Bao X, et al. – Using data from a prospective cohort study, the researchers intended to examine the relationship between red cell distribution width (RDW) and elevation of glucose/glycated hemoglobin (HbA1c). They found that elevated RDW was independently associated with future HbA1c elevation, but not to glucose elevation. They suggested that RDW might associate with HbA1c through a non–glycemic way, which should be taken into consideration when using HbA1c as a diagnostic criterion of prediabetes or diabetes.

Methods

• For the purpose of this study, individuals without prediabetes or diabetes (n=7,795) were followed for a mean of 2.90 years (range: 1~7 years, 95% confidence interval: 2.86-2.94 years).
• Glucose elevation is characterized as fasting glucose levels exceeding 5.6mmol/l, or 2-hour glucose values in the oral glucose tolerance test exceeding 7.8mmol/l.
• HbA1c elevation is characterized as a HbA1c value exceeding a normal limit of 39 mmol/mol (5.7%).
• Adjusted Cox proportional hazards regression models were utilized to evaluate the relationship between RDW quartiles and elevation of HbA1c/glucose.

Results

• The results of this study showed that the multiple-adjusted hazard ratios (95% confidence interval) of HbA1c elevation for increased quartiles of RDW were 1.00 (reference), 1.08 (0.89, 1.30), 1.28 (1.07, 1.54), and 1.54 (1.29, 1.85) (P for trend <0.0001).
• They did not find significant association between RDW and blood glucose (fasting and postprandial).