Linköping, Sweden

Author Affiliations: Division of Pediatrics and Diabetes Research Centre, Department of Molecular and Clinical Medicine (Samuelsson U, Ludvigsson J) and Division of Drug Research/Pharmacology, Department of Medical and Health Sciences (Whiss PA), Linköping University, Sweden; Department of Pediatrics, Uddevalla Hospital, Sweden (Hanas R)

Corresponding Author: Ulf Samuelsson, Division of Pediatrics, Department of Molecular and Clinical Medicine, University Hospital, SE-581 85 Linköping, Sweden (Tel: +4613222000; Fax: +4613148265; Email: ulf.samuelsson@lio.se)

Background: HbA_1c levels are influenced by the glycemic control of previous 2-3 months. Sometimes patients have surprisingly low HbA_1c in spite of many correctly measured high blood glucose values, which is difficult to explain. As glucose sensors give an objective picture based on glucose readings several times per minute over 24 hours, we used the area under the curve (AUC) of such subcutaneous glucose profiles to evaluate their relationship with HbA_1c.

Methods: Thirty-two patients were randomized into two study arms, one open and the other blinded. Both arms had 8 pump users and 8 patients with multiple daily injections (MDI). After three months the two arms crossed over. Both study arms wore a continuous glucose monitoring system (CGMS) for 3 days every 2 weeks. HbA_1c was determined before and after each 3-month study period.

Results: There was no relationship between HbA_1c and s.c. glucose AUC or between HbA_1c and the number of peaks >15.0 mmol/L when all CGMS profiles during the 6 months were taken together. Children on MDI showed a positive relationship between HbA_1c and AUC (P<0.01) as well as the number of peaks (P<0.01). Children with a negative relationship between HbA_1c and AUC generally had fewer fluctuations in blood glucose values, whereas children with a positive relationship had wide fluctuations.

Conclusions: Although there was no relationship between s.c. glucose AUC and HbA_1c, the results indicate that wide blood glucose fluctuations may be related to high HbA_1c values. Therefore, complications and therapeutic interventions should aim at reducing such fluctuations.

Key words: blood glucose; diabetes; HbA_1c; multiple daily injections

                                                                                                             World J Pediatr 2008;4(3):215-221