For patients with type 1 or type 2 diabetes, pre-prandial glucose levels are generally more closely associated with long-term HbA1c levels than post-prandial glucose levels, according to a new study.
"Our study shows that pre-prandial glucose values have a larger impact on HbA1c levels, presumably because they resemble the 24-hour, and thus the long-term, glucose levels more closely," Dr. Rikke Borg from the Steno Diabetes Center, Gentofte, Denmark, told the EASD conference.
In the (Hb)A1c Derived Average Glucose (ADAG) study, an analysis of 3 months of intensive glucose measurements demonstrated that the mean blood glucose derived from seven-point profiles predicts HbA1c with a precision of plus or minus 1.65% in both type 1 and type 2 diabetics.
From this intensive glucose monitoring data, the researchers determined which self-monitoring, meal-related blood glucose values of the day provide the best prediction of mean blood glucose, measured as HbA1c.
Blood glucose measurements were obtained pre- and post-meal for approximately 10 full days during the 3-month study for each of 273 type 1 diabetics and 168 type 2 diabetics in the study, yielding an average of 66 meal-related blood glucose measurements per subject.
"Self-monitoring blood glucose at particular times of the day were stronger predictors of HbA1c than others; and the relationship was different for type 1 diabetes and type 2 diabetes," Dr. Borg reported.
"In general, the combined pre-meal values predicted HbA1c better than combined post-meal values for both diabetes types, and particularly for type 2 diabetes," she noted.
For type 1 diabetes, pre-breakfast, pre-lunch, and post-lunch values predicted HbA1c the best, and for type 2 diabetes (both non-insulin- and insulin-treated), the pre-breakfast and post-lunch, and pre-dinner values provided the best prediction.
"These findings provide insight for the patient and clinician who seek the optimal blood glucose monitoring at minimal expense and discomfort," Dr. Borg and colleagues conclude in their meeting abstract.
Reported at the European Association for the Study of Diabetes annual conference in Rome, Sept 2008.
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