People with diabetes are at high risk for kidney disease, but there are steps they can take to protect their kidneys.
Meda E. Pavkov, MD, PhD, medical epidemiologist in the Chronic Kidney Disease Initiative within the Division for Diabetes Translation at the Centers for Disease Control and Prevention (CDC), is a co-author of the “Kidney Disease in Diabetes” chapter in the NIDDK publication Diabetes in America, 3rd Edition. Here, she discusses the link between diabetes and kidney disease and the importance of early detection and management of kidney disease.
Q: What is the link between diabetes and kidney disease?
A: Diabetes is the most frequent cause of chronic kidney disease, not only in the United States but in most industrialized countries. Kidney disease in people with diabetes is caused by multiple factors, including diabetic changes in the kidneys as well as vascular changes due to hypertension. People with diabetes have high glycemia, or blood glucose, which can damage the kidneys and lead to kidney disease.
When people are diagnosed with diabetes, they may already have hypertension. Hypertension is an additional risk factor for diabetic kidney disease because high blood pressure damages the kidneys, which may prevent proper function.
Q: What are the benefits of talking about kidney disease risk factors with patients who have diabetes?
A: Most of the risk factors for kidney disease in patients with diabetes can be modified. We can treat and manage them. However, like many other chronic diseases, kidney disease has very few early symptoms. For instance, a patient may have albuminuria, which is the earliest sign of kidney disease. It means that there is too much of the protein albumin in the urine, but a patient may not have any symptoms specific to the albuminuria.
The prevalence of kidney disease in the United States is about 15 percent, yet awareness of kidney disease is very low. Patients can have kidney disease for a long time without having symptoms or knowing that they have the disease. We found that many transplant patients and new dialysis patients had little awareness of their kidney disease and did not know what they could have done to help prevent or slow the disease before kidney failure.
It is especially important to talk to patients with diabetes about kidney disease risk factors because they are more than twice as likely to develop kidney disease than those without diabetes. By talking with patients who have diabetes about kidney disease, the disease may be diagnosed early, and patients can take steps to help slow its progression.
Q: Why is it so important to diagnose kidney disease in patients with diabetes as early as possible?
A: By diagnosing kidney disease as early as possible, we can treat the disease earlier, which means slowing disease progression. The end goal for treating kidney disease as early as possible is to prevent kidney failure, which is when the kidneys have lost most of their ability to function. By preventing kidney failure, you avoid end-stage renal disease, which is the stage at which dialysis or a kidney transplant is needed to survive.
Patients with diabetes who know they have kidney disease can
- avoid certain medicines, such as nonsteroidal anti-inflammatory drugs, which can worsen or accelerate kidney disease progression
- modify their diets to slow or prevent kidney disease from progressing
Diagnosing and managing kidney disease early can prevent complications, particularly cardiovascular complications. Many physicians and researchers are not aware that among people with diabetes, kidney disease doubles the risk for cardiovascular disease.
Beyond the positive health implications of diagnosing and treating kidney disease early, CDC has published studies demonstrating that diagnosing and treating the disease early to avoid kidney failure and other complications is cost effective.
Q: What are the recommended guidelines for kidney disease testing?
A: Kidney disease is diagnosed and tracked using two tests. One is a blood test, called serum creatinine, used to calculate the glomerular filtration rate (GFR), or kidney function, which assesses how well the kidneys are filtering blood. A GFR below 60 for at least 3 months indicates chronic kidney disease.
The other test used to diagnose and monitor kidney disease checks for albumin in the urine. Anyone with a urine albumin result above 30 milligrams per gram for at least two out of three albumin tests in a 3-month period is considered to have kidney disease. Physicians should be aware of the importance of the urine albumin test, because it is able to detect early kidney disease.
Guidelines recommend that anyone with one or more risk factors for kidney disease—people with diabetes, hypertension, or heart disease; those with a family history of kidney disease or diabetes; people older than 50 years; and those who smoke—be tested for kidney disease. Testing for kidney disease is inexpensive and easy and is critical to identifying and treating the disease early.
Q: How can health care professionals help to prevent or slow kidney disease from progressing in patients with diabetes?
A: It’s important for health care professionals to educate patients about their risk for kidney disease, how the disease might affect their health, what they need to avoid, and how they can modify their lifestyle to prevent or slow the disease. When patients understand their risks, they may be more likely to talk with their health care professional about getting tested for kidney disease and more aware of the importance of keeping their kidneys healthy.
In general, kidney disease progresses relatively slowly with few or no symptoms, so there is a very long window of opportunity to personalize and adjust treatment to a patient's situation. The first and most important way to prevent or slow kidney disease in people with diabetes, whether it’s type 1 or type 2 diabetes, is to manage blood glucose levels. Glucose levels should be monitored regularly. Another way to help prevent or slow kidney disease progression is by managing blood pressure. This is particularly important in patients with type 2 diabetes, who often have high blood pressure. Lifestyle changes and medications such as ARBs, or angiotensin receptor blockers, often play a key role in controlling blood pressure in people with diabetes.
Ultimately, the best way to prevent kidney disease is to prevent type 2 diabetes, because nearly 40 percent of people with diabetes will develop kidney disease.
Q: Is there anything else that health care professionals should know about kidney disease in people with diabetes?
A: The U.S. Department of Health and Human Services recently announced an important new kidney disease initiative called Advancing American Kidney Health. The initiative has three main goals—to reduce the number of Americans developing kidney failure, encourage home dialysis rather than treatment in dialysis centers, and increase the number of kidneys available for transplant.
This initiative is exciting because it recognizes kidney disease as an important public health issue and creates an official policy framework to improve kidney care in the United States. It aims to improve prevention and treatment, redesign dialysis to improve the quality of life among dialysis patients and increase their life expectancies, and create incentives for individuals to donate kidneys.