More than One in Four Adults at Risk for Kidney Failure

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Early screening and lifestyle changes can stave off life-threatening complications

HAVE YOU HAD your urine tested to see if there's protein in it? The National Kidney Foundation says you should, particularly if you have diabetes or high blood pressure; are overweight (especially around the middle); elderly; African American or Hispanic; or have a family history of heart attack, stroke, or kidney failure. Protein in the urine indicates compromised kidney function, and these groups are at greater-than-average risk for that problem.

High blood pressure alone, which affects some 50 to 60 million Americans, is the second-leading cause of kidney failure in the U.S. And diabetes, which afflicts about 15 million Americans, is the leading cause. Combined, those two conditions account for more than 60 percent of all new cases of kidney failure every year.

Unfortunately, many people with diabetes or high blood pressure don't even know they have those conditions, let alone an increased risk for kidney disease. People often aren't diagnosed with diabetes until they have had it for many years--at which point kidney disease, which is irreversible, can be quite far along. Furthermore, a third of people with high blood pressure aren't cognizant of that fact. And even mild forms of high blood pressure can damage the kidneys over time.

The magnitude of the problem is such that of the millions of Americans with kidney disease, 260,000 have progressed to out-and-out kidney failure and have to be hooked up to dialysis machines to filter out waste that their kidneys can no longer handle. Some 40,000 people are currently waiting for kidney transplants to extend their lives, but only about 11,000 kidneys are transplanted annually due to a shortfall in donated organs. The upshot of chronic kidney failure: nearly 50,000 deaths a year.

Many lives could be saved, however, if a standard test to detect kidney damage--a simple urine analysis--were administered more routinely. The test looks for a protein in the urine called albumin. If it's there, it's a sign that the kidneys are "leaky," explains Garabed Eknoyan, MD, immediate past president of the National Kidney Foundation.

Think of the kidneys, two fist-sized organs in your back that are located just below the rib cage, as made of a material akin to fine cheesecloth, says Lori Gregoire, a registered dietitian who specializes in renal (kidney) disorders at the New England Medical Center. Every day, 800 cups of fluid flow through them. Most of them get recycled, but approximately eight cups leave the body as urine. If the consistency of the kidney "cloth" is not just so, it cannot do its filtering job properly, leaking some things into the urine that should have remained in the body.

One of the things the kidneys are supposed to keep in the body is protein, so if it is detected in urine, it means that the kidney "cloth" has lost its proper "texture" and that kidney damage has occurred. At that point, the patient should be referred to a nephrologist (kidney specialist), who will work in conjunction with the individual's primary care physician to coordinate treatment (see box).

It's amazing how many people in high-risk groups do not get tested for protein in the urine, Dr. Eknoyan says. For instance, he points out, while most people with diabetes have their blood cholesterol checked, "only about 30 to 40 percent of them are having their urine checked for protein. That's not good medicine."

Anyone not in a high-risk group should get tested at least once a year, too, Dr. Eknoyan says. (In the same visit, your doctor can check your blood pressure to screen for hypertension and measure the level of sugar in your blood to see if you have diabetes.)

Measuring the level of protein in the urine is important not just for detecting kidney problems. It's also important for identifying an increased risk of cardiovascular complications. Those with diabetes and high blood pressure whose kidneys are leaking protein are much more apt than their counterparts with normally functioning kidneys to suffer a fatal heart attack or stroke (even in the absence of overt kidney disease). In fact, many more people with compromised kidney function die of one of those events long before their kidneys give out. Once the kidneys start to "go," metabolic changes in the body that pave the way for heart disease begin to accelerate.

To protect your kidneys...
One of the most important things you can do to protect your kidneys is lose excess weight, if necessary. Losing weight reduces the severity of diabetes and hypertension, the two leading causes of kidney failure, and helps prevent those conditions in people who have never had them.

People with diabetes and high blood pressure should also make sure to follow the diets prescribed for them and faithfully take their medications. People with hypertension who already have kidney disease are often prescribed drugs called ACE inhibitors, which appear to directly help the kidneys and keep down blood pressure.

Some nephrologists believe that following a low-protein diet helps reduce the work load of the kidneys in people with rather advanced renal disease. New England Medical Center nephrologist Andrew Levey, MD, reports that reduced-protein regimens are thought to lighten the kidneys' filtering burden at the point where kidney function is at least half gone.

If your nephrologist is one of those who believe in the efficacy of a reduced-protein diet (as Dr. Levey is), he or she may want you to work with a registered dietitian to limit the amount of protein in your daily eating plan. The typical American diet is quite protein-rich, and many Americans average twice as much protein as they need on a daily basis.

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