January 5, 2011
Hypoglycemia, Research: Other Research
Question from Ada, Michigan, USA:
My son is nearly six years old and has had type 1 diabetes for four years. He has been using an insulin pump for almost two years. My wife and I are quite diligent in checking his blood glucose: usually 10 or more times daily, including a 2 a.m. check. We aim for a balance between tight control and avoiding lows, while at the same time trying to give him as "normal" an existence as possible in regards to eating and activities. His A1c is generally in the 6% range (most recent value was an all-time low of 5.9%). My son experiences hypoglycemia (blood sugar value < 60 mg/dl [3.3 mmol/L]) perhaps three or four times per week, generally in the 50s mg/d [2.8 to 3.2 mmol/L] but occasionally in the 40s mg/dl [2.3 to 2.7 mmol/L]. Sometimes he is aware and informs us, other times he is asymptomatic. We have found that his awareness has improved a bit as he ages and he becomes more cognizant of the feeling of being "low." He has never experienced an overtly bad outcome such as seizure or unconsciousness. His physician, a pediatric endocrinologist, generally applauds our tight control and diligence. He has stated that we probably have as few episodes of hypoglycemia as can be expected with such tight control, but the most recent A1c gave him some pause. My question is specifically in regards to hypoglycemic episodes. I understand that these are to be avoided, and that the "party line" from the professional societies is that, at his age we, should aim for higher A1c values and therefore lower risk of hypoglycemia. However, we are concerned about the fact that he will be struggling with diabetes for many decades, nearly his entire life, pending a cure, and, therefore, is at risk for complications. We would like to avoid these painful and life-shortening complications, if at all possible. Aside from the obvious risks of hypoglycemia (seizures, etc.), are these low values--which are unavoidable, to some extent--intrinsically harmful? Is there good evidence that it can lead to long-term sequelae, such as cognitive or memory problems? Balancing these issues is something with which we struggle daily.
It sounds like you are all doing a terrific job. You are correct; the balance is always between safety issues, such as excessive or severe hypoglycemia, and overall glucose control/A1c levels. The more monitoring and the more proactive are your responses, the better your results will be. The long term issues with hypoglycemia relate to severity and you are not having convulsions or unconscious reactions. Those are the risks of tight control. Obvious immediate risks occur when hypoglycemia occurs and one is taking a test, reading, using machinery and making decisions. Frequent monitoring usually allows these to be recognized and treated.
There is an excellent study by one of our colleagues, Professor Eugen Schoenle, at the Children’s Hospital in Zurich. We all assumed that most long term brain type problems would reflect the degree and intensity of hypoglycemia in those with diabetes. He and his study team looked at this prospectively in a very elegant scientific study and found just the opposite. Chronic hyperglycemia/high A1c predicted much worse intellectual and brain functioning than did hypoglycemia.
My general advice would be to keep doing the excellent job you are doing and keep being vigilant to try to identify proactively ways to minimize hypoglycemia at the same time.