Increased red blood cell distribution width (RDW) is associated with higher glycosylated hemoglobin (HbA1c) in the...

The aim of the present study was to examine whether red blood cell distribution width may be associated with glycated hemoglobin (HbA1c) in a large cohort of unselected elderly Italian outpatients.

We performed a retrospective search on the database of the laboratory information system of the clinical chemistry laboratory of the General Hospital of Verona (Italy), to retrieve combined results of complete blood count (CBC) and HbA1c performed in outpatients aged 65 years or older during the year 2013.

Cumulative results of CBC and HbA1c could be retrieved for 2515 outpatients aged 65 years or older throughout the study period. In the entire population, HbA1c was significantly associated with RDW values (r = 0.11; p < 0.001), even after adjustment for age and gender. The concentration of HbA1c was significantly higher in patients with RDW > 14.0% than in those with RDW ≤ 14.0% (45 versus 43 mmol/mol; p < 0.001). The rate of HbA1c > 53 mmol/mol was greater among patients with RDW > 14.0% than among those with RDW ≤ 14.0% (19 versus 15%; p = 0.006). The odds ratio of an increased RDW value for HbA1c > 53 mmol/mol was 1.33 (95% CI, 1.08 - 1.65; p = 0.01).

The results of this retrospective analysis extend the previous finding that RDW is significantly associated with HbA1c to a large cohort of unselected and elderly southern European outpatients. Since RDW is a simple and inexpensive parameter, it may be regarded as a potential, innovative biomarker for improving risk assessment of developing diabetes.