title: Does glucose variability influence the relationship between mean plasma glucose and HbA1c levels in type 1 and type 2 diabetic patients?
abstract: OBJECTIVE
  The A1C-Derived Average Glucose (ADAG) study demonstrated a linear relationship between HbA(1c) and mean plasma glucose (MPG). As glucose variability (GV) may contribute to glycation, we examined the association of several glucose variability indices and the MPG-HbA(1c) relationship.
  
  
  METHODS
  Analyses included 268 patients with type 1 diabetes and 159 with type 2 diabetes. MPG during 3 months was calculated from 7-point self-monitored plasma glucose and continuous glucose monitoring. We calculated three different measures of GV and used a multiple-step regression model to determine the contribution of the respective GV measures to the MPG-HbA(1c) relationship.
  
  
  RESULTS
  GV, as reflected by SD and continuous overlapping net glycemic action, had a significant effect on the MPG-HbA(1c) relationship in type 1 diabetic patients so that high GV led to a higher HbA(1c) level for the same MPG. In type 1 diabetes, the impact of confounding and effect modification of a low versus high SD at an MPG level of 160 mg/dL on the HbA(1c) level is 7.02 vs. 7.43 and 6.96 vs. 7.41. All GV measures showed the same tendency.
  
  
  CONCLUSIONS
  In only type 1 diabetic patients, GV shows a significant interaction with MPG in the association with HbA(1c). This effect is more pronounced at higher HbA(1c) levels. However, the impact of GV on the HbA(1c) level in type 1 diabetes is modest, particularly when HbA(1c) is close to the treatment target of 7%.
authors.affiliation: VU University Medical Center, Amsterdam, the Netherlands. jc.kuenen@me.com
authors.forename: Judith C
authors.initials: JC
authors.lastname: Kuenen
authors.forename: Rikke
authors.initials: R
authors.lastname: Borg
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Kuik
authors.forename: Hui
authors.initials: H
authors.lastname: Zheng
authors.forename: David
authors.initials: D
authors.lastname: Schoenfeld
authors.forename: Michaela
authors.initials: M
authors.lastname: Diamant
authors.forename: David M
authors.initials: DM
authors.lastname: Nathan
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Heine
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000378:metabolism*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin