Dear Dr. Roach: I鈥檓 85 years old and a Type 2 diabetic. My fasting blood sugars are usually below 5.5. My physicians seem to worry about low blood sugars, and I am more concerned about slightly elevated blood sugars causing damage to my cardiovascular system and my kidneys. I鈥檝e had three close relatives die from complications from diabetes, and I know they were not able to control their blood sugars. Is it true that death due to low blood sugars is very rare? Is there evidence that there is an increase in strokes and cardiovascular events with every elevation of the A1c above five. Was the ACCORD trial that recommended an A1c of seven performed on a group of patients who were in the hospital and not in great health? Since all medications have some side effects, do you know if the multiple use of medications were the cause of the excessive numbers of deaths in the tight control group of patients?
C.R.H.
I would like to congratulate you on your desire to take the best care of your diabetes, but let me correct a few of your misapprehensions. Most important, death from hypoglycemia is unfortunately not rare. While it is more frequent in Type 1 diabetes (where it accounts for about six per cent of deaths), it is also frequent in Type 2.
When considering complications from diabetes, we separate them into microvascular complications 鈥� of the small vessels, especially in the kidneys, nerves and eyes 鈥� and macrovascular disease 鈥� of the large blood vessels to the heart and brain, and the great vessels of the body, like the aorta and femoral arteries.
It is microvascular disease in which A1c levels above five showed an increase, but most of the increase occurs over an A1c of seven per cent. For people with diabetic disease of the eye (retinopathy) and kidney (nephropathy), keeping the A1c as low as possible keeps the disease from advancing (although in the first year of changing to excellent control, the retinopathy paradoxically gets worse).
On the other hand, the ACCORD trial (involving generally healthy people age 40-79 with Type 2 diabetes, not hospitalized people) showed more deaths from macrovascular disease in the group with an A1c goal of less than six per cent, compared with the group with an A1c goal of 7-7.9 per cent. The difference was large enough that the study was halted and all participants were switched to a goal of about seven per cent. While it is possible that the increased use of diabetes medications was responsible for the deaths, most experts feel that the goal of lower than six per cent is too risky from the standpoint of macrovascular disease. The risk/benefit ratio for lower A1c is even less for older adults like you.
Every person with diabetes needs an individualized plan made by his or her doctor, who must negotiate the risks of microvascular disease from too high blood sugars with hypoglycemia and increased macrovascular disease from too low blood sugar. For most older Type 2 diabetics, the optimum level seems to be an A1c near seven.
