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Deadly Kidney Disease Is On the Rise

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Do you have it and not even know it?

Even if you feel fine right at this moment, your kidneys could be gradually failing. New finding: Nearly six in 10 Americans will develop kidney disease in their lifetimes, according to a recent analysis published in American Journal of Kidney Disease. In comparison, lifetime risk for diabetes, heart attack and invasive cancer is approximately four in 10.

As a result of this and other findings, the National Kidney Foundation called for health-care professionals to screen patients in specific high-risk groups for chronic kidney disease (CKD)—those age 60 or older and those with high blood pressure or diabetes—by adding a simple urine albumin test for kidney damage to annual physical ­examinations.

My advice: Get checked even sooner, at about age 50, and then yearly after that. If you have been diagnosed with diabetes or hypertension, then you should get tested annually regardless of your age. If your doctor finds any sign of impairment, get a referral to a nephrologist to see if anything should be done.

Here’s what else you need to know now about CKD…

A Disease on the Rise

CKD is the result of damage to the kidney’s one million-plus filtering units (kidney nephrons). This damage impairs the body’s ability to remove wastes as well as to do many other functions that the kidney does, such as regulating the amount of fluid in your body and the amount of critical chemicals, including sodium, potassium, calcium, phosphate and more. Typically there are no symptoms until 75% to 80% of kidney function is lost. At that point, eventual kidney failure is likely, with dialysis and/or a transplant being the only treatment options.

Unfortunately, kidney disease is on the rise. In the mid-1980s, about 70,000 Americans were getting dialysis for kidney disease. In the years since, the number has risen to about 450,000, a sixfold increase. And millions of people with CKD aren’t even aware that they have it.

The number of people with kidney disease is rising partly because the American population is aging, and older people get more chronic diseases, including CKD. There also has been an enormous increase in diabetes, which is the leading cause of CKD, followed by high blood pressure. More than one-third of people with diabetes and more than 20% of patients with high blood pressure show signs of kidney damage.

Smoking, obesity and high cholesterol also increase the risk.

You can reduce damage and slow the progression of CKD with medications and by treating the conditions that cause it. Once the disease has ­progressed, your options are ­limited—and the risks are high. Among dialysis patients, there is a 15%-to-20% death rate every year. Worsening kidney function increases the risk of dying from cardiovascular disease. It also can lead to bone weakness, anemia and other ­complications.

It’s critical to get diagnosed while the kidneys still are working well.

Simple Tests

Most cases of CKD can be detected with a few basic (and inexpensive) tests. If your doctor finds any sign of impairment, a referral to a nephrologist is a good idea to determine what is causing the kidney disease.

• Serum albumin. This is the test that the National Kidney Foundation recommends be added to the annual physical for anyone over age 60. Serum albumin is a protein found in the urine of patients with CKD. The most commonly used way to measure urine albumin is by dipping a test strip in the urine. Although this is a good screen, it does not pick up a low-level increase in the urine albumin level.

A better test is the microalbumin test (also called the albumin/creatinine ­ratio test). It can be done on a single urine specimen sent to any laboratory. This is the best test to determine the urine albumin level. The presence of albumin in the urine usually indicates kidney damage. An increase in the urine albumin level often is the first sign of kidney damage from diabetes. It also can be due to hypertension and other conditions. A reading of more than 30 milligrams (mg) of albumin per 1 gram (g) of creatinine is a sign of CKD.

• Serum creatinine. A product of normal muscle metabolism is creatinine. Because your creatinine is produced at about the same level every day and filtered by the kidneys, it has been used to estimate kidney function. Elevated levels might mean that you have kidney disease. In young men up to age 40, normal levels are 0.6 mg per deciliter (dL) of blood to 1.2 mg/dL. In young women up to age 40, 0.5 to 1.1 mg/dL is the normal range. Normal serum creatinine values decline as we age.

Caution: Creatinine alone is not a perfect measure of kidney health. If your creatinine is elevated, you will need additional tests to confirm—or rule out—CKD. For example, your creatinine can rise due to dehydration.

• Glomerular filtration rate (GFR). This is a measure of kidney function estimated from your creatinine level and other factors, including age, sex and race. The GFR gives a more accurate reflection of kidney function than the serum creatinine test alone. A healthy 50-year-old typically will have a GFR of about 80 milliliters per minute (mL/min) to 100 mL/min. A reading of 60 mL/min or lower that persists for at least three months is a sign of CKD.

Next Steps

There isn’t a cure for CKD, and the damage can’t be reversed. However, you can slow the rate at which the disease progresses and possibly avoid dialysis/transplantation. Important…

• Strict glucose control. Since most cases of CKD are caused by diabetes, it’s essential to maintain healthy blood sugar levels. Elevated glucose damages the blood vessels that are used by the kidneys to filter wastes. If you have diabetes, follow your doctor’s instructions about when and how often to test your blood sugar. Eat a healthy diet…exercise most days of the week…and take medications as instructed.

• Better blood pressure. The same factors that are good for diabetes (and your heart) also will improve your blood pressure.

Important: Even if your blood pressure is normal or just slightly elevated, your doctor still might prescribe a drug called an ACE inhibitor (such as Capoten or Vasotec) or an angiotensin II receptor blocker (such as Cozaar or Diovan) if you have elevated urine albumin levels. Blood pressure–lowering medications can slow the progression of CKD by lowering urine albumin levels, even if your blood pressure is normal.

• Less salt. Limit your daily salt consumption to 1,500 mg (about two-thirds of a teaspoon) or less if you have high blood pressure, take a diuretic or have swelling in your legs.

• Not too much protein. Animal studies indicate that a high-protein diet causes more serious illness in those with kidney disease. It’s not clear whether it has the same effect in humans—but moderation makes sense.

You don’t have to follow a very-low-protein diet—you just don’t want too much protein. In my view, if you have CKD, it is likely that a protein intake of up to 56 g/day for men and 46 g/day for women is safe. Ask your doctor for a referral to a dietitian. He/she will help you calculate how much protein you need.

• Be careful with painkillers. People who regularly take large doses of painkillers—such as aspirin, ibuprofen or acetaminophen—have an elevated risk for CKD. If you depend on these medications—to control arthritis, for example—talk to your doctor. This is particularly important if you already have been diagnosed with CKD.

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Source: Robert C. Stanton, MD, principal investigator in the section on vascular cell biology and chief of the nephrology section at Joslin Diabetes Center and Joslin Clinic. He is associate professor of medicine at Harvard Medical School and a staff member at Beth Israel Deaconess Medical Center, all in Boston.

Date: March 15, 2014 Publication: Bottom Line Personal
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