Chronic kidney disease is a long-term loss of kidney function that affects more than 1 in 7 American adults, yet most people who have it do not know, because the early stages usually cause no symptoms at all. The kidneys quietly filter waste and extra fluid from the blood, balance minerals, and help control blood pressure, so when they weaken over months and years, problems can build up unnoticed until the disease is advanced. The good news is that chronic kidney disease is often detectable with simple blood and urine tests long before symptoms appear, and newer treatments can meaningfully slow its progression. This guide explains what chronic kidney disease is, its symptoms, causes, how it is diagnosed and staged, the treatments available today, and the latest research.
What is chronic kidney disease?
Chronic kidney disease means the kidneys have been damaged or are filtering less effectively for at least three months. Healthy kidneys remove waste products and excess water, keep minerals like sodium, potassium, and calcium in balance, and release hormones that regulate blood pressure and red blood cell production. As kidney function declines, waste and fluid accumulate and these other jobs falter, which is why advanced kidney disease affects the whole body.
The condition is common and often silent. An estimated 35.5 million American adults have chronic kidney disease, and about 87 percent of them are unaware of it because early disease rarely causes noticeable symptoms. Its frequency rises sharply with age, and it is the reason routine testing matters so much, since catching it early opens the door to treatments that can protect kidney function for years.
Symptoms of chronic kidney disease
In its early stages, chronic kidney disease usually causes no symptoms, which is why it is often found only through blood and urine tests done for other reasons. As kidney function drops further, symptoms gradually emerge as waste and fluid build up in the body.
Later symptoms can include fatigue and trouble concentrating, swelling in the legs, ankles, or feet, foamy urine or changes in how often you urinate, poor appetite and nausea, muscle cramps, and dry, itchy skin. Because these signs are easy to attribute to other causes, they often appear only once the disease is well established, reinforcing the value of routine screening in people at higher risk. Swelling and shortness of breath can also reflect the fluid overload that links kidney disease with the weakened pumping of heart failure, since the heart and kidneys are closely connected.
What causes chronic kidney disease?
The two leading causes of chronic kidney disease are diabetes and high blood pressure, which together account for most cases. Over time, high blood sugar damages the tiny filtering units of the kidneys, and sustained high blood pressure strains the blood vessels that supply them. Managing these two conditions well is one of the most powerful ways to protect the kidneys, which is why guides to the blood sugar problems of diabetes and the elevated readings of high blood pressure are so relevant to kidney health.
Other contributors include cardiovascular disease, obesity, older age, a family history of kidney failure, smoking, and repeated or long-term use of certain medications. Some people are also at higher risk due to inherited conditions or recurrent kidney problems. Because the risk factors are so common, national guidelines encourage regular testing for anyone with diabetes, high blood pressure, or a family history of kidney disease.
How chronic kidney disease is diagnosed and staged
Chronic kidney disease is diagnosed and tracked with two simple tests that together capture how well the kidneys filter and whether they are leaking protein. The first is the estimated glomerular filtration rate, or eGFR, a calculation based on a blood creatinine level along with age and sex; a sustained eGFR below 60 signals reduced function. The second is the urine albumin-to-creatinine ratio, which detects small amounts of the protein albumin leaking into the urine, an early sign of kidney damage that can appear even when eGFR is still normal.
These come from familiar lab values, and understanding them helps you follow your own kidney health. It is worth knowing what a creatinine blood test measures, how the eGFR estimates your filtering rate, and what the albumin-to-creatinine ratio reveals about protein in the urine. Doctors may add a cystatin C test, which is not affected by muscle mass, to confirm the eGFR near diagnostic cutoffs, and a blood urea nitrogen test as a supporting marker of waste clearance. Kidney disease is then staged using the framework below, combined with the albumin result.
| Stage | eGFR (mL/min/1.73m²) | What it means |
|---|---|---|
| G1 | 90 or higher | Normal filtering, but with signs of kidney damage such as protein in the urine |
| G2 | 60 to 89 | Mildly reduced filtering with evidence of damage |
| G3a and G3b | 30 to 59 | Moderately reduced filtering; complications become more likely |
| G4 | 15 to 29 | Severely reduced filtering; preparation for future treatment begins |
| G5 | Below 15 | Kidney failure, which may require dialysis or a transplant |
Treatment options for chronic kidney disease
Treatment aims to slow the loss of kidney function, treat the underlying cause, and prevent complications. Controlling blood pressure and blood sugar is foundational, and in recent years several medication classes have been shown to protect the kidneys directly.
| Approach | Examples | Role |
|---|---|---|
| Blood pressure control | ACE inhibitors, ARBs | Lower pressure and reduce protein leakage to protect the kidneys |
| SGLT2 inhibitors | Dapagliflozin, empagliflozin | Slow kidney decline in many people, with or without diabetes |
| Other kidney-protective drugs | Finerenone, certain GLP-1 receptor agonists | Add further protection, especially in diabetic kidney disease |
| Lifestyle and diet | Lower sodium, healthy diet, exercise, no smoking | Support blood pressure, weight, and overall kidney health |
| Advanced disease care | Dialysis, kidney transplant | Replace kidney function when failure is reached |
Alongside these medicines, people with chronic kidney disease are usually advised to limit sodium, avoid nonsteroidal anti-inflammatory painkillers that can stress the kidneys, and work with their care team on a kidney-friendly eating plan. As the disease advances, treatment also addresses complications such as anemia, high potassium, and bone-mineral problems. When the kidneys reach failure, dialysis or a kidney transplant takes over the work of filtering the blood.
Living with chronic kidney disease and long-term outlook
Most people with chronic kidney disease never reach kidney failure, especially when the condition is caught early and managed well. Regular monitoring of eGFR and urine albumin allows treatment to be adjusted as needed, and controlling blood pressure, blood sugar, and weight can slow or even stabilize the disease. Because heart disease is the most common cause of death in people with chronic kidney disease, protecting the heart is just as important as protecting the kidneys.
Living well also means managing complications proactively. Declining kidney function can lower red blood cell production and lead to anemia, so blood counts are watched over time, and understanding the low red blood cell counts of anemia helps explain related fatigue. Bone health, potassium levels, and nutrition are all monitored as part of comprehensive kidney care, and a coordinated team helps people stay ahead of problems.
Latest scientific advances in chronic kidney disease research
The last few years have brought some of the most significant advances in kidney medicine in decades, expanding the toolkit well beyond blood pressure control. According to PubMed-indexed research, the 2024 FLOW trial in the New England Journal of Medicine found that the GLP-1 receptor agonist semaglutide reduced major kidney disease events by 24 percent in people with type 2 diabetes and chronic kidney disease, and also lowered cardiovascular events and deaths, with the trial stopped early for benefit (Perkovic et al., 2024). What this means for you: a medication already widely used for diabetes and weight can now also protect the kidneys, giving many people an additional layer of defense.
The EMPA-KIDNEY trial, published in the New England Journal of Medicine in 2023, showed that the SGLT2 inhibitor empagliflozin cut the risk of kidney disease progression or cardiovascular death by 28 percent across a broad range of patients, including many without diabetes (Herrington et al., 2023). What this means for you: this class of drugs has become foundational for chronic kidney disease, not just a diabetes treatment. Tying it all together, the 2024 KDIGO guideline, summarized in Kidney International, was the first full update since 2012 and folded SGLT2 inhibitors, finerenone, and GLP-1 receptor agonists into a unified, risk-based treatment plan (Levin et al., 2024). What this means for you: your care team now has a clear roadmap for layering several kidney-protective therapies based on your specific stage and risk, moving well beyond the older one-size approach.
Glossary of key chronic kidney disease terms
| Term | Definition |
|---|---|
| eGFR | The estimated glomerular filtration rate, a measure of how well the kidneys filter blood. |
| Creatinine | A waste product filtered by the kidneys, used to calculate eGFR. |
| Albumin-to-creatinine ratio | A urine test that detects protein leaking from damaged kidneys. |
| Cystatin C | An alternative blood marker of filtration not affected by muscle mass. |
| Proteinuria | Protein in the urine, an early sign of kidney damage. |
| Dialysis | A treatment that filters the blood when the kidneys can no longer do so. |
| SGLT2 inhibitor | A drug class that slows kidney decline in many people with chronic kidney disease. |
Frequently asked questions about chronic kidney disease
What are the five stages of chronic kidney disease?
The stages run from G1 to G5 based on eGFR. G1 and G2 involve normal or mildly reduced filtering with signs of damage, G3 is moderate reduction, G4 is severe reduction, and G5 is kidney failure that may require dialysis or a transplant. The stage is combined with a urine albumin measurement to gauge risk.
What is a normal eGFR result?
A normal eGFR is generally 90 or above. An eGFR below 60 that persists for at least three months indicates chronic kidney disease, and lower numbers reflect more advanced disease. Because eGFR can vary, doctors look at trends over time rather than a single reading.
Can chronic kidney disease be reversed or cured?
Chronic kidney disease usually cannot be reversed, but its progression can often be slowed significantly, and in early stages it may be stabilized. Controlling blood pressure and blood sugar, using kidney-protective medications, and adopting healthy habits can protect remaining function for many years.
What are the early warning signs of kidney disease?
Early chronic kidney disease usually has no symptoms, which is why testing matters. When signs do appear, they can include fatigue, swelling in the legs or feet, foamy urine, changes in urination, poor appetite, and itchy skin. These often show up only once the disease has advanced.
What causes chronic kidney disease?
The leading causes are diabetes and high blood pressure, which damage the kidneys over time. Other contributors include heart disease, obesity, older age, smoking, a family history of kidney failure, and certain medications. Managing these risks is central to prevention.
How is chronic kidney disease diagnosed?
It is diagnosed with a blood test for eGFR, based on creatinine, and a urine test for the albumin-to-creatinine ratio, repeated over at least three months to confirm the findings. A cystatin C test and blood urea nitrogen can add detail, and the results are used to stage the disease.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases — Chronic Kidney Disease — NIDDK, 2024 — niddk.nih.gov
- Centers for Disease Control and Prevention — Chronic Kidney Disease Basics — CDC, 2024 — cdc.gov
- National Kidney Foundation — Chronic Kidney Disease — NKF, 2024 — kidney.org
- Perkovic V, Tuttle KR, Rossing P, et al. — Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes — New England Journal of Medicine, 2024 — doi.org/10.1056/NEJMoa2403347
- Herrington WG, Staplin N, Wanner C, et al. — Empagliflozin in Patients with Chronic Kidney Disease — New England Journal of Medicine, 2023 — doi.org/10.1056/NEJMoa2204233
- Levin A, Ahmed SB, Carrero JJ, et al. — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease — Kidney International, 2024 — doi.org/10.1016/j.kint.2023.10.016
Further reading
- See what the main kidney filtering marker means in this guide to the eGFR blood test.
- Understand the waste product used to estimate it in this guide to the creatinine blood test.
- Learn how early kidney damage is detected in this guide to the albumin-to-creatinine ratio.
- Explore a leading cause of kidney disease in this guide to the blood sugar problems of diabetes.
- Build confidence reading test results with this guide to reference ranges, flags, and next steps on a lab report.
Understand your lab results with BloodSense
Chronic kidney disease is one of the clearest cases where a lab report can catch trouble years before symptoms, since a quiet drop in eGFR or a trace of albumin in the urine is often the first and only sign. Whenever you receive results, seeing where each value sits against its reference range, and how the numbers change over time, makes them far easier to act on. BloodSense translates a full lab report into plain language, showing what each marker means and helping you track your kidney and overall health across visits instead of decoding one line at a time.
