Regression analysis for testing association between fasting blood sugar and glycated hemoglobin in diabetic patients

The cut-off criterion of serum levels of glycated hemoglobin (HbA1c) >6.5% as an alternative to fasting blood sugar (FBS) >7.0 mmol/L for diagnosis of diabetes mellitus still requires rigorous studies on diverse populations before its safe implementation. We conducted a regression analysis on 75 diabetic patients (40 males and 35 females) for testing the association between FBS and HbA1c and postulation of regression equations for inter-conversion of their levels. The average ± standard deviation values of FBS and HbA1c were 8.101 ± 3.917 mmol/l and 7.989 ± 2.112 %, respectively. Patients with HbA1c >6.5% had significantly higher levels of FBS. We observed a significant correlation between FBS and HbA1c (R= 0.717, P<0.001). The regression equations, HbA1c = 0.387 (FBS) + 4.855 and FBS = 1.33 (HbA1c) – 2.528, could be utilized for inter-conversions between the levels of FBS and HbA1c for predicting their expected values in diabetic patients. Further studies are warranted to examine the deviations from the regression equations in diabetic patients from different ethnicity and demography.