Stages 1–5 of Kidney Disease: What They Mean (2024)

CKD Stages 1 Through 5 Based on eGFR

In the early stages of CKD (stages 1 to 3), your kidneys are still largely functional. In the later stages (stages 4 and 5), your kidneys have to work harder to filter blood and may stop working altogether.

The staging of CKD is important because it informs the treatment plan and directs which measures should be used based on the eGFR calculation and the rate by which the eGFR declines over time.

Stage 1 CKD

With stage 1 CKD, the damage to your kidneys is mild. Because of this, you may not have symptoms.

You will invariably have an increased amount of protein in your urine (proteinuria). This is because damaged glomeruli allow more protein to escape into your urine rather than being filtered and returned to the bloodstream.

Typically, there are no symptoms associated with stage 1 CKD. While certain changes may be seen on ultrasound or in urine tests, they may not cause observable symptoms. The one exception is foamy urine caused by excessive amounts of a protein called albumin in your urine.

Treatment at stage 1 is largely focused on managing the underlying cause of kidney damage to slow disease progression.

This may include:

• Keeping your blood pressure in a healthy range (under 120/80 millimeters of mercury, or mm Hg), in part by limiting your salt (sodium) intake to less than 2,300 milligrams (mg) per day
• Controlling your blood glucose (sugar) if you have diabetes

Stage 2 CKD

With stage 2 CKD, the damage to your kidneys is still mild, but the kidneys are starting to function at less than their optimal capacity. As symptoms generally do not start until stage 3, many people with stage 2 CKD may not know they have kidney disease.

If symptoms do occur, they may again involve foamy urine and/or an increased risk of urinary tract infections (UTIs), especially in females.

With stage 2 CKD, your healthcare provider may recommend certain lifestyle changes in addition to managing your blood pressure and diabetes.

These may include:

• Losing weight with a healthy diet and routine exercise if you are overweight or have obesity
• Quitting cigarettes, which can lower blood pressure and reduce stress on the kidneys
• Getting plenty of sleep and managing stress, both of which also influence blood pressure
• Starting diabetes or blood pressure medications such as angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), sodium-glucose co-transporter 2 (SGLT2) inhibitors, orKerendia(finerenone) which can slow or stop CKD progression

Stage 3 CKD

Stage 3 CKD is when your kidneys sustain significant enough damage to start producing symptoms. There are two substages. Stage 3a is kidney function loss that's mild to moderate. Stage 3b is kidney function loss that's moderate to severe.

Increasing damage to the kidneys can cause the loss of important nutrients like calcium and vitamin D, affecting bone health. It can also cause a buildup of acid in your blood (metabolic acidosis) and a decrease in red blood cells (anemia).

Symptoms of stage 3a CKD may include:

• Urinating more often or less often than usual
• Fatigue and tiredness
• Dry and/or itchy skin
• Nausea
• Loss of appetite
• Unintended weight loss

With stage 3b, a person may additionally experience:

• Trouble concentrating
  
• Muscle aches or cramps
• Shortness of breath
• Peripheral neuropathy (numbness or prickly sensations in the hands or feet)
• Peripheral edema (swelling in the arms, legs, hands, or feet)

With stage 3 CKD, additional interventions will likely be needed to control blood pressure and/or blood sugar while reducing the risk of disease complications.

These may include:

• Taking a statin drugto reduce cholesterol
• Taking a diuretic to promote urination, reduce blood pressure, and reduce peripheral edema
• Taking calcium and vitamin D supplements to keep your bones strong
• Taking iron supplements to help manage anemia

Stage 4 CKD

Stage 4 CKD means that your kidneys are moderately to severely damaged, increasing the likelihood of disease complications like anemia, high blood pressure, bone disease, and metabolic acidosis.

The damage can also cause the excessive buildup of potassium (hyperkalemia) and phosphorus (hyperphosphatemia) in your blood, both of which can contribute to heart rhythm disorders and an increased risk of heart disease or stroke.

In addition to an increased risk of the above-listed symptoms, stage 4 CKD can also cause:

• Persistent lower back pain
• Insomnia (trouble sleeping)
• Breath that smells fishy or like ammonia or urine
• Hematuria (blood in the urine)

Additional aggressive treatments will be started to preserve what kidney function you have.

These include:

• Changing your diet to restrict how much protein, phosphorus, and potassium you consume
• Adjusting or avoiding medications that stress the kidneys, including statins, insulin, antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and proton pump inhibitors (PPIs)
• Taking erythropoiesis-stimulating agents (ESAs) to treat severe anemia

Treating stage 4 CKD can be challenging because many of the medications you take to manage high blood pressure and diabetes can suddenly place stress on the kidneys and promote kidney damage.

Stage 5 CKD

Stage 5 is the most advanced stage of CKD, in which you experience kidney failure. Also known as end-stage renal failure (ESRD), stage 5 CKD is when your kidneys are no longer functional enough to support your body's needs.

Stage 5 CKD is associated with uremia, a potentially dangerous condition in which waste products build up in your blood.

This can lead to potentially severe symptoms like:

• Dyspnea (shortness of breath)
• Pruritus (itchiness), often severe
• Chest pain or pressure
• Vomiting or diarrhea
• Restless legs syndrome
• Vomiting or diarrhea
• Abnormal bruising
• Personality changes
• Psychosis
• Seizures
  

At this stage of the disease, the only options for treatment are:

• Dialysis, either in the form of hemodialysis (using a machine to filter your blood) or peritoneal dialysis (using the lining of your abdominal cavity to filter your blood)
• Kidney transplantation, either from a living donor or a recently deceased donor

In the absence of treatment, death will eventually occur, However, the time of progression to death is variable.

CKD Stages Progression

Chronic kidney disease usually progresses slowly over the course of years. Even so, many people do not realize that they have the disease until it is advanced and symptoms are severe enough to seek treatment. Of theestimated 37 million adults living with CKD in the United States, 1 in 9 people are unaware that they have the disease.

Even so, the progression of CKD can be slowed or even stopped if the disease is diagnosed and treated early. With the appropriate treatment and healthy life changes, many people with stage 1, 2, or 3 CKDwill never progress tostage 4 or 5.

This is evidenced by a 2021 study in the Clinical Kidney Journal. It showed that, of the 88,766 people with CKD and diabetes, only 5% to 8.4% showed any signs of progression over three years. The rapid progression of CKD—defined as a progression over two CKD stages within four years—is even less common, affecting only 2% of the study population.

Among the factors that can increase the risk of CKD progression are:

• A sustained decline in eGFR
• A decline in eGFR of 25% or greater from the baseline result
• Having uncontrolled high blood pressure
• Having kidney disorders like polycystic kidney disease (PKD) or glomerulonephritis
• Having chronic metabolic acidosis
• Being a current smoker
• Having a lower body mass index (BMI)

Being over 70 is also a factor, given that aging is associated with a natural decline in kidney function and the progression of chronic diseases like diabetes.

Effect of CKD on Life Expectancy

Chronic kidney disease is one of the leading causes of mortality (death) worldwide and one of the few noncommunicable diseases (those not passed to others through contact) in which annual deaths worldwide have increased over the past two decades.

In the United States, deaths from CKD are mainly due to heart disease,

CKD and heart disease often co-occur as they share many of the same risk factors, including high blood pressure, diabetes, and older age. Nearly one-third of the 1,938,505 deaths reported in people with CKD in the United States from 1999 to 2020 were due to heart disease.

Based on a 2023 review of studies involving 210,748 adults in the United States, CKD independently increases the risk of death from heart disease by more than threefold.

Other common causes of death in people with CKD include:

• Septicemia
• Viral hepatitis
• Lung disease
• Kidney cancer
• Complications of diabetes

Follow-Up and Monitoring CKD Stages

If you are diagnosed with CKD, it is essential to monitor your eGFR and other kidney function tests regularly. Depending on your CKD stage, this may involve testing at least once annually. If and when CKD progresses, more frequent testing may be needed.

The testing should involve the following blood and urine tests:

• EGFR
• Serum creatinine
• Urine albumin
• Urine albumin-to-creatinine ratio (UACR)

Routine testing may be recommended every four to six months if albumin levels are high and/or you have stage 3 CKD or higher.

Some health experts recommend testing every two months for people with stage 4 CKD and every month for those with stage 5 CKD.

Summary

Chronic kidney disease has five stages. Stages 1 through 3 are often asymptomatic. Symptoms more often become apparent by stage 4. By stage 5, you are said to have end-stage renal disease (ESRD), in which you need either dialysis or a kidney transplant to survive.

The five stages of CKD are determined by the results of an EGFR test. The test estimates how much blood is filtered through your kidneys every minute.