The 5 stages of chronic kidney disease
Your kidneys filter your blood by removing waste and extra water to make urine. The glomerular filtration rate (GFR) shows how well the kidneys are filtering. An estimated 37 million adults in the United States may have chronic kidney disease (CKD) but nearly 90% are unaware of their condition. When found early, people can take important steps to protect their kidneys.
DIAGNOSIS
Kidney function tests are urine or blood tests that evaluate how well your kidneys are working. Most of these tests measure glomerular filtration rate (GFR). GFR assesses how efficiently your kidneys clear waste from your system.
Here are three signs that could indicate that you are beginning to experience a decline in kidney function.
Dizziness and Fatigue. One of the first possible signs of weakening kidneys is the experience of overall weakness in yourself and your overall health. …
Swelling (Edema) …
Changes in urination.
The best measure of kidney function is the glomerular filtration rate (GFR). Measuring GFR is complicated in clinical practice, requiring substantial time and resources. Alternatively, GFR can be estimated from a blood sample by using equations (eGFR) based on the plasma concentration of creatinine or cystatin C.
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- Blood test: eGFR.
- Blood test: Serum creatinine test.
- Blood urea nitrogen (BUN) test.
- Urine test
- Kidney ultrasound.
- Kidney biopsy.
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CT and MRI Contrast and Kidney Function
CT contrast materials do rarely cause kidney damage and a skin disorder called nephrogenic systemic fibrosis (NSF) can be caused by the MRI contrast agents. Patients with poor kidney function are the people at risk for these side effects.
We know that most patients have normal kidney function and need no precautions, however, not every patient with impaired kidney function will be aware of it. We know that the likelihood of impaired renal function is substantially higher in some people, such as patients over 60 years old and those who have certain illnesses, such as diabetes.
Historically serum creatinine was the lab value used to assess kidney function. A better and more accurate measure is a lab result called estimated glomerular filtration rate (eGFR). eGFR takes into account the serum creatinine value and also patient age, race, and gender which affect kidney function results.
This very accurate blood test assesses kidney function and it can be obtained quickly, right before a scan. For CT, eGFR > 45 indicates no increased risk of kidney damage from contrast material. eGFR > 30, but less than 45 indicates that while it is safe to get contrast material, there is a small risk of causing kidney damage. In that situation, we will inject additional fluid into the patient’s vein before and after the contrast material injection. This hydration is effective to prevent any renal damage. For MRI, it is safe to give a regular dose of contrast material as long as the patient’s eGFR is > 30.
For both MRI and CT contrast agents, once injected they are cleared from your body by your kidneys. If your kidney function is below normal then two things happen. First, the contrast agents are cleared more slowly from your body. If kidney function is very poor (eGFR < 30) this prolonged exposure can lead to a change in the injected MRI agent’s chemical composition and create a small risk of developing NSF. For MRI contrast agents there is no risk of developing the skin disease of concern if the eGFR is >30. For CT contrast materials, where a larger volume of the contrast agent is used than for MRI, the functioning kidney is exposed to contrast material for a longer time than in people who have completely normal kidneys and can clear it more rapidly. This prolonged exposure is thought to increase the risk of developing kidney damage. The risk is very low, about 1% unless the patient’s eGFR is < 30, then the risk goes up slightly. Even when kidney damage occurs, it is almost always temporary and will resolve without treatment.
In many cases, the color of a person’s urine can indicate whether or not they are drinking enough water. Clear urine often indicates proper hydration.
In some cases of clear urine, however, a person may be too hydrated or have an underlying condition that causes them to urinate more than usual.
If a person has consumed a lot of liquids during the day, they may have too much water in their system.
When this occurs, they can inadvertently dilute their blood and lower their essential salt and electrolyte levels.
In some rare cases, a person may develop hyponatremia. Hyponatremia is a potentially life-threatening condition in which the brain swells due to a lack of salt in the body.
According to researchTrusted Source from 2014, hyponatremia can occur due to excessive water intake or because the kidneys are not processing water fast enough.
If a person has clear urine occasionally, it is most likely that they are very well hydrated on those days.
However, a person may wish to speak to a doctor if they have consistently clear urine, as it may indicate an underlying condition, such as:
Diabetes occurs when the body cannot regulate blood sugar (glucose) levels and therefore cannot use the sugar properly for energy.
People with diabetes often have excessive thirst and feel the need to urinate frequently. The excess urination is from the kidneys trying to get rid of extra sugar and liquid.
Without treatment, diabetes can be life-threatening. However, a doctor can easily diagnose it with a blood test, and there are many treatment options.
Learn more about the symptoms of diabetes here.
Diabetes insipidus is a rare condition that occurs when the kidneys produce an unusually high amount of urine.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, most people pass around 1–2 quartsTrusted Source of urine per day. A person with diabetes insipidus passes about 3–20 quarts of urine each day.
People living with diabetes insipidus do not have issues with their blood sugar levels like those with more common types of diabetes.
Instead, their kidneys cannot balance fluids properly, and their body may make them feel more thirsty than normal to help replace lost fluids.
Underlying kidney problems
If the kidneys are damaged or infected, a person can experience abnormal urination, including clear urination.
They may also have other symptoms, such as painful urination or a fever.
A set of rare conditions known as Bartter syndrome, or potassium wasting, can also cause a person to urinate frequently. If they drink more to compensate, their urine may be clear.
Taking diuretics is another possible cause of clear urine. These medications cause the body to produce more urine to flush out extra salts and water.
If a person is taking diuretics, it can cause excessive urination that may be very pale or clear.
Pregnant women may also develop a form of diabetes called gestational diabetes. The symptoms may be mild but include increased thirst and needing to urinate more often.
Gestational diabetes can increase the risk of pregnancy complications, so a doctor may test for it during a regular checkup. It usually disappears after childbirth.
Learn more about the symptoms of gestational diabetes here.
Other colors
Urine can vary in color depending on the person and their diet. In many people, urine color may indicate the level of hydration, foods eaten or medications taken, or the presence of an underlying health condition.
5 STAGES OF CHRONIC KIDNEY DISEASE (CKD)
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- Stage 1 with normal or high GFR (GFR > 90 mL/min)
- Stage 2 Mild CKD (GFR = 60-89 mL/min)
- Stage 3A Moderate CKD (GFR = 45-59 mL/min)
- Stage 3B Moderate CKD (GFR = 30-44 mL/min)
- Stage 4 Severe CKD (GFR = 15-29 mL/min)
- Stage 5 End Stage CKD (GFR <15 mL/min)
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There are 5 stages of CKD, from very mild damage in stage 1 to complete kidney failure in stage 5, which is end-stage kidney disease (ESKD). An eGFR kidney function test is used to determine the exact stage of CKD. In the early stages, your kidneys are still able to filter out waste from your blood. In the later stages, your kidneys must work harder to get rid of waste and may stop working altogether.
CKD is a progressive disease, which means that kidney function declines over time. There are generally no symptoms of chronic kidney disease until you reach the later stages. Once you experience symptoms of CKD, the disease is usually in an advanced stage, and in some cases, you may be close to needing kidney dialysis or a transplant.
How do I find out if I have kidney disease?
What level of creatinine indicates kidney failure?
| Age (years) | Average eGFR |
|---|---|
| 30–39 | 107 |
| 40–49 | 99 |
| 50–59 | 93 |
| 60–69 | 85 |
| 70+ | 75 |
Chronic kidney disease, or CKD, is diagnosed in stages ranging from 1 to 5, measured by levels of a waste product in the blood called creatine. Doctors make a prognosis by evaluating the stage of the disease along with an individual’s general health and age. Stage 1 and 2 kidney disease indicates mild damage when your kidneys are mostly healthy and still working well. Stages 3, 4, and 5 reflect a more serious progression of CKD, with different life expectancies. Kidney disease is a serious health matter, but there are effective treatments and lifestyle practices that can slow its progression. A kidney transplant can give some people a normal life expectancy.
Later Stages of Kidney Disease: Stages 3, 4 and 5
Many people with CKD aren’t diagnosed till the disease has advanced, as symptoms often don’t appear till kidney function is at 25% or less. CKD is a progressive disease that worsens slowly over a period of years and leads to kidney failure. With kidney failure, waste products must be cleaned out of your blood by mechanical means. Here are the life expectancies for later stages of chronic kidney disease, though individual experiences and life spans vary widely:
- Stage 3 Kidney Disease: You may not have symptoms, but your creatine levels indicate some damage to your kidneys. At this relatively early stage, you do not need dialysis or a kidney transplant. Life expectancy for stage 3 kidney disease differs between men and women. A 40-year-old man has a typical life expectancy of 24 years after diagnosis, and a 40-year-old woman with the same diagnosis has a life expectancy of 28 years.
- Stage 4 Kidney Disease: The kidneys are significantly damaged. Kidney failure becomes likely, which will require dialysis or a kidney transplant. A 40-year-old man with stage 4 kidney disease has a life expectancy of 14 years after diagnosis, while a 40-year-old woman can expect to live 16 more years. The right diet and medication may still slow disease progression.
- Stage 5 Kidney Disease: The kidneys are close to failure or have failed. You need to start dialysis or, if you are a candidate, have a kidney transplant. There are not enough donor kidneys available for everyone to get a transplant. Without a transplant, men between the ages of 30 to 35 have a life expectancy of 14 years with stage 5 CKD. For women of the same age, the expected life span is 13 years. If you are between 70 and 75 years, life expectancy is 4 years for both men and women. If you have a successful transplant, you can live a normal life span. Even without dialysis or a transplant, your life expectancy may be improved by taking medication and following a healthy lifestyle.
Symptoms of kidney disease
Kidney disease usually gets worse slowly, and symptoms may not appear until your kidneys are badly damaged. In the late stages of kidney disease, as you are nearing kidney failure, you may notice symptoms that are caused by waste and extra fluid building up in your body.
You may have one or more of these symptoms if your kidneys are beginning to fail:
Steps you can take to slow the progression of chronic kidney disease
There isn’t a cure for CKD. Once your kidneys are damaged, they can’t be repaired, so it’s important to do everything you can to keep your disease from progressing and causing further damage. By catching it early and managing your medical conditions, along with nutritional and lifestyle changes, you may be able to slow the progression of CKD.
Control your blood sugar. Achieving and maintaining optimal blood sugar control may help slow the progression of CKD.
Control your blood pressure. High blood pressure is both a cause and complication of CKD. Controlling blood pressure is one of the most effective things you can do to slow the progression of CKD.
Manage your diet by following a kidney-friendly meal plan.
Don’t smoke. Cigarette smoking is associated with the progression of CKD. Smoking also contributes to death from stroke and heart attack in people with CKD. If you do smoke, talk to your doctor about how to quit.
Exercise at least 30 minutes a day, most days of the week. A combination of aerobic conditioning such as walking, biking, or jogging, along with strength training, is ideal. Physical activity may help prevent heart disease, improve glucose control in those with diabetes, and maintain muscle mass.
Maintain a healthy weight. Being overweight is linked to high blood pressure, heart disease, and CKD.
Avoid overuse of nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, which can damage kidneys.
Take medication as prescribed by your healthcare provider.
Schedule regular checkups with your doctor to monitor your kidney function.
Consider seeing a nephrologist, a doctor who specializes in kidney diseases. Much like you see an ophthalmologist for your eyes, you may want to talk with a nephrologist about your kidney health.
Kidney-friendly meal plan
It may surprise you to learn that some of the foods you eat as part of a healthy diet for type 2 diabetes are not necessarily good for your kidneys if you have chronic kidney disease. A kidney-friendly meal plan helps protect your kidneys from further damage and limits the amount of potassium and phosphorus you consume, as well as fluids you drink. This can help keep waste and fluid from building up and causing problems. Be sure to talk with a dietitian about what is the best meal plan for you.
Limit potassium, phosphorus, and water
Potassium is a mineral found in foods such as bananas, potatoes, and spinach. When you have CKD in T2D, your potassium levels may be too high, so you may need to limit or avoid certain foods. Your doctor may have you take a medicine called a potassium binder to help your body get rid of extra potassium.
Phosphorus is a mineral found in foods such as oatmeal, whole-grain bread, and nuts. When your kidneys aren’t working well, phosphorus can build up in your blood, leading to weak bones that easily break. Depending on your stage of CKD, your doctor may prescribe a medicine called a phosphate binder.
You may not need as much water because damaged kidneys do not get rid of extra fluid as well as they should. Too much fluid in your body can cause high blood pressure, swelling, and heart failure. Extra fluid can also build up around the lungs and make it hard to breathe. Based on your stage of CKD, your doctor may tell you to limit fluids.
General dietary guidelines
Staying at a healthy weight and eating a balanced diet that is low in salt and fat can help you control your blood pressure, and keep you healthy and feeling well. Here are some helpful dietary considerations to keep in mind. Always talk to your doctor before making changes to your diet.
Reduce sodium. Choose and prepare foods with less sodium to help control blood pressure. Aim for no more than 2300 mg of sodium daily.
Talk with a dietitian about what types of protein to include in your diet. Some doctors recommend that people with CKD limit protein or change their source of protein. A diet very high in protein can make the kidneys work harder and may cause more damage.
- Lower-protein foods include bread, fruits, vegetables, pasta, and rice
- Higher-protein foods include red meat, poultry, fish, and eggs
Choose heart-healthy foods. Grill, broil, bake, roast, or stir-fry foods, instead of deep-frying them. Limit saturated and trans fats (found in margarine, microwave popcorn, fried foods, and some baked goods).
Limit alcohol to 1 drink a day for women and 2 for men. Excessive drinking can affect your health and worsen CKD.
Kidney dialysis
Kidney dialysis helps clean your blood when you reach end-stage kidney disease and your kidneys no longer function. There are 2 types, hemodialysis, and peritoneal dialysis.
What is hemodialysis?
Hemodialysis is a treatment that uses a machine to filter waste and water from your blood. Hemodialysis also helps control blood pressure and balance important minerals in your blood, such as potassium, sodium, and calcium. The procedure is done at a dialysis center or at home. Each hemodialysis treatment lasts about 3 to 4 hours and is done 3 times a week.
What is peritoneal dialysis?
Peritoneal dialysis cleans your blood by using the lining of your abdomen, called the peritoneum, and a cleaning solution called dialysate. The abdominal area is filled with a cleaning fluid called dialysate. The dialysate uses the lining that covers most of the organs in your belly to serve as a filter for the dialysis process. Peritoneal dialysis is done 7 days a week at home manually or with the help of a machine called a cycler.
Read more about peritoneal dialysis
Kidney transplant
A kidney transplant is a surgery to give you a healthy kidney from someone else’s body. A kidney transplant may come from a live donor (usually someone you know) or from a deceased donor. A healthy kidney can do the job that your kidneys did when they were healthy.
The United Network for Organ Sharing (UNOS) keeps track of all the people in the United States who need kidney transplants and matches them with donors. The average wait time for a kidney from the national deceased donor waiting list in the United States is 5 years.
Conclusion
The five stages of CKD refer to how well your kidneys are working. Kidney disease can get worse in time. In the early stages (Stages 1–3), your kidneys are still able to filter waste out of your blood. In the later stages (Stages 4–5), your kidneys must work harder to filter your blood and may stop working altogether.
The goal at each stage of CKD is to take steps to slow down the damage to your kidneys and keep your kidneys working as long as possible.
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