Glycemic status in patients with primary hypothyroidism and its relation to disease severity

Abstract

Background: Primary hypothyroidism can be defined as an increase in serum thyroid-stimulating hormone (TSH) level, and the concentration of free T3, free T4, T3, and T4 is low. Hypothyroidism is a prevalent disease mostly affecting middle-aged women. One of the most important determinants of glucose homeostasis is thyroid hormones. Hypothyroid patients have a higher prevalence of insulin resistance and tendency to Type 2 diabetes mellitus than the normal individual. Objective: To investigate the correlation between TSH and hemoglobin A1c (HbA1C) in patients with primary hypothyroidism; so, to study the effects of hypothyroidism on glucose metabolism. Subjects and Methods: Ninety-five Iraqi primary hypothyroidism patients and 40 healthy persons taken as control were selected from Specialized Centre for Endocrinology and Diabetes during the period from June 2017 to January 2018. The patients were diagnosed previously as cases of primary hypothyroidism, and they were on treatment and still on treatment. All patients were sent to investigate TSH, T4, T3, and HbA1c. The patients were subdivided into three main groups: first is uncontrolled nondiabetic primary hypothyroid group (36 patients), second is controlled nondiabetic primary hypothyroid group (43) and third is the diabetic primary hypothyroid group (16 patients). Results: A significant difference (P < 0.05) between HbA1C% in both controlled and uncontrolled hypothyroid groups against the control group, but there is no significant difference (P = 0.08) between the controlled and uncontrolled hypothyroid groups. The TSH relation with HbA1c was found to be significantly positive in the uncontrolled hypothyroid and diabetic, hypothyroid groups (r = 0.401 and 0.58, respectively). Conclusions: Significant increment was found in the level of HbA1c in hypothyroid patients, whether it is controlled or uncontrolled and a positive relationship was observed between TSH and HbA1c% in the uncontrolled and diabetic hypothyroid groups. Diabetes augments the effects of hypothyroidism on HbA1c.