The impact of sickle cell trait on glycated haemoglobin in diabetes mellitus.

Aims: To determine the effect of sickle cell trait on measurement of glycated haemoglobin (HbA(1c)) in African American patients with diabetes mellitus.

Methods: This is a retrospective study including 885 outpatients who underwent HbA(1c) testing. Medical record review and sickle cell trait determinations based on the HbA(1c) assay were performed in African American participants. The relationship between HbA(1c) and serum glucose measurements was analysed.

Results: Data were obtained from 385 AA (109 with SCT, 22 with haemoglobin C trait and 254 without haemoglobinopathy) and 500 European American patients. In a model created through multivariate repeated-effects regression, the relationship between HbA(1c) and simultaneous serum glucose did not differ between African American subjects with and without the sickle cell trait, but differed between African American subjects without the sickle cell trait and European Americans (P = 0.0002).

Conclusions: Sickle cell trait does not impact the relationship between HbA(1c) and serum glucose concentration. In addition, it does not appear to account for ethnic difference in this relationship between African Americans and whites.