Association of HbA1c and Fructosamine with insulin resistance indices in gestational diabetes

Objectives: The levels of HbA1c and Fructosamine (FRA) in pregnant women with GDM (gestational diabetes mellitus) compared to non-GDM ones have been evaluated, then the association between the above two compounds with insulin resistance indices has been investigated.

Methods: Between September 2018 and March 2019, this study was performed on 400 pregnant women (50 with GDM and 350 without diabetes) referred to Kashmar Health Center Laboratory. Glycemic markers and insulin resistance indices were compared between women with GDM compared to Non-GDM ones by Mann-Whitney U and Independent sample t-tests. Linear regression test was used to investigate the relationship between insulin resistance indices with HbA1c and FRA in the two above groups. Results: Significant differences were observed in the levels of HbA1c (P <0.001) and FRA (P <0.001) between women with GDM and Non-GDM group. Results of linear regression considering age and group effects resulted in no significant correlations between HbA1c and IR indices (QUICKI (β= -1.98, P =0.22), HOMA-IR (β = 0.03, P=0.39), HOMA-B (β = 0.00005, P=0.41), 1/Insulin (β = -0.85, P=0.32), G/I (β = -0.005, P=0.62)). Likewise, no significant correlations between FRA and IR indices observed (QUICKI (β= 9.79, P =0.64), HOMA-IR (β = 0.07, P=0.88), HOMA-B (β = 0, P=0.67), 1/Insulin (β = -2.52, P=0.82), G/I (β = 0.02, P=0.86)). Conclusion: HbA1c and FRA were not directly affected by insulin resistance, and it can be concluded that any increase in insulin resistance may not be an exclusive factor for the elevation of HbA1c and FRA levels.