Chronic Kidney Disease: A Silent, Yet Lethal Complication of Diabetes
Diabetes affects the tiny blood vessels in the kidneys called glomeruli, initiating the development of chronic kidney disease. This quiet process decreases the filtering efficiency of the bean-shaped organs and may eventually result in kidney failure and dialysis.
Chronic kidney disease, or CKD, is a silent killer and is most commonly caused by diabetes. Currently, an astounding twenty million people in the United States suffer from CKD and while there is no known cure, early detection and treatment slows the progression to kidney failure. The National Kidney Foundation recommends that all diabetics undergo simple testing to screen for CKD – but your doctor may not know about this lifesaving protocol.
Physicians have long understood that diabetes affects almost every organ system in the body, including the kidneys. Normal kidneys filter the blood, removing toxins, waste products, and excess fluids while controlling blood levels of sodium, potassium, phosphorus, and calcium. In addition, the kidneys produce chemicals that regulate blood pressure, aid in the production of red blood cells, and maintain bone structure.
Diabetes affects the tiny blood vessels in the kidneys called glomeruli, initiating the development of chronic kidney disease. This quiet process decreases the filtering efficiency of the bean-shaped organs and may eventually result in kidney failure and dialysis. Both the American Diabetic Association and the National Kidney Foundation recommend screening guidelines for diabetics and other groups at risk for CKD, but you should know that not all physicians are aware of them.
A recent study released in the American Journal of Kidney Diseases concluded that primary care doctors, such as family physicians and general internists, often overlooked the diagnosis of CKD and were less confident regarding follow-up studies for those identified as having the disease. Organizations such as the American Academy of Family Physicians and the National Kidney Foundation strive to instruct medical providers regarding CKD, but patient education is also vital. So what is CKD and how is it detected?
Most people with early CKD have no symptoms, but as the disease progresses, diabetics may notice weakness, decreased appetite, frequent urination during the night, swelling of the feet and ankles, and difficulty thinking clearly. Other symptoms can include nausea, vomiting, a decreased need for diabetes medication, and persistent itching. In addition, certain ethnic groups, including African Americans and Hispanics, have an increased risk for CKD as well as an increased risk of developing diabetes.
In 2002, the National Kidney Foundation released new recommendations for the detection and treatment of chronic kidney disease. The condition, formerly known as renal insufficiency, is now defined as kidney damage and/or decreased filtering efficiency lasting for three or more months.
Kidney damage is determined by measuring a protein called albumin, a substance that is normally present in the urine in minute amounts. The American Diabetic Association, or ADA, recommends that this simple dipstick test for microalbumin should be checked yearly in all type II diabetics beginning at the time of diagnosis.
Many people fail to recognize the early symptoms of diabetes, delaying the diagnosis for months or years during which time the kidneys and other vital organs silently suffer. Studies show that one third of those with diabetes test positive for albumin. In addition, a routine urinalysis may detect evidence of further kidney damage by revealing blood or other proteins.
The filtering efficiency of the kidneys is an estimated measurement called the glomerular filtration rate, or GFR, and should be checked at least once a year. This critical value is calculated from a complex formula based on age, sex, race, and blood creatinine level. Thankfully, the GFR is now often included in routine blood test panels.
Specific treatment of CKD depends on the stage, but the goal is to slow the progression to stage five. For diabetics, controlling glucose levels is critical. Ideally, hemoglobin A1C levels should remain under seven. Hypertension is another leading cause of CKD and is considered by some researchers to be the major indicator in predicting which diabetics will develop kidney complications. A blood pressure of 130/80 or less is considered normal for those with diabetes and it is estimated that over 70 percent of adult diabetics have hypertension.
Two classes of blood pressure medications are recommended for the treatment of diabetics with hypertension. Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB) not only control blood pressure, but also are recommended by the ADA for the treatment of kidney disease as evidenced by albumin in the urine.
Diabetes and hypertension are both considered risk factors for the development of cardiovascular or heart disease, including heart attacks and stroke. However, CKD is a major risk factor for heart disease as well. ACE inhibitors can reduce severe cardiovascular disease while lowering blood pressure and decreasing urine albumin.
In addition, a low protein diet may be indicated and you should avoid medications such as aspirin-related pain relievers that can injure the kidneys. When CKD progresses to stage three or beyond, the treatment and management become more complex and many primary care physicians will refer to a nephrologist, or kidney specialist, at this point.
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"Chronic Kidney Disease: A Silent, Yet Lethal Complication of Diabetes"
Dr. Thomas has been board certified by the American Academy of Family Physicians since 1990. She is a member of the American Medical Association and the North Carolina Medical Society. She is a columnist for the Washington Daily News in Washington, N...