What is diabetic nephropathy?
Nephropathy means kidney disease or damage. Diabetic nephropathy is damage to your kidneys caused by diabetes. In severe cases it can lead to kidney failure. But not everyone with diabetes has kidney damage.
What causes diabetic nephropathy?
The kidneys have many tiny blood vessels that filter waste from your blood. High blood sugar from diabetes can destroy these blood vessels. Over time, the kidney isn't able to do its job as well. Later it may stop working completely. This is called kidney failure.
Certain things make you more likely to get diabetic nephropathy. If you also have high blood pressure or high cholesterol, or if you smoke, your risk is higher. Also, Native Americans, African Americans, and Hispanics (especially Mexican Americans) have a higher risk.
What are the symptoms?
There are no symptoms in the early stages. So it's important to have regular urine tests to find kidney damage early. Sometimes early kidney damage can be reversed.
As your kidneys are less able to do their job, you may notice swelling in your body, most often in your feet and legs.
How is diabetic nephropathy diagnosed?
The problem is diagnosed using simple tests that check for a protein called albumin in the urine. Urine doesn't usually contain protein. But in the early stages of kidney damage—before you have any symptoms—some protein may be found in your urine, because your kidneys aren't able to filter it out the way they should.
Finding kidney damage early can keep it from getting worse. So it's important for people with diabetes to have regular testing, usually every year.
How is it treated?
The main treatment is medicine to lower your blood pressure and prevent or slow the damage to your kidneys. These medicines include:
- Angiotensin-converting enzyme inhibitors, also called ACE inhibitors.
- Angiotensin II receptor blockers, also called ARBs.
As damage to the kidneys gets worse, your blood pressure rises. Your cholesterol and triglyceride levels rise too. You may need to take more than one medicine to treat these complications.
And there are other steps you can take. For example:
- Keep your blood sugar levels within your target range. This can help slow the damage to the small blood vessels in the kidneys.
- Work with your doctor to keep your blood pressure under control. Your doctor will give you a goal for your blood pressure. Your goal will be based on your health and your age.
- Keep your heart healthy by eating healthy foods and exercising regularly. Preventing heart disease is important, because people with diabetes are more likely to have heart and blood vessel diseases. And people with kidney disease are at an even higher risk for heart disease.
- Watch how much protein you eat. Eating too much is hard on your kidneys. If diabetes has affected your kidneys, limiting how much protein you eat may help you preserve kidney function. Talk to your doctor or dietitian about how much protein is best for you.
- Watch how much salt you eat. Eating less salt helps keep high blood pressure from getting worse.
- Don't smoke or use other tobacco products.
How can diabetic nephropathy be prevented?
The best way to prevent kidney damage is to keep your blood sugar in your target range and your blood pressure under control. You do this by eating healthy foods, staying at a healthy weight, exercising regularly, and taking your medicines as directed.
At the first sign of protein in your urine, you can take high blood pressure medicines to keep kidney damage from getting worse.
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There are no symptoms in the early stages of diabetic nephropathy. If you have kidney damage, you may have small amounts of protein leaking into your urine (albuminuria). Normally, protein is not found in urine except during periods of high fever, strenuous exercise, pregnancy, or infection.
Not everyone with diabetes will develop diabetic nephropathy. In people with type 1 diabetes, diabetic nephropathy is more likely to develop 5 to 10 years or more after the onset of diabetes. People with type 2 diabetes may find out that they already have a small amount of protein in the urine at the time diabetes is diagnosed, because they may have had diabetes for several years.
As diabetic nephropathy progresses, your kidneys cannot do their job as well. They cannot clear toxins or drugs from your body as well. And they cannot balance the chemicals in your blood very well. You may:
- Lose more protein in your urine.
- Have higher blood pressure.
- Have higher cholesterol and triglyceride levels.
You may have symptoms if your nephropathy gets worse. These symptoms include:
- Swelling (edema), first in the feet and legs and later throughout your body.
- Poor appetite.
- Weight loss.
- Feeling tired or worn out.
- Nausea or vomiting.
- Trouble sleeping.
If the kidneys are severely damaged, blood sugar levels may drop because the kidneys cannot remove excess insulin or filter oral medicines that increase insulin production.
Exams and Tests
Diabetic nephropathy is diagnosed using tests that check for a protein (albumin) in the urine, which points to kidney damage. Your urine will be checked for protein (urinalysis) when you are diagnosed with diabetes.
An albumin urine test can detect very small amounts of protein in the urine that cannot be detected by a routine urine test, allowing early detection of nephropathy. Early detection is important, to prevent further damage to the kidneys. The results of two tests, done within a 3- to 6-month period, are needed to diagnose nephropathy.
When to begin checking for protein in the urine depends on the type of diabetes you have. After testing begins, it should be done every year.
Type of diabetes
When to begin yearly testing
Type 1 diabetes
After you have had diabetes for 5 years
Type 2 diabetes
When you are diagnosed with diabetes
Diabetes present during childhood
After age 10 and after the child has had diabetes for 5 years
An albuminuria dipstick test is a simple test that can detect small amounts of protein in the urine. The strip changes color if protein is present, providing an estimate of the amount of protein. A spot urine test for albuminuria is a more precise lab test that can measure the exact amount of protein in a urine sample. Either of these tests may be used to test your urine for protein.
You will also have a creatinine test done every year. The creatinine test is a blood test that shows how well your kidneys are working.
If your doctor suspects that the protein in your urine may be caused by a disease other than diabetes, other blood and urine tests may be done. You may have a small sample of kidney tissue removed and examined (kidney biopsy).
It is important to check your blood pressure regularly, both at home and in your doctor's office, because blood pressure rises as kidney damage progresses. Keeping your blood pressure at or below your target can prevent or slow kidney damage.
Your doctor might suggest a cholesterol and triglyceride test based on your age or your risk for heart disease. Talk to your doctor about when a cholesterol test is right for you.
For more information, see When to Have a Cholesterol Test.
Diabetic nephropathy is treated with medicines that lower blood pressure and protect the kidneys. These medicines may slow down kidney damage and are started as soon as any amount of protein is found in the urine. The use of these medicines before nephropathy occurs may also help prevent nephropathy in people who have normal blood pressure.
If you have high blood pressure, two or more medicines may be needed to lower your blood pressure enough to protect the kidneys. Medicines are added one at a time as needed.
If you take other medicines, avoid ones that damage or stress the kidneys, especially nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs include ibuprofen and naproxen.
It is also important to keep your blood sugar within your target range. Maintaining blood sugar levels within your target range prevents damage to the small blood vessels in the kidneys.
Limiting the amount of salt in your diet can help keep your high blood pressure from getting worse. You may also want to restrict the amount of protein in your diet. If diabetes has affected your kidneys, limiting how much protein you eat may help you preserve kidney function. Talk to your doctor or dietitian about how much protein is best for you.
Medicines that are used to treat diabetic nephropathy are also used to control blood pressure. If you have a very small amount of protein in your urine, these medicines may reverse the kidney damage. Medicines used for initial treatment of diabetic nephropathy include:
- Angiotensin-converting enzyme (ACE) inhibitors, such as captopril, enalapril, lisinopril, and ramipril. ACE inhibitors can lower the amount of protein being lost in the urine. Also, they may reduce your risk of heart and blood vessel (cardiovascular) disease.
- Angiotensin II receptor blockers (ARBs), such as candesartan cilexetil, irbesartan, losartan potassium, and telmisartan.
If you also have high blood pressure, two or more medicines may be needed to lower your blood pressure enough to protect your kidneys. Medicines are added one at a time as needed.
If you take other medicines, avoid ones that damage or stress the kidneys, especially nonsteroidal anti-inflammatory drugs (NSAIDs).
It is also important to keep your blood sugar within your target range to prevent damage to the small blood vessels in the kidneys.
As diabetic nephropathy progresses, blood pressure usually rises, making it necessary to add more medicine to control blood pressure.
Your doctor may advise you to take the following medicines that lower blood pressure. You may need to take different combinations of these medicines to best control your blood pressure. By lowering your blood pressure, you may reduce your risk of kidney damage. Medicines include:
- Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs).
- Calcium channel blockers, which lower blood pressure by making it easier for blood to flow through the vessels. Examples include amlodipine, diltiazem, or verapamil.
- Diuretics. Medicines such as chlorthalidone, hydrochlorothiazide, or spironolactone help lower blood pressure by removing sodium and water from the body.
- Beta-blockers lower blood pressure by slowing down your heartbeat and reducing the amount of blood pumped with each heartbeat. Examples include atenolol, carvedilol, or metoprolol.
Continue to avoid other medicines that may damage or stress the kidneys, especially nonsteroidal anti-inflammatory drugs (NSAIDs). And it is still important to keep your blood sugar within your target range, eat healthy foods, get regular exercise, and not smoke.
Treatment if the condition gets worse
If damage to the blood vessels in the kidneys continues, kidney failure may eventually develop. When that occurs, it is likely that you will need dialysis treatment (renal replacement therapy)—an artificial method of filtering the blood—or a kidney transplant to survive. To learn more, see the topic Chronic Kidney Disease.
What to think about
Diabetic nephropathy can get worse during pregnancy and can affect the growth and development of the fetus. If your nephropathy is not severe, your kidney function may return to its prepregnancy level after the baby is born. If you have severe nephropathy, pregnancy may lead to permanent worsening of your kidney function.
If you have nephropathy and are pregnant or are planning to become pregnant, talk with your doctor about which medicines you can take. You may not be able to take some medicines (for example, angiotensin-converting enzyme [ACE] inhibitors or angiotensin II receptor blockers [ARBs]) during pregnancy, because they may harm your developing baby.
Prevention is the best way to avoid kidney damage from diabetic nephropathy.
- Keep your blood sugar levels within your target range. Manage your blood sugar by eating healthy foods, taking your medicine, and getting regular exercise. Your doctor may want you to check your blood sugar several times each day.
- Have yearly testing for protein in your urine.
- If you have type 1 diabetes, begin urine tests for protein after you have had diabetes for 5 years.
- Children with type 1 diabetes should begin yearly urine protein screening when they are 10 years of age and have had diabetes for 5 years.
- If you have type 2 diabetes, begin screening at the time diabetes is diagnosed.
- Keep your blood pressure under control with medicine, diet, and exercise. Learn to check your blood pressure at home.
- Stay at a healthy weight. This can help you prevent other diseases, such as high blood pressure and heart disease.
- Follow the nutrition guidelines for hypertension (including the Dietary Approaches to Stop Hypertension, or DASH, diet).
- Do not smoke or use other tobacco products.
If you already have diabetic nephropathy, you may be able to slow the progression of kidney damage by:
- Avoiding dehydration by promptly treating other conditions—such as diarrhea, vomiting, or fever—that can cause it. Be especially careful during hot weather or when you exercise.
- Reducing your risk of heart disease. Lifestyle changes such as eating a heart-healthy diet, quitting smoking, and getting regular exercise can help reduce your overall risk of developing heart disease and stroke.
- Treating other conditions that may block the normal flow of urine out of the kidneys, such as kidney stones, an enlarged prostate, or bladder problems.
- Not using medicines that may be harmful to your kidneys, especially nonsteroidal anti-inflammatory drugs (NSAIDs). Be sure that your doctor knows about all prescription, nonprescription, and herbal medicines you are taking.
- Avoiding X-ray tests that require IV contrast material, such as angiograms, intravenous pyelography (IVP), and some CT scans. IV contrast can cause further kidney damage. If you do need to have these types of tests, make sure your doctor knows that you have diabetic nephropathy.
- Avoiding situations where you risk losing large amounts of blood, such as unnecessary surgeries. Do not donate blood or plasma.
- Lowering your blood pressure, because high blood pressure can make kidney damage even worse.
- Checking with your doctor to find out if it is safe for you to drink alcohol. Limiting alcohol can lower your blood pressure and lower your risk of kidney damage.
- American Diabetes Association (2019). Standards of medical care in diabetes—2019. Diabetes Care, 42(Suppl 1): S1–S193. Accessed December 17, 2018.
Other Works Consulted
- Brownlee M, et al. (2011). Complications of diabetes mellitus. In S Melmed et al., eds., Williams Textbook of Endocrinology, 12th ed., pp. 1462–1551. Philadelphia: Saunders.
- De Ferranti SD, et al. (2014). Type 1 diabetes mellitus and cardiovascular disease: A scientific statement from the American Heart Association and American Diabetes Association. Diabetes Care, published online August 11, 2014. DOI: 10.2337/dc14-1720. Accessed September 4, 2014.
- Parving H, et al. (2008). Diabetic nephropathy. In BM Brenner, ed., Brenner and Rector's The Kidney, 8th ed., vol. 2, pp. 1265–1298. Philadelphia: Saunders Elsevier.
- Shlipak M (2010). Diabetic nephropathy: Preventing progression, search date November 2009. BMJ Clinical Evidence. Available online: http://www.clinicalevidence.com.
- Tuttle KR, et al. (2014). Diabetic kidney disease: A report from an ADA consensus conference. Diabetes Care, 37(10): 2864–2883. DOI: 10.2337/dc14-1296. Accessed January 6, 2015.
Current as of: August 11, 2019
Author: Healthwise Staff
Medical Review: E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
Tushar J. Vachharajani MD, FASN, FACP - Nephrology
Current as of: August 11, 2019