Abstract Introduction: Diabetes mellitus and anemia are among the most significant public health problems worldwide. The significant incidence of both diseases increases the probability of their coexistence in the same patient. This study investigated whether anemia types (microcytic, normocytic, and macrocytic) have any effect on glycated hemoglobin (HbA1c). Materials and Methods: The study included 40 patients with iron deficiency anemia (IDA; microcytic anemia), 40 patients with vitamin B12 deficiency (megaloblastic anemia), 18 patients with autoimmune hemolytic anemia (AHA; normocytic anemia), and 40 patients in the control group. The baseline hemoglobin (Hgb), mean corpuscular volume, fasting plasma glucose, and HbA1c values of patients meeting the inclusion criteria were measured, and the data for each study group were compared with those of the control group. Results: The Hgb value was significantly lower in the IDA, vitamin B12 deficiency, and AHA groups when compared separately with the control group ( P < 0.00, P < 0.001, and P < 0.001, respectively). HbA1c levels were significantly higher in the group with IDA and megaloblastic anemia compared to the control group, while they were significantly lower in the group with AHA compared to the control group ( P < 0.00, P < 0.001, and P < 0.001, respectively). Conclusion: Irrespective of the type of anemia (microcytic, normocytic, or macrocytic), HbA1c in anemic patients can lead to misinterpretation, misdiagnosis, or underdiagnosis, resulting in adverse outcomes. In anemic patients, using plasma glucose, glycosylated albumin, or fructosamine instead of HbA1c may be a more appropriate approach.
Manafova et al. (Fri,) studied this question.