Correlation of Red Blood Cell Distribution Width (RDW) and Hemoglobin A1C (HbA1c) Levels, In Patients with Type 2 Diabetes Mellitus

Abstract

The incidence of Diabetes Mellitus is increasing worldwide, with almost 1/3 of adults being affected. It is the major contributor to the morbidity of a man with its multi-organ system complications. Control of blood glucose levels is vital to decrease organ damage and complications. Routine diagnostic tests conducted are blood glucose, lipid profile, renal function tests, HbA1c, and insulin assays with a baseline CBC (Complete Blood Count). HbA1c values continue to be the gold standard for the assessment of glycemic control. The RDW (Red Cell Distribution Width) is a parameter of Complete Blood Count. Several studies have shown elevated RDW values in patients with poor glycemic control and as an early marker for Diabetic nephropathy and cardiovascular complications. 610 patients with type 2 Diabetes Mellitus attending the Diabetic Clinic in Saveetha Medical College were included in a cross-sectional study to compare HbA1c values with RDW values with age and gender. The ratio of patients with poor HbA1c levels: acceptable HbA1c levels of glycemic control was1:4 in the age group 25 years and below. The ratio rose to 1:1 in the 36-45 years age group with a reversal of ratio to 4:1 in patients >65years of age. There was a significant correlation between the values of HbA1c with age - with the number of patients increasing with age and showing elevated HbA1c levels. There was no significant correlation between the values of RDW and age. There was a significant positive correlation between HbA1c and RDW- (p = 0.003, < 0.05 standard). For patients with HbA1c values between 6.2- 6-8 %, there was a particularly strong positive correlation with RDW values. In conclusion, there was a significant positive correlation between values of RDW and HbA1c, which emphasis that RDW is a good predictive factor for glycemic control.