title: Effect of iron deficiency anemia and iron supplementation on HbA1c levels - Implications for diagnosis of prediabetes and diabetes mellitus in Asian Indians.
abstract: BACKGROUND
  We investigated the effect of iron deficiency anemia (IDA) on levels of glycated hemoglobin (HbA1c) and to compare its levels before and after iron supplementations.
  
  
  METHODS
  Age and sex matched subjects were enrolled and clustered in 2 groups: IDA (n=62) and healthy controls (HC; n=60). HbA1c levels were estimated by HPLC. Hemogram were estimated by hematology analyser. Serum ferritin (ELISA) and other parameters of iron profile were measured by standard guidelines of ICSH. HbA1c values and iron studies were repeated after 3months of iron supplementation to determine the effect of iron therapy on HbA1c levels.
  
  
  RESULTS
  Significantly higher HbA1c levels were observed in IDA subjects compared to HC (5.51±0.696 v/s 4.85±0.461%, p<0.001). A significant negative correlation was observed between HbA1c and hemoglobin, hematocrit, RBC count, MCH, MCHC and serum ferritin in IDA subjects (r=-0.632, -0.652, -0.384, -0.236, -0.192 and -0.441). Significant decline was noticed in HbA1c levels in IDA subjects after iron supplementation (5.51±0.696 before treatment v/s 5.044±0.603 post-treatment; p<0.001). Post treatment, 70% subjects (14/20) with HbA1c in pre-diabetes range normalised to normal glucose tolerance (NGT) range and out of 6 patients with pre-treatment HbA1c in diabetes range, 5 reverted to pre-diabetes range while 1 of them reverted to the NGT range.
  
  
  CONCLUSIONS
  Caution must be exercised in interpreting the results of HbA1c in patients of IDA and iron deficiency must be corrected before diagnosing diabetes and pre-diabetes solely on the basis of HbA1c criteria.
authors.affiliation: Departments of Medicine, University College of Medical Sciences (University of Delhi), G.T.B. Hospital, Dilshad Garden, Delhi 110095, India. Electronic address: svmadhu@yahoo.com.
authors.forename: S V
authors.initials: SV
authors.lastname: Madhu
authors.affiliation: Departments of Medicine, University College of Medical Sciences (University of Delhi), G.T.B. Hospital, Dilshad Garden, Delhi 110095, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Raj
authors.affiliation: Departments of Biochemistry, University College of Medical Sciences (University of Delhi), G.T.B. Hospital, Dilshad Garden, Delhi 110095, India.
authors.forename: Stuti
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Departments of Medicine, University College of Medical Sciences (University of Delhi), G.T.B. Hospital, Dilshad Garden, Delhi 110095, India.
authors.forename: S
authors.initials: S
authors.lastname: Giri
authors.affiliation: Departments of Pathology, University College of Medical Sciences (University of Delhi), G.T.B. Hospital, Dilshad Garden, Delhi 110095, India.
authors.forename: Usha
authors.initials: U
authors.lastname: Rusia
mesh_terms: D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000150:complications*; D016477:Artifacts; D016022:Case-Control Studies; D019587:Dietary Supplements; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007194:India; D007501:Iron / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood / Q000150:complications* / Q000175:diagnosis*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D006442:Glycated Hemoglobin; D007501:Iron
keywords: Diabetes mellitus; HbA1c; Iron deficiency anemia