December 8, 2010
Complications, Research: Other Research
Question from Crosswicks, New Jersy, USA:
I know that the HgbA1c is the tool we have for monitoring long term control of blood sugars in diabetics. However, I have read/heard of research saying that fluctuations in blood sugar can be just as critical in preventing long term damage, especially with regards to the small vessels in the eye. I am hearing that blood sugar fluctuations from 200 to 70 mg/dl [11.1 to 3.9 mmol/L], then back up to 200 mg/dl [11.1 mmol/L] can be harmful if these types of fluctuations happen often enough. What does the latest research say about this? My son, who has had type 1 for almost five years, has never had a HgbA1c higher than 6.7 (and the 6.7 was an aberration since it normally is 5.8 to 6.0). However, he does have swings sometimes and my understanding is that it is very difficult to avoid these high to low and low to high fluctuations. In other words, diabetics have a difficult time maintaining a steady 80 to 125 mg/dl [4.5 to 6.9 mmol/L] glucose all the time, correct? How damaging are these wild swings in blood sugar and are these swings just as detrimental as having a high HgbA1c?
Answer:
What you are asking about is called MAGE: mean amplitude of glycemic excursions. It is a research construct discussed over the past few years and complements A1c measurements. A1c is validated through many studies, especially the DCCT, and acts as a surrogate “average” glucose as well as a surrogate for determining long term complications risk. Most of the time, when there are higher swings, there also are high A1c levels. Even our best pump treatment with CGMS is not as good, however, as a working pancreas so you are also correct in your assessment of frequent swings. More blood sugar monitoring, better insulin dose timing, better proactive adaptations for illness, activity, different foods, emotions and growth issues all contribute to improve glycemic control, lower A1c and lower MAGE – all goals for which we try to strive while at the same timing avoiding and preventing many of the extreme lows and highs. The A1cs you report are quite excellent so keep at it!
SB
