Estimation Of Fructosamine And Glycated Hemoglobin In Newly Diagnosed Subclinical Hypothyroid, Clinical Hypo And Hyperthyroid Patients Without Diabetes Mellitus:A One Year Cross Sectional Study

Abstract

Thyroid disease is the most common endocrine disorder encountered in clinical practice,it can present as hypo, hyper or subclinical hypothyroidism. Circulating sugars, primarily glucose and fructose when they come in contact with proteins and lipids cause damaging reactions and forming compounds called Advanced Glycation End Products (AGEs).Fructosamine and Glycated Hemoglobin (HbA1c) known AGEs are useful indicators to measure the peripheral metabolic function in patients with thyroid disorder. We have undertaken this study to evaluate and correlate the role of Glycated Hemoglobin and Fructosamine in thyroid disorders. Materials And Methods This one year cross sectional study was done from January 2016 to December 2016 attending medicine (Endocrinology) Outpatient Department of KLE’S Dr Prabhakar Kore Hospital and Medical Research Centre, Belagavi. Newly diagnosed Subclinical hypothyroid,Clinical hypo and hyperthyroid patients were part of the study,along with age matched healthy individuals.The study consists of 110 subjects (80 cases+30 controls) who were included after obtaining informed and written consent.Suspected cases after clinical examination underwent TSH,T3,T4 investigations by Chemiluminescence method .After the confirmation of diagnosis,all the cases were asked to come in fasting state on the day of their choice and the FPG,Glycated Hemoglobin and Fructosamine assays were done.If FPG levels were more than reference interval (70-100 mg/dl) then those were excluded from the study. The study was conducted in four groups.30 participants in control or euthyroid group,20 patients in Subclinical Hypothyroid group,Clinical hypothyroid and hyperthyroid group which consisted of 30 patients each,of either age and sex aged 20-60 years. Results were tabulated and subjected to appropriate statistical analyses. Results: In subclinical hypothyroid group the mean FPG (88.80±2.59),HbA1c (5.32±0.38) and Fructosamine values (485±40.16) were high when compared with the controls by one way ANOVA.Pair wise comparison of FPG (p=0.009),HbA1c (p=0.001) and Fructosamine levels (p=0.001) with controls by Tukeys multiple Post-hoc Bonferroni test showed statistically significant difference. There was a positive significant correlation between FPG and HbA1c (r=0.4704) ,while there was no significant correlation between FPG and Fructosamine (r=0.1317) levels by Karl Pearson’s correlation coefficient method. In clinical hypothyroid group the mean FPG (89.23±4.44), HbA1c (5.44±0.14) and Fructosamine (576.77±37.33) levels were high when compared with the controls by one way ANOVA. Pair wise comparison of FPG ( p=0.001),HbA1c (p=0.001) and Fructosamine levels (p=0.001) with controls by Tukeys multiple Post-hoc Bonferroni test showed statistically significant difference. There was a positive significant correlation between FPG and HbA1c (r=0.466) and FPG and Fructosamine (r=0.421) levels by Karl Pearson’s correlation coefficient method. In clinical hyperthyroid group the mean FPG (93.67±0.92) and HbA1c (5.53±0.24) and low Fructosamine (269.43±7.90) levels when compared with the controls by one way ANOVA. Pair wise comparison of FPG (p=0.001), HbA1c (p=0.001) and Fructosamine levels (p=0.001) with controls by Tukeys multiple Post-hoc Bonferroni test showed statistically significant difference.There was a positive significant correlation between FPG and HbA1c (r=0.406) and negative correlation between FPG and Fructosamine (r=-0.437) ) levels by Karl Pearson’s correlation coefficient method. Interpretation and conclusion: In the present study Subclinical hypothyroid ,Clinical hypothyroid and Clinical hyperthyroid groups had higher levels of FPG when compared with the Controls.HbA1c and Fructosamine levels were higher in Subclinical hypothyroid and Clinical hypothyroid groups when compared with the Controls.However in clinical hyperthyroid group FPG and HbA1c levels were higher while Fructosamine levels were low when compared with the Controls which was statistically significant. The severity, prevalence and pathogenesis of abnormalities of carbohydrate metabolism in thyroid disorders are incompletely defined. To study the effect of thyroid hormones on glucose metabolism in non diabetic patients is an area for extensive research.Glycated Hemoglobin and Fructosamine could be useful indicators to measure the peripheral metabolic functions in patients with thyroid disorder. Hence we suggest HbA1c and Fructosamine could be included in the thyroid work up of the patients.