How to prevent this silent threat

How healthy are your kidneys? If you’re like most people, you don’t know.

Surprising new finding: An estimated 20 million adults in the US have chronic kidney disease (CKD) — but among them, less than 12% of the men and less than 6% of the women are aware of it.

Even fewer people realize that CKD, like high blood pressure, diabetes and elevated cholesterol levels, leads to an increased risk for heart disease and stroke.

What you can do: If you are at increased risk for CKD, getting regular tests to ensure that your kidneys are working properly is just as important as having your blood pressure, blood sugar (glucose) and cholesterol levels checked periodically. Among those at increased risk: People with high blood pressure, diabetes or a family history of kidney disease in a first-degree relative (parent or sibling). CKD also is more common in people over age 60.

WHAT CAN GO WRONG

It used to be thought that kidney function — the removal of waste products and excess water from the bloodstream — slowed down naturally as a result of aging. But now kidney specialists (nephrologists) know that loss of kidney function occurs more rapidly in people with high blood pressure and diabetes. Both conditions damage blood vessels in the body, including those in the kidneys.

Other illnesses — including autoimmune disorders, such as lupus, as well as infections, including hepatitis B and hepatitis C — can damage the kidneys, too. Some drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDs), certain antibiotics and contrast agents used for angiography or computed tomography (CT) scans, also can harm the kidneys.

DETECTING KIDNEY DISEASE

In the early stages, kidney disease usually causes no symptoms. By the time symptoms do occur — typically fatigue, weakness and an overall feeling that you are not well — the decline in kidney function is often advanced and cannot be reversed.

Some CKD patients go on to develop kidney failure, requiring treatment with dialysis (using a machine to perform most functions of the kidneys) or a kidney transplant. That’s why screening (with blood and urine tests) should be part of your regular physical exam if you are at increased risk for kidney disease. Most important tests…

  • Albumin is the most abundant protein in the blood. If the kidneys are working properly, they return albumin to the bloodstream as it passes through the kidneys’ microscopic filtering units, known as glomeruli. Albumin in the urine suggests that the kidneys have sustained damage. Important: A standard urinalysis is not sensitive enough to detect very low levels of albumin. A special test, called a microalbumin test, is required.

  • Creatinine, a by-product of normal muscle metabolism, is one of the waste substances removed by the kidneys. Doctors use the level of creatinine in the blood to estimate the glomerular filtration rate (GFR), an indication of how efficiently the kidneys are doing their job. A GFR level of less than 60 units is considered abnormal.

    • TREATING THE ROOT CAUSE

    The goal of treatment for kidney disease is to manage the underlying condition that caused the disease — most often high blood pressure or diabetes. Effective treatment can slow the decline in kidney function, treat complications of that decline (such as anemia and malnutrition) and reduce the risk for heart disease and stroke.

    Treatments for underlying conditions that cause or worsen kidney disease…

  • High blood pressure. If you have kidney disease, your target blood pressure is below 130/80 mmHg — lower than the target for other people with hypertension (below 140/90 mmHg). Some blood pressure drugs have been shown to be particularly useful in preserving kidney function. When albumin is present in the urine, good choices are angiotensin-converting enzyme inhibitors, such as enalapril (Vasotec) and benazepril (Lotensin)… or angiotensin receptor blockers, such as candesartan (Atacand) and losartan (Cozaar).

    • Caution: If you take a diuretic for hypertension, it is especially important to receive routine kidney function tests — these drugs can cause dehydration, which in turn can lead to complications that result in kidney failure.

  • Diabetes. Good control of blood sugar reduces the risk for kidney damage and other diabetes complications. Glipizide (Glucotrol) is often preferred because it is not broken down by the kidneys. Metformin (Glucophage), a popular diabetes drug that is broken down by the kidneys, may not be recommended for people with relatively advanced kidney disease.

    • PROTECTING THE KIDNEYS

    People with CKD also should take special precautions with…

  • Painkillers. This includes over-the-counter NSAIDs, such as ibuprofen (Motrin) or naproxen (Aleve) — especially if used regularly, these drugs may hasten kidney deterioration. Acetaminophen (Tylenol) is usually a better option for people with CKD.

  • Dyes injected for contrast during radiographic procedures, such as angiography and CT scans. These may injure kidneys that are weakened by disease. When arranging these tests, tell your doctor if you have CKD.

  • Surgery and anesthesia, which may affect kidney function, require special precautions, such as careful monitoring of fluids. If you have CKD, tell your surgeon.