The Association between Glycated Hemoglobin and Estimated Glomerular Filtration Rate in Patients with Type 2 Diabetes based on the Hemoglobin Status

The aim of the present study was to examine the association between hemoglobin A1C (HbA1C( and eGFR in patients with type 2 diabetes (T2D).

This cross-sectional study was conducted on 802 patients with T2D visiting Abu Reyhan Clinic of Shahid Mohammadi Hospital in Bandar Abbas, Iran. eGFR was determined using MDRD and EPI methods. The association between two levels of HbA1C (≤8% and >8%) and two levels of GFR (≤60% and >60%) were assessed in total population, and separately, in men and women using linear regression model.

The mean ± SD age of the study population (27.7% male) was 53.5 ± 5.5 years. Based on the multivariable adjusted model, in subjects with HbA1C >8%, there was a negative association between HbA1C and eGFR-EPI (β = -0.14) and eGFR-MDRD (β = -0.12), (P<0.05). However, there was no significant relationship between HbA1C and eGFR in individuals with HbA1C ≤8%. Also, no significant association was found between HbA1C and eGFR as categorical variables (based on the two categories of eGFR ≤60 and >60). An inverse association was observed between GFR ≤60 and HbA1C >8% in women based on the Hb classification. This inverse association was found between HbA1C >8% and eGFR-EPI (β = -0.76) and eGFR-MDRD (β = -0.78) in women with Hb >12 mg/dl (P<0.01).

According to the results, the higher level of HbA1C can be associated with decreased eGFR level. This negative association was mostly observed between HbA1C >8% and GFR ≤60 in T2DM female patients without anemia (Hb>12). It seems that monitoring kidney function by eGFR estimation is a necessary action in patients with T2D with high HbA1C levels.