A comparison of Effect of Iron Deficiency Anemia on HbA1c Levels in Controlled Diabetics and Non-diabetics: A Cross Sectional Analysis of 300 Cases

Background: Diabetes Mellitus (DM) has become a major health problem worldwide. American Diabetes Association has considered HbA1C levels ≤ 6.5 % as the prime target for glycemic control and as a diagnostic criterion for DM. Anemia is common in DM (8-66%). Studies on alteration of HbA1C in IDA have conflicting results. Objectives: To identify and compare the effect of IDA on HbA1C levels among controlled diabetics (Fasting plasma glucose (FPG) <126mg/ dl since last 6 months) and non-diabetics and its variation according to the degree of anemia. Methods: This cross-sectional study done in SRM Medical College Hospital and Research Centre, Chennai includes 150 Controlled diabetics (75 with IDA and 75 without IDA) and 150 non diabetics (75 with IDA and 75 without IDA). HbA1C, complete hemogram, iron profile and FPG were tested. Medical history was recorded. Results: The mean HbA1C in controlled diabetics with and without IDA were 8.81±0.13 & 5.79±0.01 respectively (P<0.05) and in nondiabetics with and without IDA were 6.84±0.07 & 5.12±0.04 respectively (P<0.05). The difference between no, mild, moderate and severe anemia in both diabetics and non-diabetics was statistically significant (p< 0.05). Mean HbA1C% was highest in groups with severe anemia. Conclusion: IDA falsely elevates HbA1C level independent of blood glucose concentration in both controlled diabetics and non-diabetics. Hence prior to alteration of treatment regimen based on HbA1C for diabetes, IDA should be diagnosed and corrected. Concurrent evaluation for anemia is critical to correctly interpret glycemic status in Indian population with prevalent IDA.