Effect of iron deficiency anemia and iron supplementation on HbA1c levels - Implications for diagnosis of prediabetes and diabetes mellitus in Asian Indians

摘要

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 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. Highlights ? Recently HbA1c has been recommended as a sole diagnostic criterion for prediabetes & diabetes mellitus. ? Iron deficiency anemia (IDA) was associated with a significant increase in baseline HbA1c measured by HPLC. ? Iron supplementation significantly decreases HbA1c levels. ? Iron deficiency must be corrected before any diagnostic decision is made solely on the basis of HbA1c in areas with a high prevalence of IDA.