by Barbara Berkeley, MD
In the late 1980s when I first started taking care of very overweight people, our clinic would occasionally treat a diabetic. Since we were using a full liquid diet at the time, we would put these people in the hospital and monitor them for as much as a week while adjusting their calories. This was before the days of hand-held glucose monitors that came in rainbow colors, before ads for diabetic testing supplies started running during soap operas, and before obesity had become a national epidemic.
I can't say exactly when the tide turned. But over the past ten years, diabetes has become the rule in my practice rather than the exception. Part of this comes from the fact that, in 2003, the American Diabetes Association lowered the threshold for the diagnosis of diabetes from a fasting blood sugar of 140 to one of 126. Naturally this "created" a lot more diabetics right away. At the same time as were were lowering the cut off for diabetes, we began to talk about "pre-diabetes", a condition that existed in those who had a morning sugar between 100 and 125.
For years, I have chafed against the pre-diabetes diagnosis. Why? Because all elevated blood sugars indicate a problem with the insulin system. Diabetes is a continuum, and when we use the term "pre-diabetes" we are not adequately warning the patient of the danger they face.
When people have anginal chest pain, we say that they have coronary artery disease. We call it the same thing after they have a full blown heart attack. We don't say that anginal patients are"pre-heart attack". Why not? Both conditions are part of the same continuum, one indicating partial blockage and the other complete blockage. A matter of degree.
Current ADA guidelines say that those with fasting blood sugars (measured after 8 hours without food) of 100-125 are "pre-diabetic". These same folks magically become diabetic when their sugars uptick by one unit and they test out at 126. That's like saying that you suddenly got coronary artery disease on the day your vessel clogged up completely.
The diagnosis of pre-diabetes doesn't scare people. They most often feel that they just have a mild warning and should check on the situation now and then. Bad thinking, encouraged by a poor choice of words. When your blood sugar exceeds 100 fasting, there IS a problem, an active one. More importantly, it is very likely that intervening early on in the course of diabetes works best and can prevent it from going further.
Yesterday, I attended a day-long course at the Cleveland Clinic on controversies in diabetes management. You won't be surprised to hear that my favorite lecture took the form of a debate between two endocrinologists who argued the following proposition pro and con: Should we change the diagnosis of diabetes to a fasting sugar of 100?
The con argument ran heavy on two points: first, that all the new diabetics created would demand medicines and that the cost of these medicines would be overwhelming. (There is also not compelling evidence that using medicines is the best way to go in the early stages). Second, that insurance companies wouldn't pay for treatment. Too many people would be diabetic and this would overwhelm the system. For me, this is an argument that protects the financial interests of insurance companies more than the interests of those whose pancreatic beta cells are failing. And besides, the early treatment of diabetes should really revolve around weight loss and diet change, something which can better be handled by large scale public health initiatives and education than by doctors.
Here are the pros. There is no reason why a healthy person should wake up with an elevated blood sugar. After all, that person hasn't eaten a thing for at least 8 hours. Elevated morning sugars indicate the presence of insulin resistance in the liver. Normally, the liver produces small amounts of sugar when you are not eating. In insulin resistant people, an inappropriately large amount is made resulting in a morning sugar which is high. Therefore, by definition, those with fasting sugars of over 100 have insulin resistance.
This in itself would not be so bad except for the following: We know that a blood sugar of 100 means that there is also early dysfunction of the pancreatic beta cells that make insulin. By the time a diagnosis of diabetes is made at today's level of 126, the average patient has experienced the death of 50% of these crucial cells. If we made the diagnosis at a FBS of 100, we might still have the opportunity to rescue these cells.
The current cut off of 126 was set because it is at this level that destruction of arteries in the retina begins to take off. However, data from the Diabetes Prevention Program Outcome Study shows that 8% of pre-diabetics already have retinal disease. Retinal disease, because it is easy to see, is just a marker for the fact that arteries throughout the body are beginning to be destroyed. Should we be waiting until a blood sugar of 126 before alerting people to the fact that they have a serious problem brewing?
It's also important to note that multiple studies show that for every 1 point your blood sugar increases above somewhere in the 75 to 80 range, your cardiovascular risk increases by about 1%. This observation was borne out by data from the huge Nurse's Health Study, which showed that women with no diabetes had a relative risk of developing heart attack and stroke of 1. Those women who were going to go on to become diabetic had a risk of nearly three times as high before the diagnosis of diabetes was ever made. Their risk had increased throughout the pre-diabetic range.
An elevated fasting sugar may indicate an even more worrisome problem and one that is usually not evaluated when someone is labeled "pre-diabetic". That problem is a burst of elevated blood sugar after meals. Multiple large trials including the large DECODE and Whitehall, Paris, Helsinki Studies have shown that high blood sugars two hours after a meal greatly increase mortality and risk from heart disease. Some studies have shown a doubling of risk. Yet most people who are told they have prediabetes or "borderline" blood sugar do not have the rest of their risk profile investigated.
Researchers have also clearly shown that the risks posed by diabetes are a continuum. They do not begin at a specific, initiating number. Wouldn't we want to know if we had just stepped onto a dangerous road and were still at a place where lesser interventions could still be successful?
Is it alarmist or even fair to vastly lower the cut off for diabetes? Walter Willet of the Harvard School of Public Health described a similar dilemma faced by experts charged with setting America's guidelines for obesity. Despite the fact that cardiovascular and diabetic risk began relatively low BMI, the panel of which he was part declined to lower the cut off for obesity. It was unthinkable to bring the number down and thus shove most of America into the obese category. But who was served by making this call? And who do we serve when we pretend that prediabetes is not a part of the same deadly disease that now "starts" at 126?
A huge number of overweight people have elevated fasting blood sugar. If you are one of them, it is my suggestion that you act as if you had been given the diagnosis of diabetes. Have a glucose tolerance test to evaluate post-meal sugars. Have a hemoglobin A1C to accurately check your average sugars over the past 3 months. Remove most starches and sugars from your diet to give you pancreas a rest from the job of churning out insulin against a resistant system. That, along with caloric restriction, will lead to weight loss which in turn will decrease the resistance problem. Exercise to sensitize muscles to insulin signaling and make them less resistant as well. And commit to an ancient diet, low in saturated fats, high in good fats and very low in insulin stimulating foods. We can take control of diabetes in this country, but first we must squarely face the fact that it is out there, all around us, from the moment our blood sugars start to climb.
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