Assessment of glycated hemoglobin levels in non-diabetic subjects with recently diagnosed hypo and hyperthyroidism

Abstract

Background: Thyroid disorders are highly prevalent in the general population and generally manifest as hypothyroidism or hyperthyroidism. Glycated hemoglobin (HbA1c) is commonly used for the assessment of the long-term glycemic status of diabetic patients. But the HbA1c concentration not only depends on prime glycemia but some other factors. Aims and Objectives: The objective of this study was to measure glycated hemoglobin and thyroid hormone levels and aimed to determine the effects of hypo and hyperthyroidism on glycated hemoglobin in non-diabetic patients. Materials and Methods: This case-control study was conducted on 70 euglycemic individuals each newly diagnosed with hypo and hyperthyroidism. Seventy age and gender-matched controls were recruited. Baseline HbA1c was estimated by high-performance liquid chromatography (HPLC) and thyroid status was measured by chemiluminescent immunoassay (CLIA) method in all cases and controls and then compared. Results: HbA1c values were found to be significantly higher in the hypothyroid group (P < 0.001), whereby its values in hyperthyroid subjects showed no significant difference from controls (P = 0.17). A positive correlation (r=0.67) exists between the levels of thyroid-stimulating hormone (TSH) and HbA1c in hypothyroid patients, but no significant correlation (r= -0.07) was observed for hyperthyroid subjects. Conclusion: HbA1c may not be a reliable indicator of glycemic status in patients with hypothyroidism, and so HbA1c results should be interpreted with caution in such patients.

Keywords

• glycated hemoglobin
• hba1c
• hyperthyroidism
• hypothyroidism