PREVENTING, MINIMIZING, OR DELAYING KIDNEY FAILURE

"I'm sorry, but your kidneys are beginning to fail..." If you hear those words, what do you do next? Knowing that nephropathy, kidney failure, is a frequent complication of diabetes, do you sit and wait to get worse, or do you act? What can YOU do to prevent, minimize, or slow kidney failure?

Before we relate specifics, a review of the kidney, and why it fails. Your kidneys are your body's blood-cleansing devices, millions of tiny tubes (the glomeruli) designed to filter wastes, products of normal cell metabolization, from the blood into the urinary system. Extended periods of high blood sugar, as follow untreated or poorly-managed diabetes, can inflame, scar, or obstruct the filters, leading to permanent loss of function. If enough of the kidney's blood-cleansing function is lost (measurements of kidney function remaining are described in the accompanying article "Kidney failure, dialysis, and transplantation"), dialysis or kidney transplantation become necessary to sustain life.

The traditional test for protein spillage into the urine (clear sign of kidney disease) has been the proteinuria "dipstick test." Although still widely used, it has been made obsolescent by the much more sensitive microalbuminuria "24-hour urine test," which is capable of detecting kidney disease at much earlier stages. Some doctors have suggested that approximately ten years after diagnosis (and sooner where indicated) every diabetic should have a microalbuminuria test, to check for the early stages of kidney disease.

The Diabetes Control and Complications Trial (DCCT), a large, long-term, federally-funded study of the relationship between diabetes control and the onset of complications, found that there was a tight statistical link between quality of diabetes control and ramifications such as heart and blood vessel disease, diabetic eye disease, and diabetogenic kidney failure. The tighter your control, the less chance you will experience the complications. (Note the linkage is not absolute; you can do your best and still face these ramifications.)

The DCCT's findings are not mysterious. High blood sugar causes complications; and the better job you do of keeping your blood glucose numbers down where they should be, the less your chance of developing conditions such as nephropathy. The importance of this cannot be overstated: Good self-management is the BEST way to cut the risk of any diabetes complications.

There are other things you can do to cut the risk. Some of them come under the heading of "healthy lifestyle." Nicotine, the narcotic active ingredient in tobacco, is a vasoconstrictor, raising blood pressure, stiffening capillaries, and making it harder for the kidneys to filter wastes.

Urinary tract infections need prompt treatment, to limit the damage they can do to already strained kidneys. Tell your doctor promptly, if you think you have such an infection.

Excessive obesity both raises blood pressure and increases insulin resistance. Keeping your weight at or below your recommended level helps in general, and the resultant blood pressure drop is good for your kidneys.

Heart specialists have known for years that high levels of stress can be damaging. Excessive stress, driving up blood pressure, can harm the kidneys by raising fluid pressure, further straining already weakened filter networks. Stress reduction is part of a healthy lifestyle.

Generalized high blood pressure (hypertension), whatever its cause, strains kidneys weakened by diabetes. The kidneys also maintain a fluid pressure of their own, the better to perform their cleansing job. Partially controlled by blood pressure, kidney fluid pressure is also dependent on the health of the organ. Any scarring or occlusion of the filters will drive up fluid pressure (kidney disease often raises blood pressure as well), further straining damaged filter networks. This can easily set up a vicious cycle, hastening complete destruction of kidney function. But there is treatment.

Angiotensin-Converting Enzyme ("ACE") inhibitors like Captopril (trade name Capoten), nominally blood pressure medications, have been successfully used to reduce the rate of kidney failure in type I diabetics who show early stages of kidney damage. The ACE inhibitors act directly to relax and open up weakened kidneys, lessening the strain and slowing, sometimes almost halting, the rate of failure. Even when the individual's blood pressure is within normal range, ACE inhibitors can make a tremendous difference, reducing fluid pressure, allowing healing, and delaying the onset of End Stage Renal Disease, that point at which dialysis or transplantation becomes necessary.

Although the tests that led to Captopril's FDA approval for treatment of kidney disease were performed on insulin- dependent diabetics, most doctors believe type II diabetics who show signs of kidney failure also would benefit from use of Captopril or other ACE inhibitors. Please note that ACE inhibitors are not safe for pregnant women.

Other blood pressure medications, the "beta blockers," and the "calcium channel blockers," confer some of the same benefit, and are "second choices" if there is an allergy or other consideration. Sources agree that prompt adoption of a treatment regimen that includes ACE inhibitors, as soon as possible after diabetic kidney disease is detected, can make a significant difference. Ask your doctor about ACE inhibitors.

There are also medications you should avoid, if you have any trace of kidney failure. Certain classes of over- the-counter pain medications can cause kidney damage in non- diabetic individuals. Ibuprofen and Aleve are two of this potentially dangerous group. For minor "aches and pains," most health professionals now recommend Acetaminophen (as in Tylenol), which is far safer on the kidneys. Be sure to discuss this with your doctor.

Wesley Wilson, MD, of the Western Montana Clinic in Missoula, Montana, reminds us:

If there is any kidney disease, the fewer drugs you take, the better. Many of the medications we use for pain or other conditions can increase kidney damage, or their effect can be harder to predict, because the drug may be retained by the poorly functioning kidneys. Certainly do not take any drug unless you need it, and be sure to discuss your choice of nonprescription drugs with your physician. In addition....other measures felt to be important in preserving kidney function include avoiding dehydration, reducing dietary protein, and carefully controlling both blood glucose and blood pressure.

Dr. Wilson brings us to the next point. Many clinicians believe that protein restriction will help reduce the rate of kidney decline, once kidney disease is present. Traditional "kidney failure" diets featured radical restrictions on protein intake, but dietitian Mimi Moore, RD, writing in VOICE Vol. 11, No. 1 (Winter 1996), stated the recommendation that protein be decreased is not as severe as it was in the past. "Today," (she stated), "for a renal diet, the target should be about .8 gram of protein per kilogram of body weight, which is about the American adult recommended amount."

Ms. Moore went on to state that the average American eats far more than the recommended adult amount of protein, and that keeping to the limit, along with other frequently- exceeded limits such as those on potassium and sodium, is part of a healthy lifestyle.

What about the other part of a "healthy lifestyle"-- exercise? Ramesh Khanna, MD, Professor of Medicine, Division of Nephrology, University of Missouri Hospital and Clinics, states that once renal failure is detected, the patient should continue the physical activities to which he/she is accustomed. "Do not let renal failure slow you down," he states. He goes on to state that as long as no heart problems are present, you should be as active as you can. Of course seek medical supervision for such an exercise program.

This is in marked contrast to the exercise possibilities open to the kidney patient who has received a transplant. As long as general health and immunosuppressive regimes are maintained, transplant patients are as capable of athletic achievement as are those with two healthy kidneys.

There is a lot of disagreement among doctors over the specifics of what will prevent kidney failure. So much is genetics; more may be environment, or other factors we are not yet aware of. Other than "keep your diabetes under the best possible control, and live a healthy lifestyle," we can offer little advice about prevention. The manual THE PREVENTION AND TREATMENT OF COMPLICATIONS OF DIABETES MELLITUS, published (1991) by the Centers for Disease Control, states: "At present, strategies for preventing diabetic nephropathy must be viewed as limited in their effectiveness, since the exact pathogenic factors responsible for this condition are unknown."

Once kidney disease is diagnosed, however, a great deal can be done to retard its progression, and sometimes interventions such as described above are sufficient to keep the need for dialysis or transplantation well at bay. Current statistics suggest up to four out of every ten diabetics may experience kidney disease. With considerations such as described in this article, many of these individuals should be able to avoid End Stage Renal Disease.

If you do your best and still experience kidney failure, it is not time to despair. Whether you choose transplantation, or one of the forms of dialysis, the outlook is good and getting better all the time.