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 3 months 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 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 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.