Diabetes, Glucose Control & Death

May 24, 2009

By, Robert A. Wascher, MD, FACS

Updated: 05/24/2009

The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.

DIABETES, GLUCOSE CONTROL & DEATH

According to the Centers for Disease Control (CDC), nearly 25 million Americans, or 8 percent of the population, have diabetes; and the incidence of this obesity-linked disease continues to rise along with our collectively expanding waistlines. In addition to being an enormous public health problem, diabetes is a major contributor to our country’s budget-busting healthcare costs, as an estimated $175 billion is spent every year in the United States in treating diabetes and diabetes-associated complications.

Not only is diabetes becoming a more commonly diagnosed affliction every year, but an estimated 57 million additional non-diabetic Americans also have a condition known as prediabetes. Patients with prediabetes already have elevated blood sugar (glucose) levels, although their hyperglycemia has not yet reached the level necessary for the diagnosis of diabetes. Therefore, we appear to be on the precipice of a true epidemic of diabetes in the United States, as well as in many other countries around the world, as prediabetes is a huge risk factor for subsequently developing diabetes.

Type 2 diabetes, which used to be a disease that almost exclusively afflicted older adults, is now increasingly common among young adults, adolescents, and children, as the incidence of obesity in these age groups continues to rise. Although diabetes affects people from all ethnic backgrounds, it is especially prevalent among certain ethnic groups, including Latino Americans, African Americans, Pacific Islanders, Native Americans and Asian Americans. In addition to obesity and ethnicity, other known risk factors for Type 2 diabetes include living a sedentary lifestyle, having a family history of diabetes, having diabetes during pregnancy (gestational diabetes), and advancing age.

In its early stages, diabetes generally causes no symptoms and, indeed, some experts have estimated that as many as one-fourth of all people with diabetes do not even know that they have the disease. Unfortunately, even relatively advanced cases of diabetes can be missed by patients, or their physicians, as the symptoms of diabetes can be rather subtle and non-specific. (Symptoms that are commonly associated with the onset of diabetes include frequent urination, increased thirst, increased hunger, weight loss, and increased fatigue.)

Diabetes deserves its nickname, “The Silent Killer,” because its insidious effects on the body’s vital organs can lead to a variety of disabling and life-threatening complications. These include dental disease, peripheral nerve damage, accelerated cardiovascular disease, blindness, kidney failure, and premature death. Accelerated atherosclerosis in diabetics can lead to heart attacks, heart failure, stroke, impotence in men, and the loss of limbs. Cumulative damage to the retinas can result in progressive vision loss and blindness. Ongoing injury to the kidneys can result in the complete loss of kidney function, requiring dialysis or, if available, kidney transplantation. As the peripheral nerves are slowly destroyed by diabetes, patients often develop an unpleasant “pins and needles” sensation of their legs and feet (and, sometime, of their hands and fingers as well), and these paresthesias can ultimately progress to complete numbness of the affected extremities. These types of “end organ” damage often occur insidiously and painlessly in patients who have chronically uncontrolled diabetes. What’s more, once the body’s vital organs become damaged by chronic diabetes, this damage is usually permanent. Unfortunately, many patients only learn that they have diabetes when one or more of these serious diabetes-associated complications have already occurred.

Although diabetes is currently listed as the seventh most common cause of death in the United States, most public health experts believe that this is a gross underestimate, as death records very often do not contain adequate clinical information to directly link diabetes as a contributing cause of death. (Having diabetes essentially doubles one’s risk of dying prematurely, when compared to healthy same-aged people without diabetes.)

The best treatment for diabetes, as with many other diseases, is prevention. Eating a healthy and balanced diet, and avoiding over-eating, is a critically important approach to preventing diabetes. Maintaining a weight that is appropriate for your height, and getting plenty of regular exercise, will also significantly help to lower your risk of developing diabetes. Once a patient is diagnosed with diabetes, an aggressive approach to treatment is necessary in order to minimize the risk of this disease’s devastating potential complications. Carefully controlling blood glucose levels, as well as treating the high blood pressure and elevated cholesterol levels that typically accompany diabetes, are the foundations of modern diabetes management.

Despite the billions of dollars that have, so far, been invested in diabetes research, there remains a great deal of debate among diabetes experts as to how tightly patients must control their blood sugar levels in order to maximally reduce the potential complications of diabetes (including death). The data from previously published clinical research studies have actually been somewhat contradictory in this regard, and some of these studies have suggested that excessively stringent blood sugar control can actually increase the risk of complications (including death), presumably due to episodes of very low blood sugar (hypoglycemia).

A new study, just published in the prestigious journal The Lancet, uses a process known as meta-analysis to evaluate five of the largest published prospective randomized diabetes clinical research studies, encompassing a total of 33,040 patients. A meta-analysis is a complex statistical process that helps to equalize the variable research conditions that exist between different (but similar) clinical research trials, in an effort to accurately combine the findings of multiple research studies, and to increase the statistical power and accuracy of these studies. Meta-analysis is often used to combine the results of different and rather small research studies, such that one can draw conclusions as if all of the study patients were originally included in a single, large, and uniform clinical research study. (It should be noted that meta-analyses are not considered to be as statistically powerful, and as free from potential bias, as are very large prospective randomized clinical research studies.)

Among the more than 33,000 diabetic patients included in the five original clinical trials, there were 1,497 new cases of non-fatal heart attacks (myocardial infarction), 2,318 newly diagnosed cases of coronary artery disease, 1,127 new strokes, and 2,892 deaths (from all causes).

Patients that were in the “intensive glucose control” groups within these five studies were found to have experienced 17 percent fewer non-fatal heart attacks when compared to the patients who were randomized to the “standard glucose control” groups. Similarly, the diabetic patients in the intensive glucose controls groups were 15 percent less likely to be diagnosed with coronary artery disease during the course of these five studies, when compared to the patients who received standard management of their diabetes. At the same time, intensive glucose control neither increased nor decreased the overall death rate observed during the course of these five studies. Additionally, the risk of stroke did not appear to be altered by more intensive blood glucose management in these five prospective randomized clinical research trials.

In view of the results of these five clinical trials, and of this exhaustive meta-analysis, we can definitely conclude that the very tight control of blood sugar levels in diabetic patients appears to reduce the risk of coronary artery disease and non-fatal heart attacks, and that stringent blood glucose control does not appear to increase the risk of fatal complications (at least among diabetic patients who are being closely monitored by their diabetes physicians). At the same time, the fact that there was no observed reduction in the risk of death with very tight glucose control is, of course, disappointing. However, it may be the case that tightly controlling blood sugar levels will eventually be shown to save lives (due, primarily, to a reduction in the risk of coronary artery disease), but that longer periods of observation will be necessary to reveal this potential benefit of a more stringent approach to blood glucose control.

Based upon the results these (and other) diabetes research studies, if you have diabetes, you should work closely with your physician to improve the control of your blood sugar levels through a combination of diet, exercise, weight reduction and, if necessary, medication. All available research evidence suggests that these approaches will offer you the best possible protection against the life- and limb-threatening complications associated with diabetes.

Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity

Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and a Surgical Oncologist at the Kaiser Permanente healthcare system in Orange County, California

(Anticipated Publication Date: March 2010)

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Robert A. Wascher, MD, FACS

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