Influencia de la glucemia venosa en ayunas en el cálculo de la glucemia media estimada

Introduction

The estimated average glucose (eAG) level is an approximate calculation in mg/dL of the plasma concentration of glucose over the previous 60-90 days.

Objective

To determine the role of venous blood glucose during fasting and post-prandial levels in the calculation of eAG.

Material and methods

We included 413 patients with diabetes mellitus that were being treated between January and July 2012. We considered any condition that could modify the values of A1c as exclusion criteria. We measured the fasting venous blood glucose levels and A1c in the same samples. We calculated the eAG level of each A1c measurement, and the difference between each venous blood glucose level and the eAG of 909 pairs of values.

Results

The mean age of the patients was 64 ± 13.5 years old. From our sample, 53% were male, and 95% of these cases were suffering from type 2 diabetes. The average A1c in the sample was 8.1% ± 1.6%. The eAG level for this percentage was 186 mg/dL. The fasting venous blood glucose was 172 ± 69 mg/dL. The difference between the eAG and the average of the fasting venous glucose levels was 14 mg/dL. This was found to be significant with P < .01.

Conclusion

The eAG level is significantly higher than the mean of the levels in fasting in patients with diabetes. We can assume that this difference is due to the influence of the post-prandial glucose levels in the calculation of eAG; and that the contribution of fasting blood glucose to this calculation is approximately 92%, and that of post-prandial blood glucose only 8%.