symptoms and risk factors, the only way to be sure about kidney disease is to get your kidney function tested. For people who have significant risk factors, it’s often recommended to test regularly, in order to detect kidney disease as early as possible.
One option is to visit your doctor to discuss your symptoms and concerns, and they will order the tests that you need. You’ll then go to a laboratory to get your test.
Another option is to get a home test kit. This is mailed to your home. You then mail back a urine sample, and/or a blood sample obtained through a fingerprick. You’ll get your results online, and you’ll have the opportunity to talk to a licensed healthcare provider to discuss what to do next if your results show abnormal kidney function. This may be a more convenient option for many people.
Chronic Kidney Disease Basics. Centers for Disease Control and Prevention. https://www.cdc.gov/kidneydisease/basics.html. Accessed 13 June 2022.
Chronic Kidney Disease (CKD). National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/kidney-disease/chronic-kidney-disease-ckd. Accessed 13 June 2022.
Chronic kidney disease. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/chronic-kidney-disease/symptoms-causes/syc-20354521. Accessed 13 June 2022.
Kazancioglu R. Risk factors for chronic kidney disease: an update. Kidney Int Suppl (2011). 2013 Dec; 3(4): 368–371. doi: 10.1038/kisup.2013.79