What Are the Stages of Chronic Kidney Disease?

Understanding the Stages of Chronic Kidney Disease (CKD)

What Causes Chronic Kidney Disease (CKD)?

Chronic kidney disease (CKD) is a condition in which there is long-term damage to the kidneys that can gradually get worse over time. This is in contrast to other kidney diseases like acute kidney injury (AKI), in which there is a sudden decrease in kidney function, often caused by dehydration or an acute illness like an infection.

The most common causes of chronic kidney disease and chronic renal failure are high blood pressure and diabetes mellitus.

Any health conditions that can affect the kidneys can also lead to decreased kidney function and, eventually, chronic kidney disease. Examples include:

Diabetic nephropathy
Obstruction of the urinary tract (kidney stones, an enlarged prostate)
Drug toxicity
Autoimmune diseases (IgA nephropathy, lupus)
Polycystic kidney disease (a genetic disorder)
Renal artery stenosis

Glomerular diseases involve any conditions that damage the glomeruli, the filtering units of the kidneys, that work to remove waste and extra fluids from your blood. Examples include:

Glomerulonephritis (inflammation of the glomeruli)
Glomerulosclerosis (scarring of the glomeruli)

Older adults and people who are obese or smokers are at an increased risk of chronic kidney disease. In addition, certain medications can damage the kidneys, such as nonsteroidal anti-inflammatory drugs (pain relievers), certain cholesterol-lowering drugs, certain antibiotics, and others.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), an estimated 37 million Americans are living with chronic kidney disease.

What Are The Stages Of CKD?

Severe kidney damage and kidney failure do not develop overnight. CKD gradually progresses from very mild kidney damage to complete kidney failure. The stages of chronic kidney disease indicate the amount of kidney damage that has occurred.

CKD stages are numbered from low to high according to how well the kidneys are functioning to filter waste material and excess fluid out of the body. When a person has early-stage kidney disease (stages 1 and 2), the kidneys can perform this function quite well. In the more advanced stages of kidney disease (stages 3 and 4), the kidneys become less effective in eliminating waste.

Understanding the stages of chronic kidney disease helps to guide management. Doctors use CKD stages for risk stratification, disease progression, and anticipating and treating complications of CKD. This is because, in the advanced stages of chronic kidney disease, the damage to the kidneys can be severe enough that the kidneys stop working – this is called end-stage renal disease, stage 5 CKD, or kidney failure. People whose kidneys have failed need dialysis or a kidney transplant to survive. The stages of chronic kidney disease, therefore, help in the treatment planning and management of the condition.

Importance of eGFR In Determining Stages

A key metric that is used to determine how well the kidneys are working is called the estimated glomerular filtration rate or eGFR. This is a blood test that measures how much blood the kidneys filter every minute. The eGFR is calculated based on blood creatinine level, age, gender, race, and body weight. The stages of chronic kidney disease are based on the estimated glomerular filtration rate. As the kidney disease gets worse, the eGFR number goes down.

Creatinine is a waste product present in blood. It is formed from waste generated by muscles in the body. The level of creatinine in blood test results is called the serum creatinine level. The normal level of serum creatinine depends on a person’s age, gender, race, and body size. Serum creatinine is used to calculate eGFR, and eGFR is used to classify the stage of CKD.

A value called creatinine clearance refers to the amount of creatinine present in a 24-hour sample of urine. Creatinine clearance measures how well the kidneys are getting rid of this waste product.

Connection Between Kidney Disease, Heart Disease, and Diabetes

Chronic kidney disease, diabetes mellitus, and cardiovascular disease are closely linked and share some of the same risk factors, such as hypertension (high blood pressure).

In people with diabetes, high blood sugar levels can cause gradual damage to the kidneys, resulting in chronic kidney disease. The Centers for Disease Control and Prevention (CDC) estimates that about 1 in 3 adults living with diabetes (and 1 in 5 adults with high blood pressure) in the United States has chronic kidney disease.

When the kidneys are not working well, the heart has to work harder to pump blood to the kidneys. This can lead to heart disease. Cardiovascular mortality is a leading cause of death in the U.S.

Save On Your Medications and Maintain Your Kidney Health

What Are the 5 Stages of Chronic Kidney Disease?

Stage 1 CKD (eGFR of 90 or Greater)

Chronic kidney disease stage 1 is when the eGFR is 90 or greater. This means the percentage of kidney function is 90-100%. An eGFR of 90 or more means the kidneys are working well and kidney function is normal. However, there is mild kidney damage. Signs of kidney damage may include the presence of albuminuria (protein in the urine), which is an abnormal finding.

Signs and Symptoms

Most people with stage 1 CKD are asymptomatic patients (no symptoms). The condition is typically discovered on routine testing. When present, signs and symptoms may include:

High blood pressure
Swelling in the hands and feet
Frequent urinary tract infections
Hematuria blood in urine

Early Detection and Diagnosis

Stage 1 chronic kidney disease can be diagnosed with:

Blood tests such as estimated glomerular filtration rate (eGFR) and cystatin C
Urine tests such as albumin-creatinine ratio
Imaging tests (ultrasound, CT scan, MRI)
Kidney biopsy showing kidney damage

Management Strategies and Lifestyle Changes

To slow kidney damage, people with CKD stage 1 should:

Stay at a healthy body weight by eating a healthy, balanced diet and exercising regularly
Control their blood pressure and blood sugar levels by being adherent to their medication regimen and follow-up appointments with healthcare providers and lab works.
Avoid smoking.

People with stage 1 CKD may need to see a nephrologist (a kidney doctor) in addition to their primary care physician. The kidney doctor may prescribe medications to protect the kidneys.

Prognosis

The prognosis (outlook) for CKD stage 1 is good. Most people under the age of 50 with CKD stage 1 can expect to live 20 to 30 years or more if they follow their doctor’s treatment plan and lifestyle recommendations.

Stage 2 CKD (eGFR Between 60 and 89)

Indicators and CKD Progression from Stage 1

Stage 2 chronic kidney disease is when the eGFR is between 60 and 89, meaning the percentage of kidney function is 60-89%. This is a stage in which the kidneys are healthy and functioning well. However, there is mild kidney damage and mild loss of kidney function.

Signs and Symptoms and Laboratory Findings

Signs of kidney damage such as physical changes in the kidneys or protein in the urine can be present in people with stage 2 kidney disease. Generally speaking, the signs and symptoms of stage 2 CKD are similar to stage 1, except eGFR is between 60 and 89 in stage 2.

Treatment Options and Lifestyle Modifications

The ways of slowing CKD progression in patients with stage 2 CKD are the same as in stage 1 CKD (see above).

Stage 3 CKD (eGFR Between 30 and 59)

Definition

People with an eGFR between 30 and 59 are said to have stage 3 kidney disease. This means they have mild to severe kidney damage, and the kidneys are not working as well as they should. The percentage of kidney function is 30-59% compared to healthy individuals.

Distinction Between Stage 3A and Stage 3B

Stage 3 kidney disease is further classified into stages 3A and 3B.

Stage 3A indicates mild to moderate loss of kidney function with an eGFR between 45 and 59.
Stage 3B indicates moderate to severe loss of kidney function with an eGFR between 30 and 44.

Symptoms and Potential Complications

People with stage 3 kidney disease may or may not have symptoms. If symptoms are present, they may include:

Swelling in the hands and feet
Urinating more or less than normal
Foamy or dark-colored urine
Weakness
Tiredness
Dry, itchy skin
Back pain
Muscle cramps
Sleep problems
Restless legs syndrome (RLS)

Because the kidneys are not working as well as they should, people with stage 3 kidney disease can develop additional health complications due to the build-up of waste and extra fluid in the body. Problems can include anemia, high blood pressure, and bone disease.

Managing Symptoms and Slowing Progression

It is important for stage 3 CKD patients to eat a healthy diet, be physically active, and maintain a healthy weight. If you have stage 3 CKD, your doctor may suggest meeting with a dietician to work on a healthy diet plan. You will also be asked to see a nephrologist (kidney doctor) at regular intervals to monitor your kidney health and kidney function.

Treatment

The treatment for stage 3 kidney disease is designed to slow the progression of kidney disease. This includes controlling blood pressure and blood sugar levels, with medications if necessary.

As for stages 1 and 2, the nephrologist will identify the causes of the chronic kidney disease and treat them if they are reversible. Drugs like angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are prescribed to control blood pressure. Diabetes medications are prescribed to control blood glucose levels. Patients are also counseled on the importance of smoking cessation, protein restriction in the diet, and strict blood glucose control.

Prognosis and Renal Outcomes

Life expectancy for people with stage 3 chronic kidney disease ranges from 10 to 20 years or more for a 50-year-old patient with proper management.

Stage 4 CKD (eGFR Between 15 and 29)

Definition

When the eGFR is between 15 and 29, it is classified as stage 4 kidney disease. In people with stage 4 CKD, the kidneys are moderately to severely damaged and there is severe loss of kidney function. The percentage of kidney function is between 15 and 29% compared to healthy people. This is the last stage of kidney disease before progression to kidney failure.

Signs and Symptoms

People with CKD stage 4 are more likely to have symptoms than the early stages of chronic kidney disease. These may include:

Weakness
Tiredness
Swelling in the hands and feet
Urinating more or less than normal
Lower back pain
Muscle cramps
Nausea
Loss of appetite

Progression and Medical Complications

In people with stage 4 CKD, the kidneys are moderately to severely damaged and do not filter waste from the blood like they should. This can lead to buildup of waste products in the body and cause other health problems, such as:

Hypertension (high blood pressure)
Anemia (low numbers of red blood cells in the body)
Cardiovascular disease
Pulmonary edema (fluid buildup in the lungs)
Bone disease
Hyperkalemia (high blood potassium levels)
Hyperphosphatemia (high blood phosphorus levels)
Metabolic acidosis (acid buildup)

Preparing For Potential Dialysis or Transplant

If you have late-stage kidney disease, your nephrologist will start talking to you about preparing for kidney failure, i.e., starting dialysis or planning for a kidney transplant.

Stage 5 CKD (eGFR Less Than 15)

Definition of End-Stage Renal Disease (ESRD) and Kidney Failure

An eGFR of less than 15 is classified as stage 5 kidney disease or end-stage renal disease. It indicates that the kidneys have failed.

Signs and Symptoms

The build-up of waste in the bodies of patients with stage 5 CKD can lead to various symptoms such as muscle cramps, itching, nausea, vomiting, loss of appetite, swelling in the hands and feet, trouble breathing, problems sleeping, urinating more or less than normal, and back pain.

Treatment Options: Dialysis and Kidney Transplantation

Once the kidneys have failed, a person needs either dialysis or a kidney transplant to survive. The treatment at stage 5 CKD also includes treating any complications that arise.

Dialysis

Dialysis is a procedure that does the work of the kidneys in chronic kidney disease patients. It is a type of renal replacement therapy that removes waste products from the blood when the kidneys have failed. There are different types of dialysis with varying impacts on daily life.

During hemodialysis, the blood is transported through tubes into a machine where it is cleaned by a filter called the dialyzer. The clean blood is then put back into the body through tubes. Hemodialysis can be done at a medical center or home with a home dialysis machine.

The other type of dialysis is called peritoneal dialysis. It involves cleaning the blood using the peritoneum (inner lining of the abdomen or belly) and a cleaning solution called dialysate. People with end-stage kidney disease can do peritoneal dialysis at home or work in a clean area.

Kidney Transplant

Kidney transplantation is a surgery in which a healthy kidney is transplanted from a donor’s body into the body of a patient with kidney failure. The donor can be a living donor who donates one of their two healthy kidneys or a deceased donor. You can have a kidney transplant when your kidneys are close to failing and avoid starting dialysis.

Living With CKD: Patient Education and Support Systems

If you have end-stage kidney disease, you can benefit from various support systems, including:

Peer support groups to connect with others who understand what you’re going through and share resources for treatment options. A nephrologist, nurse practitioner, or social worker can refer you to a support group.
Lifestyle education to learn about a kidney-friendly diet, exercise, and other lifestyle modifications.
Consultations with allied health care professionals such as referrals to dietitians, social workers, mental health professionals, physical therapists, and occupational therapists.
Home care services to provide clinical and social support and help with dialysis.

Common Questions

How to Prevent Chronic Kidney Disease?

Eating a healthy diet, getting regular exercise, maintaining a healthy body weight, and keeping blood pressure and blood sugar levels in check are the best ways to prevent kidney disease.

What Is The Life Expectancy With Chronic Kidney Disease?

The life expectancy with chronic kidney disease depends on the stage of CKD, the person’s age and gender, other health conditions, and other factors such as how well a person follows the prescribed treatment plan and lifestyle measures. Your kidney specialist can give you an idea of what to expect in terms of life expectancy taking in account all these factors.

For example, the average life expectancy with stage 2 chronic kidney disease is 39 years for a 30-year-old male and 44 years for a 30-year-old female. For stage 4 chronic kidney, the average life expectancy is 15 years for a 30-year-old male and 3 years for a 75-year-old male.

According to the National Kidney Foundation, the average life expectancy of dialysis patients is 5 to 10 years, but some people with end-stage kidney disease have lived for 20-30 years on dialysis.