Effect of Iron deficiency anemia on glycated hemoglobin levels in non-diabetes patients: Prospective Case-Control study

Abstract

Background: Glycated hemoglobin (HbA1c) has become the gold standard for the diagnosis and scale for measuring the glycemic control among the physicians. The level of HbA1c is influenced by several factors, including red blood cell turnover. There are various types of anemia that affect HbA1c readings, but iron deficiency anemia (IDA) is one of the most frequent. IDA has been shown to exhibit HbA1c readings that are greater than normal.Aims and objectives: To study the effect of IDA on HbA1c in subjects with normal fasting and postprandial blood glucose levels. Materials and Methods: Fifty subjects with IDA were studied attending OPDs in a tertiary care hospital, and findings were compared with a control arm having 50 subjects without anemia. Patients with IDA defined per WHO [Hb: <13.0 g/dl (adult males), <12 g/dl (non-pregnant women) and those with the microcytic, hypochromic picture in peripheral blood smear, serum ferritin <15 ng/ml suggestive of iron deficiency, subjects with normal fasting and postprandial plasma glucose level, normal blood urea and serum creatinine level were included. Patients who were being quantified underwent a comprehensive history, clinical examination, and pertinent biochemical examination, including HbA1c.Results: The study observed a statistically significant difference in Hba1c levels in non-diabetic patients withIDA compared with the normal population. The mean baseline serum ferritin level was significantly lower in patients with IDA than in controls (P<0.01). The mean HbA1C levels in patients with moderate anemia were 6.74. In severe anemia, the mean HbA1c was 7.07, significantly higher than the control group (P < 0.01). there was a significant negative correlation between the following parameters and Hba1C, which are Hb (r= -0.727), serum ferritin (r=-0.827) ,( r = -0.909), MCV levels ( r = -0.839), between % saturation ( r = -0.592). The study has shown a significant positive correlation between total iron-binding capacity and hbA1c levels (correlation co-efficient r = 0.743).Conclusion: HbA1c is not affected by blood sugar levels alone. There are various confounding factors when HbA1c is measured, especially iron deficiency, which is the commonest of the deficiency diseases worldwide. Hence, it is prudent to rule out IDA before making a therapeutic decision to treat diabetes mellitus based on the HbA1c levels.