A study of effect of iron deficiency anemia on glycosylated hemoglobin in non-diabetic patients
Authors: SK Sai , Prasad Manoj , S Priya , K Sivakumar 
Published: July 2024

Background: Diabetes mellitus is a rapidly increasing global health concern, having a substantial impact on morbidity and mortality. Glycated hemoglobin (HbA1c) is the primary measure of diabetes control, reflecting glycemic levels over the past 3 months. However, hemoglobin (Hb) abnormalities, such as those seen in iron deficiency anemia (IDA), can theoretically affect HbA1c levels. IDA, affecting over 30% of the global population, results from inadequate iron intake, hemorrhage, or poor iron absorption, leading to reduced Hb production. This study aims to evaluate the impact of IDA on HbA1c levels in non-diabetic patients, providing insights into accurate HbA1c interpretation in anemic patients.

Aims and Objectives: The study aimed to determine the impact of IDA on HbA1c levels in non-diabetic individuals.

Materials and Methods: This cross-sectional study was conducted over 6 months at Trichy SRM Medical College Hospital and Research Center. There were a total of 100 IDA patients and 100 age- and sex-matched healthy controls. Hb levels below 10 g/dL with a microcytic image suggestive of iron deficiency, postprandial blood sugar (PPBS) levels below 140 mg/dL following an oral glucose tolerance test (OGTT), and fasting blood sugar (FBS) levels below 100 mg/dL were the inclusion criteria. Exclusion criteria included Hb levels above 10 g/dL, altered FBS or PPBS values post-OGTT, diagnosed Type 2 diabetes mellitus, individuals younger than 18 years, and those with conditions such as hemoglobinopathies, hemolytic anemia, hypothyroidism, pregnancy, or abnormal renal function tests. Ethical approval and informed consent were obtained. Data collection included demographics, medical history, and laboratory investigations. Statistical analysis was performed using SPSS version 26, with t-tests, mean, and standard deviation (SD) for association analysis, and Chi-square tests for sex comparisons. Correlations were assessed through t-test. The significance level was kept at 0.05.

Results: The study confirmed that both groups met the inclusion criteria for non-diabetic status. The control group exhibited normal Hb levels, whereas the study group had Hb levels indicative of IDA. General and systemic examination findings were normal in both groups. Significant differences were observed across all measured parameters, with Hb levels, serum ferritin, mean corpuscular volume, mean corpuscular Hb, mean corpuscular Hb concentration, and red cell distribution width significantly lower in the study group. HbA1c levels were significantly elevated in the study group compared to the control group (5.87 ± 1.25 vs. 4.97 ± 1.59, P < 0.001), supporting the hypothesis that IDA is associated with elevated HbA1c levels in non-diabetic patients.

Conclusion: The study’s findings align with previous research indicating that IDA leads to elevated HbA1c levels. The prolonged erythrocyte survival and altered Hb glycation processes in IDA are likely contributors to this elevation. These results emphasize the need to consider anemia status when interpreting HbA1c values to avoid misdiagnosis and inappropriate management of diabetes. Clinicians should ensure comprehensive evaluations, including iron status assessments when encountering unexpectedly high HbA1c levels in non-diabetic individuals.