Kuenen, Judith C.Borg, RikkeKuik, Dirk J.Zheng, HuiSchoenfeld, DavidDiamant, MichaelaNathan, DavidHeine, Robert J.2013-03-262011Kuenen, Judith C., Rikke Borg, Dirk J. Kuik, Hui Zheng, David Schoenfeld, Michaela Diamant, David M. Nathan, and Robert J. Heine. 2011. Does glucose variability influence the relationship between mean plasma glucose and \(HbA_{1c}\) levels in type 1 and type 2 diabetic patients?. Diabetes Care 34(8): 1843-1847.0149-5992http://nrs.harvard.edu/urn-3:HUL.InstRepos:10464973Objective: 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. Research Design and 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%.en-USPathophysiology/ComplicationsJournal Article2013-03-2610.2337/dc10-2217