December 3, 2008
A1c (Glycohemoglobin, HgbA1c)
Question from St. Louis, Missouri, USA:
I have a question regarding A1c levels in children. I have an eight-year-old son with type 1 diabetes. We have adapted to diabetes management as a family and have some really great doctors helping us out. However, one item of extreme frustration to me is our inability to get my son’s A1c below 7.0. Despite several different methods, his A1c always seems to be over 8.0, usually between 8.0 and 8.75. We are now moving to an insulin pump, which holds the promise of tighter control.
I would like to have more data regarding the effects of elevated A1cs on children. As we have discussed more aggressive control techniques with our endocrinologist, we have received feedback that at earlier ages, it is better to avoid hypoglycemic incidents, which can cause immediate damage to a child, and strive for tighter control once the child is older (puberty). The implication is that elevated glucose levels, although undesired, typically do not cause complications in young children, and if tighter control is established prior to puberty, do not pose long term health risks. Is this a generally accepted opinion in the health care community?
You are correct. There is some controversy about this. The single biggest proponent of letting A1c levels stay higher (Pittsburgh researchers) to avoid hypoglycemic issues was proved wrong by multiple studies since then. The follow-up studies from Brussels, Sydney and Zurich did not find these same problems and they suggest that the pre pubertal years do count for long term complications and I would concur with those newer studies. However, all efforts to improve A1c always must be balanced by avoiding hypoglycemic convulsions, hypoglycemia unawareness or loss of consciousness and repeat episodes of hypoglycemia. If you want to look up the researchers at the NCBI, PubMed web site, the key authors of the various studies are Kim Donaghue, Harry Dorchy, and Eugen Schoenle.
Having your diabetes team set you up for a three day trial of CGMS would identify such problems as would more pre- and postprandial blood sugar testing plus overnight blood sugar testing. In your case, with A1c levels still hovering above 8% despite your efforts, I would wonder about postprandial hyperglycemia, timing of insulin to meals (i.e., should be 15 minutes ahead of food intake to catch the postprandial levels). Missed insulin doses and/or frequent overeating usually is more of a problem in adolescents and adults than in younger children but this also is a common cause. Using an insulin pump, especially with a CGMS, would be an ideal way to be more physiologic and you should be able to reach such tight A1c goals safely as do many of our own patients.