The major form of glycohemoglobin is hemoglobin A1c (HbA1c). The HbA1c fraction is abnormally elevated in chronic hyperglycemic diabetic patients and correlates positively with glycemic control. Previous studies suggest that iron deficiency anemia (IDA) affects the levels of HbA1c. The aim of this study was to determine the effect of IDA on HbA1c levels in nondiabetic patients. The population studied consisted of 50 patients (30 women, 20 men, mean age 35.7 ± 11.9 years) with IDA and 50 healthy subjects that were matched for age and sex. Patients who had glucose tolerance abnormalities (impaired glucose tolerance or diabetes mellitus), hemoglobinopathies, hemolytic anemia, chronic alcohol ingestion and chronic renal failure were excluded from the study. Hematologic investigations, fasting and postprandial glucose and HbA1c levels were measured in all subjects before iron therapy. All patients with IDA were treated with iron 100 mg/day for 3 months. We repeated the laboratory investigation after iron therapy. Before iron treatment, the mean HbA1c (7.4 ± 0.8%) level in patients with IDA was higher than in a healthy group (5.9% ± 0.5) (p < 0.001). In patients with IDA, HbA1c decreased significantly after iron treatment from a mean of 7.4% ± 0.8 to 6.2% ± 0.6 (p < 0.001). Iron deficiency must be corrected before any diagnostic or therapeutic decision is made based on HbA1c.

De Rosa MC, Sanna MT, Messana I, Castagnola M, Galtieri A, Tellone E, Scatena R, Botta B, Botta M, Giardina B: Glycated human hemoglobin (HbA1c): Functional characteristics and molecular modeling studies. Biophys Chem 1998;72:323–335.
Peterson KP, Pavlovich JG, Goldstein D, Little R, England J, Peterson CM: What is hemoglobin A1c? An analysis of glycated hemoglobins by electrospray ionization mass spectrometry. Clin Chem 1998;44:1951–1958.
Shapiro R, McManus M, Garrick L, McDonald MJ, Bunn HF: Nonenzymatic glycolisation of human hemoglobin at multiple sites. Metabolism 1979;28(suppl):427–430.
Powers AC: Diabetes mellitus; in Braunwald E, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL (eds): Harrison’s Principles of Internal Medicine, ed 15. New York, McGraw-Hill, 2001, vol 22, pp 2105–2109.
UK Prospective Diabetes Study Group: Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes. Lancet 1998;352:837–853.
Ioannou GN, Spector J, Scott K, Rockey DC: Iron deficiency and gastrointestinal malignancy. A population-based cohort study. Am J Med 2002;113:281–287.
Wu AC, Lesperance L, Bernstein H: Screening for iron deficiency. Pediatr Rev 2002;23:171–178.
Brooks AP, Metcalfe J, Day JL, Edwards MS: Iron deficiency and glycosylated haemoglobin A1. Lancet 1980;19:ii:141.
Hansen PG, Eriksen J, Andersen TM, Olesen L: Glycosylated hemoglobin (HbA1c) in iron and vitamin B12 deficiency. J Intern Med 1990;227:133–136.
Van Heyningen C, Dalton RG: Glycosylated haemoglobin in iron-deficiency anaemia. Lancet 1985;i:874.
Rai KB, Pattabiraman TN: Glycosylated haemoglobin levels in iron-deficiency anaemia. Indian J Med 1986;83:234–236.
El-Agouza I, Abu Shohla A, Sirdah M: The effect of iron deficiency anaemia on the levels of haemoglobin subtypes: possible consequences for clinical diagnosis. Clin Lab Haematol 2002;24:285–289.
Tarim O, Kucukerdogan A, Gunay U, Erol P, Ercan I: Effects of iron-deficiency anemia on hemoglobin A1c type 1 diabetes mellitus. Pediatr Int 1999;41:357–362.
Stetler C, Mueller B, Diem P: What you always wanted to know about HbA1c. Schweiz Med Wochenschr 2000;130:993–1005.
Edelman SV: Importance of glucose control. Med Clin North Am 1998;82:665–687.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.