By Eli A. Friedman, MD

Diabetes is a disease that can destroy lives, disrupt families and is the number one cause of kidney failure worldwide. The key defect in people with diabetes is that they have an absence (type 1 diabetes) or a decreased ability to use (type 2 diabetes) the vital hormone insulin. Produced by the pancreas, insulin allows glucose (asimple, but essential form of sugar) to enter cells where it releases energy. People with diabetes build up glucose and fats in their blood resulting in injury to small and large blood vessels and the major organs they nourish. What makes diabetes so horrific is that it can incite many complications including blindness in adults, amputations of limbs, heart disease and strokes, urinary bladder paralysis and embarrassing uncontrolled diarrhea.

One out of three white babies, and two out of three black babies born in 2003 will develop diabetes, explaining why the United States spends $132 billion each year for its management as reported by the Centers for Disease Control and Prevention (CDC). Other eye-opening statistics list diabetes as the fifth leading cause of death and, what is of prime interest to the American Association of Kidney Patients (AAKP), the top cause of end-stage renal disease (ESRD). In fact, in its 2003 report, the United States Renal Data System (USRDS) notes that 44 percent of all newly reported ESRD patients had diabetes, while an additional seven percent had diabetes that was not reported. Furthermore, when adding the 10.5 percent of newly treated ESRD patients who “developed” diabetes (meaning the diagnosis was confirmed) during their first year of treatment, the grand total is 61 percent for the proportion of all U.S. kidney failure patients who suffer diabetes. It is not a surprise that AAKP, Medicare, Medicaid and all healthcare providers place diabetes on center stage.

After you have thought about the bad news surrounding diabetes, there is reason for being hopeful that things are about to get much better. First, the complications of diabetes can be delayed, and in some patients totally prevented, by treating the hyperglycemia (high blood glucose) and hypertension (high blood pressure) that are fellow travelers, and nearly always present. Second, we have truly effective comprehensive treatment plans.

National surveys discovered that as many as one-half of diabetic Americans are undiagnosed, meaning their complications are progressing without their knowledge. The typical patient with new onset diabetes complains of blurred vision, skin and vaginal infections, unusual fatigue, tingling sensations in the fingers or toes or numbness of the feet. In most diabetic people, however, the disease is detected during a medical evaluation for some other condition. For example, when hospitalized for a hip fracture or a heart attack, high blood glucose levels are found in routine chemical testing. Or, after a minor foot cut or abrasion, healing does not occur signaling that something is wrong.

Our understanding of diabetes was made possible when Frederick Banting and Charles Best extracted insulin from the pancreas of dogs. Banting and Best injected insulin into dogs without a pancreas and corrected the chemical problems found in diabetic people. Next, they demonstrated that in patients whose pancreas failed to make insulin (previously called juvenile and now type 1 diabetes) insulin treatment was life-saving. But type 1 diabetes accounts for less than five percent of diabetic ESRD patients, the majority of whom suffer the more common form of diabetes formerly called non-insulin-dependent diabetes, now termed type 2 diabetes. Type 2 diabetes usually starts as a chemical disorder in which the insulin that is produced by the pancreas does not work properly in lowering the blood glucose (insulin resistance). After ten or more years, the pancreas is unable to make enough insulin to overcome the resistance and the level of blood glucose rises.

Until as recently as ten years ago, type 2 diabetes was considered a disease of adults, usually appearing after the age of 40 (called maturity onset diabetes). Today, type 2 diabetes is regularly diagnosed in adults in their twenties as well as in teenagers and children. There is a direct link between the exploding rate of diabetes (pandemic is the term for an epidemic that hits almost everyone, everywhere) and the reality that most of us are fat and getting fatter. Indeed, more than 60 percent of Americans are overweight and the CDC found that while three and a half percent of Americans of normal weight have diabetes, 13.5 percent of overweight Americans have diabetes. Risk factors for diabetes, other than getting fat, include getting old (the good news is that you made it), and being black, native American or Hispanic.

The onset of kidney disease in diabetic people is announced by the finding of protein in the urine. Healthy people have no more than 30 mg of protein in their daily urine. Early in the course of diabetic kidney disease, the amount of urinary protein may be so small (microalbuminuria) that it is not detected by the usual dipstick test. Nevertheless, when discovered, microalbuminuria is a call to arms and, as advised by the American Diabetes Association (ADA), one of the classes of drugs termed “Renoprotective” should be started to slow the progress of diabetic kidney disease. Many clinical trials support the use of angiotensin converting enzyme inhibitors (ACEi) like ‘enalapril’ or ‘lisinopril,’ as well as angiotensin receptor blockers (ARBs) like ‘losartan’ as effective means of delaying ESRD. Surprising in multiple clinical trials is the finding that treatment with ACEi or ARBs, both drugs for high blood pressure, are beneficial in diabetic people with protein in their urine and normal blood pressure. The ADA advises that every diabetic person with urinary protein should be receiving one of these drugs.

Therefore, message number one is that high blood pressure in diabetic people must be treated, and the presence of protein in the urine in amounts above normal is reason to start giving ACEi or ARBs. Frequently, one, or even two, drugs for hypertension are not enough to lower the blood pressure to a target of 135/75 mmHg as advised by the ADA, and other drugs such as diuretics, beta blockers and calcium blockers are added to the treatment program. There is no “one size fits all” plan for treating the hypertensive diabetic patient. What usually happens is that by trial and error, a drug combination that works in a specific patient is designed and learned by the patient.

Message number two is that a high blood sugar should not be tolerated. To control glucose levels, meaning to survive with diabetes, demands a tricky balancing act of the “correct” diet, exercise, oral drugs and in some patients, injected insulin. Getting to a proper balance means that the patient must test blood glucose level, an expensive, and unpleasant component of diabetes care in which a skin puncture is performed to get a blood sample for glucose measurement. Checking the blood glucose can be done as rarely as once every two or three days for a stable patient not treated with insulin, to as frequently as six times-a-day for hard to control insulin treated patients. The desired target range for blood glucose is 80 to 120 mg/dl before meals and 100 to 140 mg/dl at bedtime. A good indicator of proper overall glucose control is the glycohemoglobin or hemoglobin A1c (HbA1c) level which in normal people is five to six percent and in poorly regulated diabetic people can go as high as 20 percent. The ADA proposes striving for an HbA1c of less than seven percent. In practice, getting below eight percent is often difficult for patient and doctor.

Marvelous “Star Wars” technology has eased the burden of accurate glucose monitoring, especially needed when insulin treatment is started. Hand-held monitors and tiny needle stick devices can, almost painlessly, extract a small drop of blood for automatic testing in seconds. Insulin can be administered by the usual injections or via a wearable computer programmed pump. The big worry in insulin treatment is that an “overdose” can cause distress and even coma. Diabetic patients learn to recognize the signs of hypoglycemia (low blood glucose) and its rapid correction before losing consciousness.

Due to the size limit of this article, not discussed is the exciting and growing story of basic scientists, especially molecular biologists, who are pinpointing the exact reason that a high glucose level is harmful, as well as exactly why the insulin release and action system does not function in type 2 diabetes. It is fair to predict that within the next decade, the mysteries of diabetes will be largely solved. This success will reduce the number of diabetic people who go on to develop ESRD while improving the life quality of those diabetic people under treatment by dialysis and kidney transplantation. Although I worry over the growing toll of people captured by the pandemic of diabetes, I am optimistic in believing we are ever closer to a solution.

Eli A. Friedman, MD, is a Distinguished Teaching Professor of Medicine Chief, Renal Disease Division, at the Downstate Medical Center in Brooklyn, New York. Dr. Friedman is also the Chairman of AAKP’s Medical Advisory Board.

This article originally appeared in the December 2003 issue of Kidney Beginnings: The Magazine, Vol. 2, No. 4.

Back