Reproducibility of a glycemic response to mixed meals in type 2 diabetes mellitus

To evaluate the inter-patient and intra-patient reproducibility of the glycemic response to a mixed meal in individuals with type 2 diabetes mellitus (DM).

Six individuals with DM were admitted to the General Clinical Research Center for 6 days.

Subjects consumed 3 different meal plans consisting of 4 meals daily (breakfast, lunch, dinner and snack) on 2 separate occasions. Serum insulin and glucose levels were sampled at 19 time points every day. The glycemic response (GR) to a meal was calculated as the area under the glucose response curve after consumption of a given meal. In addition, the incremental area under the curve (IGR) was calculated assuming a pre-prandial (baseline) glucose value before each meal as zero.

Intra-patient correlation coefficients (R) of GR for meals in subjects with DM were quite good, ranging 0.69-0.94. The range of the inter-patient coefficients of variation (CV) for the same meals was 21.5-30.4%. For IGR, the R values ranged from 0.64 to 0.91 for 8 out of 12 meals, confirming good intra-patient reproducibility for these meals. CV for IGR ranged from 31% to 113%.

For patients with DM, the GR of individual meals exhibits excellent intra-patient reproducibility, allowing prediction of the glycemic response to a given meal in an individual subject. However, significant inter-patient variability of the GR precludes its use for the prediction of post-prandial glucose concentrations in groups of patients with diabetes.