Can postprandial blood glucose excursion be predicted in type 2 diabetes?

Objective: We investigated the relationship between carbohydrate intake and postprandial blood glucose (BG) levels to determine the most influential meal for type 2 diabetic subjects treated with basal insulin and needing prandial insulin.

Research Design And Methods: Three-day BG profiles for 37 type 2 diabetic subjects, with A1C levels of 7.7%, treated with sulfonylurea and metformin, and well titrated on insulin glargine, were analyzed using a continuous glucose monitoring system. Food intake from 680 meals was recorded and quantified during continuous glucose monitoring.

Results: The median BG excursion (DeltaBG) was higher at breakfast than at lunch or dinner (111 [81; 160] vs. 69.5 [41.5; 106] and 82.5 mg/dl [53; 119] mg/dl, P < 0.0001). There was a weak overall correlation between DeltaBG and carbohydrate intake. Correlation improved when mealtime was taken into account. Simple relationships were established: DeltaBG (mg/dl) = 65 x carbohydrate/body weight + 73 for breakfast (R(2) = 0.20, P < 0.0001); the slope was reduced by half at lunch and by one-third at dinner. Twelve relevant variables likely to affect DeltaBG were integrated into a polynomial equation. This model accounted for 49% of DeltaBG variability. Two groups of patients were identified: responders, in whom DeltaBG was well correlated with carbohydrate intake (R(2) >or= 0.30, n = 8), and nonresponders (R(2) < 0.30, n = 29). Responders exhibited a greater insulinopenic profile than nonresponders.

Conclusions: The carbohydrate intake in responders clearly drives DeltaBG, whereas, in nonresponders, other factors predominate. This sort of characterization should be used to guide therapeutic choices toward more targeted care with improved type 2 diabetes management.