I recently read the article The relationship of A1c to glucose concentrations in children with type 1 diabetes: Assessments by high frequency glucose determinations by sensors. Does this mean that the A1c is not a strong indicator of true average blood glucose levels in type 1 diabetics? Is there any list of factors which would cause the A1c to vary more or less widely from true average blood glucose levels?

The A1c remains a critical measure in the care of people with diabetes and provides a good measure of an individual average blood control in most case. By measuring the average, however, the A1c gives no indication of how variable the glucose is, so frequent glucose measurements are essential, particularly for those with type 1 diabetes.

The two main points of this article are that

Across different individuals, the relationship between their average glucose, measured essentially 24 x 7 for three months using glucose sensors, can have different A1cs. In other words, people with the same “average” glucose might have differing A1cs. This is a hot topic now, as some are suggesting the A1c should be “converted” to a mean glucose concentration before the results are told to patients.

An individual’s tendency to have a higher or lower A1c (for the same average glucose) may well be consistent over time. In other words, some people may be faster or slower at sticking glucose onto proteins – this is a controversial issue right now, as is the question of whether or not this tendency (if is exists) has any relationship to the development of long term complications.

More information about glucose levels and A1c is coming as the use of glucose sensors becomes more routine.

DW