Association of the Elevated Red Blood Cell Distribution Width with the Risk of Developing Diabetes Mellitus.

Objective The aim of this study was to determine whether elevated levels of RDW-coefficient of variation (CV) are associated with the development of diabetes mellitus (DM) in a population of healthy middle- and old-aged individuals. Method We conducted a retrospective cohort study. A total of 2,688 individuals (aged 49-66 years) without a DM diagnosis, impaired fasting glucose, or anemia at baseline were grouped according to the RDW-CV quartile, and the onset of DM during a 4-year period was recorded for each group. Results The correlation coefficients for the RDW-CV and waist circumference and for the RDW-CV and HbA1c were 0.114 and 0.133, respectively. The relative risks of future DM in RDW-CV quartiles II, III, and IV (high) compared with RDW-CV quartile I (low) were 1.9 [95% confidence interval (CI) 1.0-3.6, p=0.057], 1.6 (95% CI 0.8-3.0, p=0.157), and 2.2 (95% CI 1.2-4.0, p=0.015), respectively. After adjusting for sex, age, waist circumference, hemoglobin A1c, triglycerides, high density lipoprotein-cholesterol (HDL-C), and high-sensitivity C-reactive protein, the multivariate relative risk for the highest vs. the lowest RDW-CV quartile was 1.8 (95% CI, 1.1-3.4, p=0.046). Conclusion These data indicate that an elevated RDW-CV is associated with an increased incidence of DM.