Glucose Variability and Complications
- Geremia B. Bolli, MD
- From the Section of Internal Medicine, Endocrinology and Metabolism, Department of Internal Medicine, University of Perugia, Perugia, Italy
- Address correspondence to Geremia B. Bolli, MD, University of Perugia, Department of Internal Medicine, Section of Internal Medicine, Endocrinology and Metabolism, Via E. Dal Pozzo, I-06126 Perugia, Italy. E-mail: bolli{at}unipg.it
In this issue of the Diabetes Care, Kilpatrick et al. (1) report their analysis of the large Diabetes Control and Complications Trial (DCCT) database on the relationship between glucose variability and relative risk of developing microangiopathic complications in type 1 diabetes. They find that glucose variability (intraday blood glucose excursions) does not play a role and conclude that only elevation of mean blood glucose over time (as expressed by its integrated measure over the previous ∼8 weeks’ A1C) associates with proportionally greater risk of developing microangiopathy long term.
This result translates into an important, practical message for subjects with type 1 diabetes and people delivering diabetes care (doctors, nurses, educators, dietitians, etc.). Consider the following example: two young subjects with newly diagnosed type 1 diabetes initiate intensive insulin treatment and are both able to maintain similar A1C <7.0% over the years. However, one subject exibits minor intraday excursions in blood glucose, whereas the other has large peaks of hyperglycemia, for example after meals, but still maintains A1C <7.0% by compensatory prolonged plateaus of low blood glucose between meals. According to the results of Kilpatrick et al., the latter subject with elevated variability in intraday blood glucose, but A1C <7.0%, has no additional risk of developing microangiopathic complications compared with the former subject with greater stability of blood glucose and similar A1C. This conclusion indicated by the study of Kilpatrick et al. deserves some comments.
First, the conclusion is unexpected. The current, prevalent hypothesis based on in vitro data is that glucose variability might play an important role in the risk for long-term microangiopathic complications of type 1 diabetes (2). According to this view (2), intraday glucose variability would explain the epidemiological observation of the DCCT of greater risk for retinopathy progression in the conventional compared with intensive treatment when …
