How does diabetes cause kidney disease? High blood sugar slowly damages the small blood vessels and filters inside the kidneys. This damage makes it harder for the kidneys to clean the blood and keep useful protein inside the body. High blood pressure, which is common in people with diabetes, can add more stress and speed up the damage.
Kidney damage from diabetes usually develops over many years. Most people do not notice symptoms during the early stages. Regular urine and blood tests are the best way to find the problem before serious damage occurs. About 1 in 3 adults with diabetes has chronic kidney disease.
Understanding the Link Between Diabetes and the Kidneys
The kidneys are two organs located near the middle of the back. Their main job is to filter waste and extra water from the blood. They also help control blood pressure, balance minerals, and make hormones that support healthy blood cells and bones.
Each kidney contains many tiny filtering units called nephrons. Inside each nephron are small blood vessels that act like filters. They allow waste and extra fluid to leave the blood while keeping blood cells and useful proteins in the body.
Diabetes causes blood sugar to remain too high. Over time, this excess sugar can harm the small blood vessels in the kidneys. The filters may become weak, scarred, or leaky. When that happens, the kidneys cannot clean the blood as well as they should.
Kidney disease caused by diabetes is often called diabetic kidney disease, diabetic nephropathy, or chronic kidney disease related to diabetes.
Both type 1 and type 2 diabetes can damage the kidneys. The risk usually rises when a person has lived with diabetes for many years, has frequent high blood sugar, or also has high blood pressure.
Why High Blood Sugar Damages Kidney Filters
When blood sugar remains high, the kidneys must work harder to filter the blood. At first, this extra work may make the kidneys filter more than normal. A person may not feel any different during this stage.
Over time, high glucose damages the walls of the small blood vessels in the nephrons. The filters may become thicker and less effective. They can also begin allowing albumin, an important blood protein, to pass into the urine.
Healthy kidneys normally keep most albumin in the blood. Finding too much albumin in urine may be an early sign that the filters have become damaged.
As the damage continues, scar tissue can form. Healthy filtering tissue may be replaced by tissue that cannot filter waste properly. Kidney function may then fall slowly over several years.
This process does not happen to every person with diabetes. Good glucose control, healthy blood pressure, regular testing, and the right medicine can help prevent or slow kidney damage.
How High Blood Pressure Makes the Damage Worse
High blood pressure is common among people with diabetes. It can damage the same small blood vessels that high blood sugar affects.
Blood pressure is the force of blood pushing against the walls of the blood vessels. When this force remains too high, it puts extra pressure on kidney filters. The damaged filters may then leak more protein and lose function faster.
Kidney disease can also raise blood pressure. When damaged kidneys cannot remove enough salt and fluid, extra fluid may build up in the body. This can increase blood pressure even more.
This creates a harmful cycle:
- High blood pressure damages the kidneys.
- Damaged kidneys hold more salt and fluid.
- Extra fluid raises blood pressure.
- Higher pressure causes more kidney damage.
Controlling blood pressure is one of the most important parts of protecting kidney health. A medical professional should choose a personal blood pressure target based on age, health conditions, medicines, and kidney test results.
Early Kidney Disease Often Has No Symptoms
Diabetic kidney disease usually develops slowly. Most people do not notice clear symptoms during the early stages. A person may feel well even while albumin is leaking into the urine or kidney filtering ability is beginning to fall.
This is why symptoms should not be used as the only warning system. Waiting until a person feels sick may allow the disease to become more advanced.
As kidney function becomes worse, symptoms may include:
- Swelling in the feet, ankles, legs, hands, or face
- Foamy or bubbly urine
- Needing to urinate more often
- Feeling very tired
- Loss of appetite
- Nausea or vomiting
- Itchy or dry skin
- Muscle cramps
- Trouble sleeping
- Shortness of breath
These symptoms can also come from other medical conditions. Blood and urine testing is needed to find the cause.
Sudden swelling, severe shortness of breath, chest pain, confusion, very little urine, or extreme weakness requires prompt medical care.
Kidney Tests Used for People With Diabetes
Health care professionals usually use a urine test and a blood test to check for diabetic kidney disease.
The urine test looks for albumin. It is often called a urine albumin to creatinine ratio test. A higher result may mean the kidney filters are allowing protein to escape into the urine.
A single abnormal test does not always confirm chronic kidney disease. Exercise, fever, infection, very high blood sugar, or other temporary problems may affect the result. A clinician may repeat the test to confirm a pattern.
The blood test measures creatinine, a waste product produced by normal muscle activity. The result is used to estimate how well the kidneys filter blood. This estimate is called eGFR.
A lower eGFR may mean that kidney function has declined. Doctors look at the result over time instead of relying only on one test.
People with type 2 diabetes should generally receive kidney testing every year. People with type 1 diabetes should generally begin yearly testing after they have had diabetes for more than 5 years.
A clinician may test more often when albumin is found in urine, eGFR is falling, blood pressure is high, or kidney disease has already been diagnosed.
Factors That Increase the Risk of Kidney Damage
Having diabetes does not mean that kidney disease will definitely develop. Some people have a higher risk than others.
Important risk factors include:
- Blood sugar that often stays above the target
- High blood pressure
- Living with diabetes for many years
- Smoking
- Heart disease
- Overweight or obesity
- Low physical activity
- Eating too much sodium
- A family history of kidney failure
- Missing diabetes or blood pressure medicine
Poor glucose control and a longer duration of diabetes increase the chance of diabetic kidney disease. High blood pressure adds further stress to the kidney filtering system.
Risk is also shaped by age, family history, access to health care, and other health conditions. A person cannot change every risk factor, but many important risks can be managed.
The goal is not perfection. Small improvements in glucose control, blood pressure, activity, medicine use, and food choices can protect the kidneys over time.
How Blood Sugar Control Protects the Kidneys
Keeping blood sugar close to a personal target reduces the amount of stress placed on the kidney filters. It may also slow damage that has already started.
The A1C test shows average blood sugar during the previous 2 to 3 months. For many adults with diabetes, an A1C below 7 percent is a common goal, but the correct target varies. Age, pregnancy, other health problems, medicine side effects, and the risk of low blood sugar all matter.
Daily habits that may support glucose control include:
- Taking medicine as prescribed
- Checking blood sugar when directed
- Eating regular balanced meals
- Choosing foods with fiber
- Limiting sugary drinks
- Being physically active
- Getting enough sleep
- Managing stress
- Attending regular medical visits
- Reporting frequent high or low readings
A high reading does not always mean that permanent kidney damage has occurred. Kidney risk is more closely linked with patterns that continue over time.
Do not change insulin or another diabetes medicine without medical guidance. Some medicine doses may need adjustment when kidney function changes because the kidneys help clear certain medicines from the body.
Kidney Care for People in Atlanta, Georgia
People living with diabetes should discuss kidney screening during routine medical visits. Bring a list of medicines, recent glucose readings, blood pressure readings, and any previous kidney test results.
Ask your health care professional:
- What is my eGFR?
- Is there albumin in my urine?
- How often should my kidneys be tested?
- What blood pressure goal is right for me?
- Do any of my medicines need adjustment?
- Should I meet with a kidney specialist?
A kidney specialist is called a nephrologist. A referral may be helpful when kidney function falls quickly, albumin levels remain high, the cause is unclear, blood pressure is difficult to control, or kidney disease becomes advanced.
A registered dietitian may also help create an eating plan that considers diabetes, kidney function, sodium, protein, potassium, and personal food preferences.
Medicines That May Slow Kidney Disease
Several medicine groups may help protect the kidneys, depending on the person and the stage of disease.
ACE inhibitors and ARBs are blood pressure medicines that can reduce pressure inside the kidney filters. They may slow kidney damage in people with diabetes, high blood pressure, and albumin in the urine.
People should not take an ACE inhibitor and an ARB together unless a specialist gives a clear reason. These medicines may affect potassium and kidney test results, so monitoring is important.
For many adults with type 2 diabetes and chronic kidney disease, doctors may prescribe an SGLT2 inhibitor. Current diabetes standards recommend this medicine group for many people at higher risk because it can slow kidney disease progression and reduce heart failure risk.
Finerenone may be considered for certain adults with chronic kidney disease related to type 2 diabetes. The FDA has approved it to reduce the risk of kidney function decline, kidney failure, and certain heart complications. Potassium and kidney function must be checked because the medicine is not right for everyone.
Medicine choices depend on eGFR, urine albumin, potassium, blood pressure, heart health, cost, side effects, and other prescriptions.
Food and Lifestyle Habits That Support Kidney Health
A healthy eating plan can support blood sugar, blood pressure, heart health, and kidney function.
Helpful habits may include:
- Limiting foods that are high in sodium
- Eating more vegetables and suitable fruits
- Choosing whole grains when appropriate
- Controlling portions of carbohydrate foods
- Choosing lean protein
- Drinking water unless fluid intake is restricted
- Reducing sugary drinks
- Avoiding tobacco
- Staying physically active
- Working toward a healthy weight when needed
A kidney diet is not the same for every person. Someone with early kidney disease may have different needs from someone with advanced disease.
Do not greatly reduce protein, potassium, phosphorus, or fluids without professional advice. Unneeded restrictions may lead to poor nutrition.
Some pain medicines can harm kidney function, especially when used often, taken at high doses, or used during dehydration. Ask a clinician or pharmacist before regularly using pain relievers or supplements.
The CDC advises people with diabetes and kidney disease to follow an individual meal plan that supports blood sugar control and limits further kidney damage.
Can Diabetic Kidney Disease Be Prevented or Slowed?
Kidney damage cannot always be prevented, but many people can reduce their risk or slow the disease.
The most useful steps include:
- Keep blood sugar near your target.
- Control blood pressure.
- Complete yearly kidney tests.
- Take medicine as directed.
- Stop smoking.
- Limit sodium.
- Stay active.
- Manage cholesterol.
- Treat urinary infections promptly.
- Attend follow up visits.
Early detection gives people more treatment options. Kidney disease found through routine testing may be managed before serious symptoms appear.
Kidney damage may continue to get worse, but progression is not always rapid. NIDDK notes that many people with diabetes and kidney disease do not reach kidney failure.
A person should seek medical advice when urine albumin rises, eGFR falls, swelling develops, blood pressure becomes difficult to manage, or glucose levels change without a clear reason.
12. Frequently Asked Questions
Can type 2 diabetes cause kidney failure?
Yes. Type 2 diabetes can damage the kidney filters over many years. If damage becomes severe, the kidneys may lose most of their ability to remove waste and fluid. Diabetes remains a leading cause of kidney failure in the United States.
What is the first sign of diabetic kidney disease?
The earliest sign is often albumin in the urine. Most people do not feel symptoms during the early stage, which is why routine blood and urine tests are important.
Can kidney damage from diabetes be reversed?
Some early changes may improve when blood sugar and blood pressure are brought under better control. Established scarring is usually not fully reversible, but treatment can often slow further loss of kidney function.
Does every person with diabetes get kidney disease?
No. About 1 in 3 adults with diabetes has chronic kidney disease, which means many people do not develop it. Risk is affected by glucose control, blood pressure, duration of diabetes, smoking, family history, and other health factors.
How often should people with diabetes check their kidneys?
People with type 2 diabetes should generally have kidney tests every year. People with type 1 diabetes should generally begin annual testing after 5 years. More frequent testing may be needed when kidney disease is present.
Conclusion
Diabetes damages the kidneys by harming the small blood vessels and filters that clean the blood. High blood sugar weakens these filters, while high blood pressure adds more stress. Protein may begin leaking into urine, kidney function may fall, and waste can build up when the condition becomes advanced.
The damage usually develops slowly and may not cause early symptoms. Yearly urine and blood tests are essential. Good glucose control, healthy blood pressure, suitable medicine, balanced food choices, physical activity, and regular medical care can help protect kidney function.
For more clear and trustworthy health information, read additional diabetes guides from Books_WD and speak with a qualified health care professional about your personal kidney test results.
