Glycosylated Hemoglobin among Non-diabetic Patients Diagnosed as Benign Thyroid Lesions on Cytology: A Cross Sectional Study from a Tertiary Care Centre in India

Abstract

Background: Hypothyroidism and diabetes usually coexist and are the most common endocrine disorders seen in India (1). Glycosylated Hb (HbA1c) is used for assessment of glycemia and American Diabetic Association (ADA) has recommended its use in diabetes and prediabetes (2). A value between 5.7% and 6.5% represents prediabetes while a value ≥6.5% is considered as diabetes mellitus (3). Glycosylated hemoglobin is a fraction of hemoglobin that undergoes non-enzymatic glycation over the circulatory life span of erythrocytes (4). Several studies have shown glycosylated Hb varies in different conditions like hemoglobinopathies, pregnancy and chronic kidney disease (5). Thyroid hormone plays an important role in glucose homeostasis (6). TSH regulates hematopoiesis in bone marrow (7). Hypothyroidism depresses the marrow which causes decreased erythrocyte production which alters the life span of erythrocytes. Altered life span causes spurious elevation of HbA1C (8, 9, 10). Hence, glycosylated Hb not only depends on glycemia but also on life span of RBC (11). Conditions which effect erythrocyte turnover or survival lead to falsely high or low Hb A1C levels (12). RBC turnover is increased in thyrotoxic states whereas hypothyroidism has the opposite effect (3). In the present study, we hypothesise that glycosylated hemoglobin shows variation in individuals with altered thyroid status. It also aim to establish if a correlation exits between fasting plasma glucose level and hemoglobin with glycosylated hemoglobin in patients with altered thyroid status. Aims and Objectives: To find a correlation between thyroid profile and glycosylated Hb in non-diabetic patients who have been diagnosed on cytology as benign thyroid lesions and Compare the fasting blood glucose and hemoglobin with glycosylated Hb in these patients. Material and Methods: A cross sectional study on 50 cases cytologically diagnosed as benign thyroid lesions in the Department of Pathology in ESIC Medical College and Hospital Faridabad were included in the study with consent of ethical committee. Data Analysis: Pearson’s coefficient was applied to test the association between variables. The significance level was set at 5%. Results: Out of 50 patients (n=25) 50% were hypothyroid, (n=13) 26% were hyperthyroid and (n=12) 24% were euthyroid and (n=22) 88% hypothyroid patients presented with HbA1C >6.5% and were labeled as Diabetic, (n=3) 12% hypothyroid patients were labelled as prediabetic and none was nondiabetic. Most of the euthyroid (n=11) 92% and all of the hyperthyroid patients (n=13) 100% had HbA1C in the nondiabetic range of 6.5%). The correlation of HbA1C with TSH, Hb and MCH of these patients showed statistical significance (p 6.5%) or prediabetic (HbAIc between 5.7 to 6.5%).