No Relevant Relationship between Glucose Variability and Oxidative Stress in Well-Regulated Type 2 Diabetes Patients

BACKGROUND: A strong relationship between glycemic variability and oxidative stress in poorly regulated type 2 diabetes (T2DM) on oral medication has been reported. However, this relationship was not seen in type 1 diabetes. The purpose of this study is to reexamine the relation between glycemic variability and oxidative stress in a cohort of T2DM patients on oral medication. METHODS: Twenty-four patients with T2DM on oral glucose lowering treatment underwent 48 hours of continuous glucose monitoring (CGMS® System GoldTM, Medtronic MiniMed) and simultaneous collection of two consecutive 24-hour urine samples for determination of 15(S)-8-iso-prostaglandin F2α (PGF2α) using high-performance liquid chromatography tandem mass spectrometry. Standard deviation (SD) and mean amplitude of glycemic excursions (MAGE) were calculated as markers of glycemic variability. RESULTS: Included in the study were 66.7% males with a mean age (range) of 59 (36-76) years and a mean (SD) HbA1c of 6.9% (0.7). Median [interquartile range (IQR)] urinary 15(S)-8-iso-PGF2α excretion was 176.1 (113.6-235.8) pg/mg creatinine. Median (IQR) SD was 31 (23-40) mg/dl and MAGE 85 (56-106) mg/dl. Spearman correlation did not show a significant relation for SD (ρ = 0.15, p = .49) or MAGE (ρ = 0.23, p = .29) with 15(S)-8-iso-PGF2α excretion. Multivariate regression analysis adjusted for age, sex, HbA1c, and exercise did not alter this observation. CONCLUSIONS: We did not find a relevant relationship between glucose variability and 15(S)-8-iso-PGF2α excretions in T2DM patients well-regulated with oral medication that would support an interaction between hyperglycemia and glucose variability with respect to the formation of reactive oxygen species.