by Wesley W. Wilson, MD
Includes Art: Medical Caduceus
NOTE: If you have any questions for "Ask the Doctor," please send them to the Voice editorial office. The only questions Dr. Wilson will be able to answer are the ones used in this column.
Wesley W. Wilson, MD has retired as an Internal Medicine practitioner at the Western Montana Clinic in Missoula, Montana. Dr. Wilson was diagnosed with type 1 diabetes in 1956, during his second year of medical school. He remains interested and involved in diabetes education for patients and professionals.
Question: What is the “ideal” A1C for a diabetic?
I always heard my numbers should be no higher than 7 percent, but now my doctor
is saying that it should be 6.5 percent or lower. What’s right?
Answer: Your question is important, and it needs a good answer. These days,
when we have the ability to measure “glycosylated hemoglobin” (Hemoglobin
A1C) at home, or get the values from our health care provider, we need to know
what we should be trying to achieve. My first answer is: It depends. Perhaps
some background information will help.
The Diabetes Control and Complications study (DCCT) was a multi-year trial in which the questions asked included: 1) Can careful control of blood sugar in persons with type 1 diabetes reduce the appearance and/or the progression of complications? and 2) Is extremely “tight” control of blood sugar possible without devastating problems from hypoglycemia (low blood sugar)?
The DCCT was set up to compare two groups of persons with type
1 diabetes. One group was treated “conventionally,” with self blood
sugar testing one or two times a day, occasional contact with the treating team,
and avoidance of excessively high or low sugars. By comparison, the intensively
treated group, who sought to achieve near normal blood sugars, checked sugars
three or more times each day, saw the treating team about every two weeks, and
took insulin three or four times daily, or used insulin pumps. They were truly
treated intensively. The “target” A1C, the point they sought to
reach and hold, was a “normal” A1C, that is 6 percent or less. Despite
efforts to carefully control blood sugar in the intensely treated group, only
5 percent of the group were able to achieve such a “normal” HbA1C,
and the average A1C was 7 percent, one percent higher than planned. Hypoglycemia
limited the ability to control blood sugar. In contrast, the conventionally
treated group had A1Cs averaging 9 percent.
Even though there was less than perfect control in the intensively treated group
and the A1C was reduced by only 2 percent, the rate of complications was reduced
by more than 50 percent after 6 years. The 2 percent reduction in A1C clearly
reduced complications. Unfortunately, the intensively treated group had twice
as many episodes of severe hypoglycemia, which required help by some other person
to revive the affected individual. The price for extremely tight control is
certainly a greater risk of severely low blood sugar.
The question remained: how low was it possible to safely get the A1C in ordinary
persons with diabetes? The American Diabetes Association decided that the 7
percent average result achieved in the DCCT should be the target, since it had
been achieved in over 700 people, and it did reduce complications.
Of course, we all wonder if a “normal” A1C might not reduce complications
even more. Some persons are able to attain normal A1C, and if they can, I’d
say go for it! But, be aware that there are greater risks from hypoglycemia.
Accidents in diabetics must always raise the question of low blood sugar.
I should mention that similar results are seen in type 2 diabetes. The United
Kingdom Prospective Diabetes Study demonstrated similar protection in persons
with type 2 disease. The intensely treated group in that study had an A1C that
was about 2 percent lower than the less intensely treated one.
I try to have my A1C as low as possible, but if I’m involved in lots of
physically active sports, I must run blood sugars a little high to avoid the
need to take sugar all the time. There is no one “right” A1C; it
truly does DEPEND.
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If you or a friend would like to remember the Diabetes Action Network of the National Federation of the Blind in your will, you can do so by employing the following language:
"I give, devise, and bequeath unto the Diabetics Action Network of the National Federation of the Blind, 1800 Johnson Street, Baltimore, Maryland 21230, a District of Columbia nonprofit corporation, the sum of $_______________" (or "_______________ percent of my net estate" or "the following stocks and bonds:____________________") to be used for its worthy purposes on behalf of blind persons."
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