Glycated haemoglobin values in subjects affected by iron deficiency anaemia

Several studies suggest an association between iron deficiency anaemia and higher glycated haemoglobin (HbA(1c)) levels, but the results are conflicting and the matter is still under debate. We conducted a retrospective case-control study to investigate the effects of iron deficiency on HbA(1c) levels in subjects with iron deficiency anemia. Laboratory data were collected from a sample of individuals consecutively assessed from January 2000 to November 2016 in the Hospital of Desio, Lombardia, Italia. All non-pregnant subjects aged >12 years with one HbA(1c) measurement, a complete blood count, fasting blood glucose, and ferritin values within the same blood collection were enrolled for the study. A total of 2,831 subjects met the study criteria. Eighty-six individuals were diagnosed as affected by iron deficiency anemia, while 2,745 had normal iron, ferritin, and hemoglobin values. The adjusted mean of HbA(1c) was significantly higher in subjects with iron deficiency anemia (37,37 mmol/mol [5,59%]), compared to the one measured in individuals without anemia (34,81 mmol/mol [5,34 %]) (p < 0,0001). Our results confirm that iron deficiency anemia affects the levels of HbA(1c), significantly increasing them.