Diabetes is the leading cause of kidney failure in the United States, followed by high blood pressure. Together, these two conditions account for the vast majority of cases. Behind them, a group of inflammatory kidney diseases called glomerulonephritis ranks third, and polycystic kidney disease, a genetic condition, ranks fourth, responsible for about 5% of all kidney failure cases.
How Diabetes Damages the Kidneys
Your kidneys filter blood through tiny clusters of blood vessels called glomeruli. When blood sugar stays elevated over months and years, excess glucose essentially coats the proteins in those filters through a process called glycosylation. This triggers a chain reaction: the cells within the filter begin to multiply abnormally, the surrounding tissue thickens and expands, and the delicate filtering membrane itself becomes damaged and stiff. Over time, the filters lose their ability to separate waste from the substances your body needs, which is why protein starts leaking into the urine, one of the earliest detectable signs of kidney trouble.
This damage doesn’t happen overnight. Most people with diabetes-related kidney disease progress through stages over 10 to 20 years before reaching kidney failure. The kidneys have significant reserve capacity, so by the time symptoms like swelling, fatigue, or changes in urination become noticeable, a substantial amount of function has already been lost.
High Blood Pressure Creates a Destructive Cycle
High blood pressure is the second most common cause of kidney failure, and it works through a different mechanism than diabetes. Sustained high pressure constricts and damages the small blood vessels throughout the kidneys, reducing the blood flow they need to function. When these vessels weaken, the kidneys can no longer remove wastes and excess fluid efficiently. That extra fluid stays in the bloodstream, which raises blood pressure further, creating a self-reinforcing cycle that accelerates damage with each pass.
This is why blood pressure control is so central to protecting kidney function. Current guidelines from the international kidney disease organization KDIGO recommend that adults with chronic kidney disease aim for a systolic blood pressure (the top number) below 120 mm Hg when tolerated. Hitting that target can meaningfully slow or stall progression toward kidney failure.
Glomerulonephritis and Polycystic Kidney Disease
Glomerulonephritis is a broad term for conditions where the kidney’s filters become inflamed. This can happen because of an autoimmune disorder, an infection, or sometimes without an identifiable trigger. The inflammation damages the glomeruli directly, impairing their ability to filter blood. Some forms progress slowly over years, while others can cause rapid decline.
Polycystic kidney disease (PKD) is inherited. The most common form, autosomal dominant PKD, is caused by mutations in one of two specific genes that together account for over 90% of affected families. Fluid-filled cysts grow progressively in both kidneys, crowding out healthy tissue. Symptoms often first appear between ages 30 and 40, and the disease advances over decades. According to CDC data, PKD accounts for about 5% of all kidney failure in the United States.
When Acute Injury Becomes Permanent
Not all kidney failure develops gradually. Acute kidney injury, a sudden drop in kidney function, can occur from severe dehydration, medication toxicity, major infections, or a sharp drop in blood flow to the kidneys during surgery or illness. In many cases, acute injury is reversible with prompt treatment. But each episode leaves behind some degree of scarring, and people who already have chronic kidney disease are especially vulnerable. Their kidneys have less reserve to absorb the hit, and repeated acute injuries can tip the balance toward permanent failure.
Who Is Most at Risk
Age is one of the strongest risk factors. About 34% of adults 65 and older have some degree of chronic kidney disease, compared with 13% of those aged 45 to 64 and just 6% of adults 18 to 44. This reflects the cumulative toll of conditions like diabetes and high blood pressure over a lifetime, combined with the natural decline in kidney function that comes with aging.
Race and ethnicity also play a significant role, driven by a combination of genetic susceptibility, rates of underlying conditions, and disparities in healthcare access. About 22% of non-Hispanic Black adults have chronic kidney disease, compared with 13% of non-Hispanic White adults and 12% of Hispanic adults. The gap widens dramatically at the most severe stage: Black Americans are more than four times as likely as White Americans to develop kidney failure. Hispanic and Native American populations face more than double the risk, and Asian Americans about 1.6 times the risk. Black Americans make up roughly 14% of the U.S. population but account for 30% of all people living with kidney failure.
Family history of kidney failure and existing heart disease also raise your risk, regardless of demographic group.
How Kidney Failure Is Defined
Doctors measure kidney function using a number called the estimated glomerular filtration rate, or eGFR, which tells you what percentage of normal filtering capacity your kidneys still have. Chronic kidney disease is divided into five stages based on this number. Stage 5, kidney failure, is defined as an eGFR below 15, meaning the kidneys are operating at less than 15% of normal capacity. At this point, the kidneys can no longer sustain life on their own, and treatment with dialysis or a kidney transplant becomes necessary.
The progression from early-stage kidney disease to stage 5 is not inevitable. Controlling blood sugar if you have diabetes, keeping blood pressure in a healthy range, and catching kidney problems early through routine blood and urine tests can slow or even halt the decline for many people. The challenge is that chronic kidney disease rarely causes symptoms in its earlier stages, which is why screening matters, particularly if you carry any of the risk factors above.