DIABETIC NEPHROPATHY OVERVIEW
People with diabetes have a lot to juggle when it comes to their healthcare. Having diabetes puts you at risk of other health problems, including heart attacks, strokes, vision loss, nerve damage, and kidney disease. While all of that may sound overwhelming, there is some good news; many of the steps you need to take to prevent one of those complications may actually help to prevent them all.
This article will discuss the early signs of diabetic kidney disease, or what healthcare providers call diabetic nephropathy. People who develop diabetic nephropathy usually have no symptoms early on, although the condition puts them at risk of developing more serious kidney disease. More detailed information is available by subscription. (See "Overview of diabetic nephropathy".)
The kidneys play an important role in the body: they filter the blood, removing waste products and excess salt and water. If the kidneys become diseased, they falter in their task, leaving the blood polluted.
Finding out that you have early diabetic nephropathy can alert you that your kidneys are in danger. It is important to take steps to protect your kidneys before the problem advances. Information about advanced kidney disease is also available (see "Patient information: Chronic kidney disease (Beyond the Basics)").
In some cases, diabetic nephropathy can eventually cause the kidneys to stop working altogether. If that happens to you, you will need to have a kidney transplant or dialysis, a procedure that filters the blood artificially several times a week. (See "Patient information: Dialysis or kidney transplantation — which is right for me? (Beyond the Basics)".)
DIABETIC NEPHROPATHY SYMPTOMS
Diabetic nephropathy usually causes no symptoms, and people who have the condition often produce normal amounts of urine. To detect diabetic nephropathy, healthcare providers rely on tests that measure protein levels in the urine and blood tests to evaluate the level of kidney function.
When the kidneys are working normally, they prevent protein from leaking into the urine, so finding protein in the urine is a sign that the kidneys are in trouble. Often people who have diabetic nephropathy also have high blood pressure.
DIABETIC NEPHROPATHY RISK FACTORS
There are several factors that can increase your risk of developing diabetic nephropathy. These include:
●Having chronically elevated blood sugar levels
●Being overweight or obese
●Having a diabetes-related vision problem (diabetic retinopathy) or nerve damage (diabetic neuropathy) (see "Patient information: Diabetic neuropathy (Beyond the Basics)")
Having a family history of kidney disease or belonging to certain ethnic groups (eg, African American, Mexican, Pima Indian) can also increase your risk of diabetic nephropathy. But the factors listed above are the ones you can do something about.
DIABETIC NEPHROPATHY DIAGNOSIS
Urine tests are recommended once per year in people with type 1 diabetes, beginning about five years after diagnosis, and in people with type 2 diabetes, starting at the time of diagnosis.
The urine test is looking for a protein called albumin. If there is albumin (protein) in your urine, it means you have diabetic nephropathy. You may be told that you have "microalbuminuria." That simply means that you have trace amounts of protein in your urine, but it still means that you have nephropathy, assuming you do not have kidney disease caused by another condition. (See "Patient information: Protein in the urine (proteinuria) (Beyond the Basics)" and "Moderately increased albuminuria (microalbuminuria) in type 1 diabetes mellitus" and "Moderately increased albuminuria (microalbuminuria) in type 2 diabetes mellitus".)
The same urine test that is used to diagnose diabetic nephropathy will also be used to monitor your condition over time (see 'Monitor for signs of change' below).
DIABETIC NEPHROPATHY COMPLICATIONS
The key complication of diabetic nephropathy is more advanced kidney disease, called chronic kidney disease. (See "Patient information: Chronic kidney disease (Beyond the Basics)".)
Chronic kidney disease can, in turn, progress even further, eventually leading to total kidney failure and the need for dialysis or kidney transplantation. (See "Patient information: Dialysis or kidney transplantation — which is right for me? (Beyond the Basics)".)
DIABETIC NEPHROPATHY TREATMENT
People with diabetes often focus on keeping their blood sugar levels in the right ranges. And while it is important to control blood sugar, it turns out that controlling blood pressure is at least as important. That's because high blood sugar and high blood pressure work in concert to damage the blood vessels and organ systems. (See "Treatment of diabetic nephropathy".)
For these reasons, the most important things you can do to stall kidney disease and protect against other diabetes complications are to:
●Make healthy lifestyle choices
●Keep your blood sugar as close to normal as possible (see 'Manage blood sugar levels' below)
●Keep your blood pressure below 130/80, if possible (see 'Manage high blood pressure' below)
Lifestyle changes — Changing your lifestyle can have a big impact on the health of your kidneys. The following measures are recommended for everyone, but are especially important if you have diabetic nephropathy:
●Limit the amount of salt you eat (see "Patient information: Low-sodium diet (Beyond the Basics)")
●If you smoke, quit smoking (see "Patient information: Quitting smoking (Beyond the Basics)")
●Lose weight if you are overweight (see "Patient information: Diet and health (Beyond the Basics)" and "Patient information: Exercise (Beyond the Basics)" and "Patient information: Weight loss treatments (Beyond the Basics)")
Manage blood sugar levels — Keeping blood sugars close to normal can help prevent the long-term complications of diabetes mellitus. For most people, a target for fasting blood glucose and for blood glucose levels before each meal is 80 to 120 mg/dL (4.4 to 6.6 mmol/L); however, these targets may need to be individualized. (See "Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)".)
A blood test called A1C is also used to monitor blood sugar levels; the result provides an average of blood sugar levels over the last one to three months. An A1C of 7 percent or less is usually recommended; this corresponds to an average blood glucose of 150 mg/dL (8.3 mmol/L) (table 1). Even small decreases in the A1C lower the risk of diabetes-related complications to some degree.
Manage high blood pressure — Many people with diabetes have hypertension (high blood pressure). Although high blood pressure causes few symptoms, it has two negative effects: it stresses the cardiovascular system and speeds the development of diabetic complications of the kidney and eye. A healthcare provider can diagnose high blood pressure by measuring blood pressure on a regular basis. (See "Patient information: High blood pressure in adults (Beyond the Basics)".)
The treatment of high blood pressure varies. If you have mild hypertension, your healthcare provider may recommend weight loss, exercise, decreasing the amount of salt in the diet, quitting smoking, and decreasing alcohol intake. These measures can sometimes reduce blood pressure to normal. (See "Patient information: High blood pressure, diet, and weight (Beyond the Basics)".)
If these measures are not effective or your blood pressure needs to be lowered quickly, your provider will likely recommend one of several high blood pressure medications. Your provider can discuss the pros and cons of each medication and the goals of treatment. (See "Patient information: High blood pressure treatment in adults (Beyond the Basics)".)
A blood pressure reading below 130/80 is the recommended goal for most people with diabetic nephropathy.
Blood pressure medications — Most people with diabetic nephropathy need at least one medication to lower their blood pressure. Several medications can be used for this purpose, but a medication known as an angiotensin-converting enzyme inhibitor (abbreviated ACE inhibitor) or a related drug known as an angiotensin receptor blocker (ARB) are used most commonly. ACE inhibitors are generally used first because they have been available longer than ARBs.
ACE inhibitors and ARBs are particularly useful for people with diabetic nephropathy because they decrease the amount of protein in the urine and can prevent or slow the progression of diabetes-related kidney disease. In fact, the kidney benefits of ACE inhibitors and ARBs are so robust that healthcare providers sometimes prescribe them for people with diabetic nephropathy who have normal blood pressure.
Still, despite their kidney-protecting abilities, ACE inhibitors and ARBs do have their downsides. For instance, ACE inhibitors cause a persistent dry cough in 5 to 20 percent of the people who take them. Some people get used to the cough; others find it so disruptive that they cannot continue taking an ACE inhibitor. For them, ARBs are often a good alternative, because ARBs are less likely to cause a cough.
In rare cases, you can have more serious side effects with ACE inhibitors and ARBs. These include a decrease in kidney function or a condition called hyperkalemia, in which too much potassium accumulates in the blood. To monitor for these and other side effects, healthcare providers sometimes run blood tests soon after starting these drugs. In some people, the medications will need to be stopped.
More information on the risks and side effects of ACE inhibitors and ARBs is available (see "Major side effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers").
Monitor for signs of change — After beginning treatment and lifestyle changes to stall kidney disease, you will need to have repeat urine and blood tests to determine if urine protein levels have improved. If the urine protein levels have not improved or your kidney function has worsened, your healthcare provider may need to adjust your medications or recommend other strategies to protect your kidneys.
PREGNANCY AND DIABETIC NEPHROPATHY
If you have diabetes and are interested in getting pregnant, it is important to talk with your healthcare provider well in advance, especially if you have diabetic nephropathy. Diabetes and its attendant problems can increase the risk of complications in pregnancy, especially in women with decreased kidney function. However, many women with mild diabetic nephropathy have normal pregnancies and healthy babies. (See "Pregnancy in women with underlying renal disease".)
To ensure the best outcome with a pregnancy, the most important thing you can do is to keep your blood sugar and blood pressure under tight control. However, women who are pregnant or attempting to get pregnant should not take ACE inhibitors or ARBs, as these drugs can cause birth defects. Instead, other medications (such as calcium channel blockers) are used during pregnancy to keep the blood pressure in check. (See "Patient information: Care during pregnancy for women with type 1 or 2 diabetes mellitus (Beyond the Basics)".)
DIABETIC KIDNEY DISEASE AND OTHER DIABETES COMPLICATIONS
If the steps you need to take to protect your kidneys sound overwhelming, keep this in mind; controlling your blood sugar and blood pressure can help to reduce the risk or severity of several other debilitating diabetes complications, including:
●Vision loss (due to diabetic retinopathy)
●Nerve damage (called diabetic neuropathy)
●Stroke and heart attack (both of which can be fatal)
DIABETIC NEPHROPATHY PREVENTION
The same measures that are used in the treatment of diabetic kidney disease are also useful in preventing it. That's true for the lifestyle choices mentioned above, as well as for the tight control of blood sugar levels and blood pressure.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Type 2 diabetes (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Chronic kidney disease (Beyond the Basics)
Patient information: Dialysis or kidney transplantation — which is right for me? (Beyond the Basics)
Patient information: Diabetic neuropathy (Beyond the Basics)
Patient information: Protein in the urine (proteinuria) (Beyond the Basics)
Patient information: Low-sodium diet (Beyond the Basics)
Patient information: Quitting smoking (Beyond the Basics)
Patient information: Diet and health (Beyond the Basics)
Patient information: Exercise (Beyond the Basics)
Patient information: Weight loss treatments (Beyond the Basics)
Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)
Patient information: High blood pressure in adults (Beyond the Basics)
Patient information: High blood pressure, diet, and weight (Beyond the Basics)
Patient information: High blood pressure treatment in adults (Beyond the Basics)
Patient information: Care during pregnancy for women with type 1 or 2 diabetes mellitus (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Aldose reductase inhibitors in the prevention of diabetic complications
Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults
Dialysis in diabetic nephropathy
Moderately increased albuminuria (microalbuminuria) in type 1 diabetes mellitus
Moderately increased albuminuria (microalbuminuria) in type 2 diabetes mellitus
Overview of diabetic nephropathy
Pregnancy in women with diabetic kidney disease
Renal transplantation in diabetic nephropathy
Treatment of diabetic nephropathy
Major side effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers
Pregnancy in women with underlying renal disease
The following organizations also provide reliable health information:
●National Library of Medicine
●National Institute of Diabetes and Digestive and Kidney Diseases
●American Diabetes Association (ADA)
●The Hormone Health Network
(http://www.hormone.org/diseases-and-conditions/diabetes, available in English and Spanish)