Kidney Disease Education
An overview of Chronic Kidney Disease (CKD), including what it is, its symptoms, causes, risk factors, key clinical indicators, and its impact on overall health and body systems. Talk to your doctor if you think you are at risk.
Understanding Chronic Kidney Disease (CKD)
Chronic Kidney Disease (CKD) affects at least 13% of people in North America, with over 26 million Americans — about one in nine adults — at risk, many without knowing it.¹ ²
CKD occurs when the kidneys can no longer properly filter waste from the blood. As these wastes build up, they can lead to serious complications such as high blood pressure, anemia, weak bones, poor nutrition, and nerve damage — and can become life-threatening if untreated.³
Because early-stage CKD often has no noticeable symptoms, it frequently goes undetected. However, it is a progressive disease, meaning it worsens over time. Early detection and treatment are essential to slowing its progression and reducing complications.²
CKD: One in Nine Adults at Increased Risk
According to the National Kidney Foundation, more than 26 million Americans — one in nine adults — are at increased risk, and most don’t know it. Kidney disease can be found and treated early to prevent its progression and complications.
That’s because, in the early stages, there are rarely any symptoms, or the symptoms are too slight to notice. However, CKD is a degenerative disease, which means that over time, the condition will worsen.
The Global Burden of Chronic Kidney Disease (CKD)
Chronic Kidney Disease (CKD) is a major global health challenge. Diseases of the kidney and urinary tract cause approximately 850,000 deaths each year, with CKD ranking as the 12th leading cause of death and the 17th leading cause of disability worldwide.⁴ The true burden is likely higher. Patients with CKD are at significantly increased risk of cardiovascular disease and are more likely to die from heart attack or stroke than from kidney failure itself. At the same time, cardiovascular patients are at elevated risk for CKD, which often goes unrecognized due to overlapping symptoms.
More than 300 million people worldwide are estimated to have CKD.⁵ Yet access to treatments such as dialysis and transplantation remains limited in many regions, and early-stage disease frequently goes undetected.
These factors highlight a substantial unmet need for earlier detection and improved management.
Five Stages of Chronic Kidney Disease (CKD)
In the five stages of kidney disease, each stage is progressively more serious. Kidney disease advances from Stage 1 to Stage 5 as determined by a test called the GFR or glomerular filtration rate. GFR is an indicator of how well the kidneys are filtering the blood.
Three Main Indicators of Kidney Disease
What is Creatinine?
Creatinine is a natural waste product produced when muscles use energy. Because this is a continuous process, blood creatinine levels are a reliable marker of kidney function.
When kidney filtration slows, creatinine accumulates in the bloodstream, signaling potential kidney stress or reduced kidney function.
Understanding Creatinine Numbers
Levels can rise temporarily from dehydration, intense exercise, certain medications, or other factors, and may return to normal.
However, when creatinine levels stay high, it can signal that the kidneys aren’t filtering waste effectively. Monitoring creatinine over time helps identify potential kidney issues early and guide next steps in care.
What is BUN?
BUN (Blood Urea Nitrogen) measures the amount of urea in the blood, a waste product formed when the body breaks down protein. Healthy kidneys filter urea efficiently, so BUN levels are a key indicator of kidney function.
Understanding High and Low BUN Levels
Levels can rise temporarily from dehydration, a high-protein diet, certain medications, or other factors, and may return to normal once the cause is addressed.
Consistently high BUN levels, however, can indicate that the kidneys are under stress or not filtering waste efficiently. Low BUN levels can sometimes point to malnutrition, liver issues, or overhydration.
What is eGFR?
eGFR (estimated Glomerular Filtration Rate) measures how efficiently the kidneys filter waste from the blood. Rather than a single lab value, eGFR estimates overall kidney function using markers such as creatinine, cystatin C, age, sex, and sometimes race.
- Higher eGFR → better kidney filtration
- Lower eGFR → reduced kidney function and potential accumulation of waste in the blood
eGFR variations can be influenced by factors such as muscle mass, medications, and other health conditions. Monitoring eGFR is critical for early detection of kidney stress, chronic kidney disease, or declining renal function.
General Symptoms of Chronic Kidney Disease (CKD)
Chronic Kidney Disease (CKD) may not cause noticeable symptoms in its early stages, and even in advanced disease, urine output may remain normal. When symptoms do occur, they are often nonspecific and can be easily attributed to other conditions.
If you experience any of these symptoms, talk to your doctor.
Common symptoms of CKD include:
- Fatigue, weakness, low energy, and pale skin (often related to anemia)
- Loss of appetite, nausea, and vomiting
- Frequent urination, especially at night
- Fluid retention, causing swelling in the legs, ankles, or around the eyes
- Persistent itching
- Headaches
- Numbness or tingling in the hands and feet (peripheral neuropathy)
- Disturbed sleep and restless legs
- Difficulty concentrating or changes in mental clarity
- Chest pain (due to inflammation around the heart)
- Shortness of breath (from fluid buildup in the lungs)
- Easy bruising or bleeding
- Bone pain and increased risk of fractures
- Decreased sexual interest or erectile dysfunction
- Lightheadedness or reduced strength
Risk Factors and Causes of Chronic Kidney Disease (CKD)
Chronic Kidney Disease (CKD) can result from primary disorders of the kidneys, but more commonly develops as a complication of other underlying conditions. If you experience any of these symptoms, talk to your doctor. The most significant risk factors include:
Diabetes
Diabetes is the leading cause of CKD. Over time, elevated blood glucose levels can damage the blood vessels in the kidneys, impairing their ability to filter waste effectively. Both Type 1 and Type 2 diabetes significantly increase the risk of kidney disease, and regular monitoring is essential.
Hypertension (High Blood Pressure)
Uncontrolled high blood pressure can damage the small blood vessels in the kidneys, reducing their ability to function properly and contributing to progressive kidney damage.
Atherosclerosis
Narrowing and hardening of the arteries can reduce blood flow to the kidneys (ischemic nephropathy), leading to gradual loss of kidney function.
Glomerulonephritis
This group of diseases involves inflammation of the kidney’s filtering units (glomeruli), which can lead to impaired filtration and, in some cases, kidney failure. Causes include autoimmune conditions such as lupus and certain infections.
Obstruction of Urinary Flow
Conditions such as an enlarged prostate or urinary tract strictures can block the normal flow of urine, increasing pressure in the kidneys and potentially causing damage over time.
Polycystic Kidney Disease (PKD)
A hereditary condition characterized by the development of fluid-filled cysts in the kidneys, which can impair kidney function.
Medication-Related Kidney Injury
Long-term or excessive use of certain medications—particularly nonsteroidal anti-inflammatory drugs (NSAIDs) and some analgesics—can contribute to kidney damage.
Other Contributing Conditions
Additional causes of CKD include HIV infection, sickle cell disease, chronic kidney infections, amyloidosis, substance abuse, and certain cancers.
References
- Coresh J, Selvin E, Stevens LA, et al. Prevalence of Chronic Kidney Disease in the United States. JAMA. 2007;298(17):2038–2047.
- National Kidney Foundation. About Chronic Kidney Disease.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Chronic Kidney Disease (CKD)
World Health Organization. Global Health Estimates: Leading Causes of Death and Disability.
Jha V, et al. Lancet. 2013;382(9888):260–272.