Leslie Spry, MD
Leslie Spry, MD, a kidney specialist in Lincoln, Nebraska, and a spokesman for the National Kidney Foundation. He is a member of the Public Policy and Public Education committees of the National Kidney Foundation, www.kidney.org.
Nine out of 10 Americans with kidney disease don’t know they have it — a huge problem, because the key to managing kidney disease is to catch it early. Instead, millions of Americans are placing themselves at risk for kidney failure, which has been increasing in the US at a rate of 2% a year.
Our kidneys contain a vast network of microscopic blood vessels that filter waste products from the bloodstream and then flush them out of the body in the form of urine. After age 40, we experience a natural decline in filtering capacity of about 1% per year.
Chronic kidney disease: A growing number of Americans are developing chronic kidney disease, in which loss of kidney function occurs at a much faster rate — until the kidneys become so damaged that dialysis (a procedure that flushes waste, salt and excess water from the body and helps maintain a safe level of such chemicals as potassium, sodium and bicarbonate in the blood) or a transplant is needed to survive.
Recent studies found that 13% of the US population — about 26 million people — now have chronic kidney disease, up from 10% a decade ago. Reasons: A rise in the number of Americans with diabetes — one of the major causes of chronic kidney disease… and the growing percentage of the population made up of ethnic groups who are especially vulnerable to kidney disease, including African Americans, Hispanics and Native Americans. Aging by itself doesn’t cause kidney disease. Aging plus a condition, such as high blood pressure or diabetes, does.
Chronic kidney disease produces no symptoms until it is far advanced, so it’s important to get regular screenings of your kidney function. Kidney screens are a standard part of annual physical exams, so if you’re getting regular yearly checkups, you should have a good idea of your kidneys’ health. If you don’t get regular checkups, however, it’s important that you see a doctor annually for a kidney screen — especially if you have one or more of these five risk factors…
According to the National Kidney Foundation, 30% of adults tested who had any of these risk factors had kidney disease. You should also get a kidney screening right away if you notice any of these potential symptoms of kidney disease — urine that is dark-colored, foamy, bubbly or contains blood… having to urinate more often than usual, especially at night… urinating less often or in smaller amounts… persistent swelling of the legs, ankles, feet, face or hands that lasts more than a week… signs of anemia (caused when poor kidney function results in a lack of red blood cells), including fatigue, shortness of breath, feeling cold all or most of the time, dizziness or trouble concentrating… nausea, especially in the morning, that lasts several weeks… generalized itching of the skin that lasts several weeks… bad breath.
Kidney disease can usually be spotted with two simple screening tests that can be done in a lab or your doctor’s office.* Someone is considered to have chronic kidney disease if both tests come back positive when repeated over a three-month period. If your tests show that your kidneys are fine, it’s still important to repeat the tests once a year.
Test 1: A blood test for serum creatinine — a naturally occurring waste product. Normal levels are 0.5 to 1.1 milligrams per deciliter (mg/dL) for women and 0.6 to 1.2 mg/dL for men. Since creatinine levels can fluctuate, a positive reading will be followed by an additional test. Lab technicians then use your serum creatinine levels to calculate your glomerular filtration rate (GFR), a measure of how well the kidneys filter waste from the bloodstream. Healthy adults tend to have a GFR of about 140, and anything above 90 is considered normal. A GFR between 60 and 89 signals some kidney damage, but you are not yet terribly sick. A GFR of less than 60 is a sign of kidney disease, while a GFR below 10 signals imminent kidney failure.
Test 2: A urine test for albumin, a protein that leaks into the urine of people with damaged kidneys. Since urinary tract infections and certain illnesses can cause a temporary rise in albumin levels, it’s important to check this level again if the test returns positive.
If your kidney screen shows that you have kidney disease, the next step is to deal aggressively with any treatable risk factors you might have. The two most important are high blood pressure (hypertension) and diabetes. High blood pressure damages all of the body’s blood vessels, including the tiny capillaries in the kidneys.
Drugs called ACE inhibitors, such as enalapril (Vasotec) or lisinopril (Prinivil), and angiotensin II receptor blockers (ARBs), such as losartan (Cozaar) and irbesartan (Avapro) — which can be used separately or together — are the two classes of drugs prescribed to lower blood pressure in people with kidney disease. Both have been shown to delay and even reverse deterioration of kidney function. The goal is to get blood pressure down to 130/80 mmHg or less — and to 125/75 mmHg or better if a large amount of protein is being spilled into the urine.
Type 2 (adult onset) diabetes is the biggest cause of kidney failure. Reason: High blood sugar levels cause scarring of the blood vessels in the kidneys. For this reason, people with chronic kidney disease need to be especially scrupulous about keeping their blood sugar under control by watching their diets and monitoring their blood sugar on a regular basis. The goal is to have a hemoglobin A1C (a test given every several months) reading between 6 and 7, which indicates good diabetic control.
If a person can reach these goals, it’s possible to delay and even reverse kidney disease.
To look after your kidneys…
*If you live near a branch of the Kidney Early Evaluation Program (KEEP) — a free community-based health program provided by the National Kidney Foundation — you can get a free screening. You must be at least 18 years old and have high blood pressure, diabetes or a family history of kidney disease. For more information, visit www.kidney.org and type “KEEP” into the search box, or call 800-622-9010.