Assessment of agreement between estimated average glucose and single-point fasting plasma glucose with varying glycemic control

A bstract Background: The use of estimated average glucose (eAG) derived from glycated hemoglobin (HbA1c) has gained popularity in clinical settings. However, with usage, concerns emerged regarding reported discrepancies in the strength of correlation between eAG and fasting plasma glucose (FPG) among patients with varying glycemic control. Objective: To determine the correlation between eAG and FPG among Nigerian diabetic patients with varying glycemic control. Materials and Methods: This was a cross-sectional hospital-based empirical study carried out at the University of Nigeria Teaching Hospital, Enugu. Participants with adult type 2 diabetes mellitus were recruited from the Endocrinology Clinic. eAG was derived from HbA1c values, whereas FPG was analyzed using the glucose-oxidase method. A P value of < 0.05 was considered statistically significant. Results: Of the 148 participants, 53(35.8%) had good glycemic control, whereas 95(64.2%) had poor glycemic control using FPG. The correlation between eAG and FPG was weak and not significant among (r =0.0775, P = 0.5812) well-controlled participants but positive, moderate, and significant (r = 0.5849, P < 0.00001) among poorly controlled participants. The eAG/FPG ratio significantly increased with FPG decrease. Conclusion: Our study findings suggest that the strength of the correlation between eAG and FPG depends on the level of glycemic control in patients. Hence, concurrent reporting of eAG with HbA1c values ought to be done with consideration of the patients’ glycemic status. The eAG/FPG ratio may have relevance in determining insulin resistance in diabetic adult patients.