Your kidneys are two fist-sized organs that sit on either side of your spine, just below your rib cage. They work continuously — filtering roughly 200 liters of blood every day, removing waste products, balancing fluid levels, regulating blood pressure, producing hormones that signal the body to make red blood cells, and keeping minerals like sodium, potassium, and phosphorus in careful balance. When the kidneys begin to lose this filtering capacity — gradually, over months and years — the condition is called chronic kidney disease, or CKD. CKD affects approximately 10 percent of the global population, making it one of the most common chronic conditions in the world. Yet most people with CKD, particularly in the early stages, have no symptoms. This silence is one of the defining and most dangerous features of the disease. ## How Kidney Function Is Measured The standard measure of kidney function is the eGFR — estimated glomerular filtration rate. It is calculated from a blood creatinine level (a waste product the kidneys filter) along with age, sex, and sometimes race, and it estimates how many milliliters of blood your kidneys are filtering per minute. A healthy eGFR is generally 90 or above. CKD is defined as an eGFR below 60 that persists for more than three months, or the presence of markers of kidney damage (such as protein in the urine) regardless of eGFR. Kidney disease is categorized into five stages based on eGFR: - **Stage 1:** eGFR 90 or above, with signs of kidney damage (such as protein in the urine). Kidney function is still normal or high.- **Stage 2:** eGFR 60–89, with signs of kidney damage. Mildly reduced function.- **Stage 3a / 3b:** eGFR 45–59 and 30–44. Moderately reduced function. This is when complications begin to emerge.- **Stage 4:** eGFR 15–29. Severely reduced function. Preparation for kidney replacement therapy typically begins at this stage.- **Stage 5:** eGFR below 15. Kidney failure. Dialysis or a kidney transplant is required to sustain life. The majority of people with CKD are in stages 1 through 3 — and most of them do not know it. ## Why CKD Is Usually Symptom-Free Until Late Stages The kidneys have enormous reserve capacity. They can lose up to 60 to 70 percent of their function before significant symptoms appear. By that point, a person is already in Stage 4 or approaching Stage 5. When symptoms do appear in advanced CKD, they include fatigue, shortness of breath, swelling in the legs and ankles, decreased urine output, difficulty concentrating, loss of appetite, nausea, and itching. Itching — caused by the buildup of waste products the kidneys can no longer remove — is particularly associated with late-stage disease. But here is the crucial point: waiting for symptoms is waiting too long. The damage accumulates silently. And unlike some organs, the kidneys have limited capacity to regenerate. Function lost to CKD is generally not recovered — which is why early detection and protection of remaining function are everything. > "The kidneys' silence is not reassurance. It is the disease's most dangerous feature. By the time CKD announces itself through symptoms, the window for meaningful intervention has often narrowed significantly." ## The Two Biggest Causes — And Why They Matter Together Diabetes and high blood pressure together account for approximately two-thirds of all cases of kidney failure in the United States and a similar proportion globally. **Diabetic kidney disease.** Sustained high blood glucose damages the delicate blood vessels and filtering units (glomeruli) of the kidneys over time. Protein begins to leak into the urine — an early warning sign called microalbuminuria — before eGFR begins to decline. This is why annual urine protein testing is a standard part of diabetes care: it catches kidney damage before it becomes kidney disease. **Hypertensive kidney disease.** High blood pressure places chronic mechanical stress on kidney blood vessels, progressively reducing their capacity to filter effectively. Conversely, damaged kidneys often worsen blood pressure — creating a self-reinforcing cycle. This is why blood pressure control is one of the most powerful tools for slowing CKD progression regardless of the original cause. Other causes of CKD include glomerulonephritis (immune-mediated inflammation of the kidney's filtering units), polycystic kidney disease (a genetic condition causing cysts to grow in the kidneys), recurrent kidney infections, chronic use of certain medications including NSAIDs (like ibuprofen), and rare autoimmune conditions. ## Who Is Most at Risk Beyond diabetes and hypertension, several factors significantly increase CKD risk. Family history of kidney disease is an important signal — particularly for conditions like polycystic kidney disease, which is inherited. Obesity, smoking, and a history of acute kidney injury all increase risk. Certain ethnic groups carry disproportionate CKD burden. Black Americans develop kidney failure at three to four times the rate of white Americans — a disparity driven by a higher prevalence of hypertension and a genetic variant (APOL1) associated with increased kidney disease risk. Filipino Americans have among the highest rates of kidney failure of any Asian American group, in large part due to elevated rates of diabetes and hypertension. South Asian and Pacific Islander communities also carry elevated risk. These disparities are not inevitable. They reflect biology intersecting with structural inequities in access to care, screening, and management. Closing these gaps begins with screening — and with clear information reaching communities in languages they can fully understand. ## What Slows the Progression of CKD CKD is not curable in most cases, but it is often very manageable. Protecting the kidney function that remains is the central goal, and the tools for doing so are well-established. **Control blood pressure rigorously.** The target for most people with CKD is below 130/80 mmHg. ACE inhibitors and ARBs — two classes of blood pressure medication — have the additional benefit of protecting the kidneys' filtering units from pressure damage and are generally the preferred agents in people with CKD, particularly in the presence of diabetes or proteinuria. **Control blood glucose in diabetic patients.** Tight glycemic control slows the progression of diabetic kidney disease. Newer diabetes medications — particularly SGLT-2 inhibitors such as dapagliflozin and empagliflozin — have demonstrated kidney-protective effects that go beyond glucose control and are now recommended as part of standard CKD management in eligible patients. **Reduce protein in the urine.** Proteinuria — protein leaking into the urine — is both a marker and a driver of kidney damage. Treatments that reduce proteinuria, particularly ACE inhibitors and ARBs, have been shown to slow CKD progression independent of their blood pressure effects. **Avoid nephrotoxic medications.** NSAIDs — including ibuprofen (Advil, Motrin) and naproxen (Aleve) — are among the most commonly used over-the-counter medications in the world, but they reduce blood flow to the kidneys and can accelerate CKD progression with regular use. People with CKD should generally avoid them, or use them only briefly and at the lowest effective dose, ideally under medical guidance. Certain contrast dyes used in imaging studies and some antibiotics also require dose adjustments in CKD. **Dietary adjustments.** In later stages of CKD, managing potassium, phosphorus, and sodium becomes important. Phosphorus accumulates in the blood when kidney function is reduced, contributing to bone disease and cardiovascular risk. Potassium, normally regulated by the kidneys, can reach dangerous levels when they are failing. Dietary counseling from a renal dietitian is an important part of CKD care from Stage 3 onward. **Protect against acute kidney injury (AKI).** People with CKD are more vulnerable to sudden drops in kidney function — from dehydration, serious infection, or certain medications. Each episode of AKI can accelerate the progression of underlying CKD. Staying well-hydrated, managing infections promptly, and reviewing medications with your provider during illness are practical ways to reduce this risk. ## Dialysis and Transplant — Understanding Kidney Replacement Therapy When kidney function falls below approximately 10 to 15 percent — Stage 5 — the kidneys can no longer sustain life without replacement. Dialysis and kidney transplantation are the two forms of kidney replacement therapy. **Hemodialysis** filters blood through a machine, typically three times a week for three to five hours per session, at a dialysis center or at home. It is effective but demanding — requiring significant time commitment and dietary restrictions between sessions. **Peritoneal dialysis** uses the lining of the abdomen as a natural filter. Fluid is introduced through a catheter, waste products diffuse across the membrane, and the fluid is drained. It can often be done overnight at home, offering more flexibility for many patients. **Kidney transplantation**, when possible, offers a better quality of life and longer survival than dialysis for most patients. Living-donor transplants (from a compatible family member or friend) generally have better outcomes than deceased-donor transplants. The waiting list for deceased-donor kidneys in many countries is long — making early referral to transplant evaluation important for eligible patients. ## A Note on Advance Planning and Informed Decisions For patients approaching Stage 4 and 5 CKD, one of the most important conversations — and one that is too often deferred — is what kind of kidney replacement therapy best fits their life, their values, and their overall health situation. For elderly patients with multiple serious conditions, conservative management (focused on comfort, quality of life, and symptom control without dialysis) is a legitimate and sometimes medically appropriate choice. This conversation deserves to happen early, with clarity, and ideally involving family. For immigrant patients and their families navigating this conversation across a language barrier — with complex medical terminology, difficult trade-offs, and high emotional stakes — the importance of genuine comprehension cannot be overstated. Nodding along is not understanding. Understanding is the foundation of a truly informed decision. --- *This article is for educational purposes only and does not constitute medical advice. Chronic kidney disease requires individualized medical assessment and management. Always consult your physician or a qualified nephrologist before making changes to your care.* Neuroscience Diagnostics Patient care Research
