The usefulness of the estimated average glucose/fasting blood glucose ratio for pancreatic β‐cell function assessment in hyperglycemia during health checkups

BACKGROUND: Type 2 diabetes (T2DM) is a disease marked by inadequate insulin secretion by pancreatic beta‐cell function (BCF) failure and insulin resistance (IR). Assessing and managing the BCF and IR should be started early to prevent or delay the progression of the disease. The aim of this study was to determine the usefulness of the estimated average glucose (eAG)/fasting blood glucose (FBG) ratio for pancreatic BCF in hyperglycemia. METHODS: This cross‐sectional study consecutively selected 10,594 subjects who underwent a health checkup at 16 health checkup centers in 13 Korean cities between 2019 and 2021. The subjects consisted of 3003 patients with normoglycemia, 3413 with impaired fasting glucose and 4178 with T2DM. The eAG was calculated using Nathan's regression equation. BCF and IR were estimated by the homeostasis model assessment (HOMA)‐β and HOMA‐IR, respectively. Multivariate (adjusted) regression analysis was performed to evaluate the association between the eAG/FBG ratio and HOMA. RESULTS: The median values among FBG groups for the eAG/FBG ratio, HOMA‐β, ‐IR and insulin differed significantly (p < 0.001). The second‐, third‐ and fourth‐quartile groups of the eAG/FBG ratio had positive higher correlation coefficients [9.533, 10.080 and 12.021, respectively (all p < 0.001)] for HOMA‐β than the first quartile group, and higher negative coefficients for HOMA‐IR [−0.696, −0.727 and −0.598, respectively (all p = 0.001)]. CONCLUSION: The eAG/FBG ratio was significantly correlated with both HOMA‐β and ‐IR, which suggests that eAG/FBG ratio reveals BCF and IR in hyperglycemia. Measurement of this ratio could be useful for monitoring BCF and IR in prediabetes and T2DM.