Evaluation of thyroid function in type 2 diabetes in north-eastern part of India: A hospital-based study

Diabetes mellitus (DM) and thyroid dysfunctions are the two most common endocrine disorders to come across in any clinical practice. Both thyroid hormones and insulin act antagonistically in metabolic pathways or cycles of cells. The aim of our study is to look for thyroid dysfunction in patients with type 2 DM and its correlation with insulin resistance (IR).

A cross-sectional study was carried out among 80 newly diagnosed type 2 diabetic patients. Thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine, and insulin were measured in fasting serum sample. Homeostasis model assessment for IR was calculated as per formula.

Among 80 diabetic patients, 20 were hypothyroid, 4 were hyperthyroid, and 56 were found to be euthyroid. IR was found to be significantly higher in hypothyroid as compared to euthyroid patients. A positive association was found between TSH and IR (r = 0.230) among hypothyroid patients though association was not significant. In hyperthyroid patients, a strong negative correlation (r = -0.94933) was found between TSH and IR, but no association was found among euthyroid patients.

The inability to recognize the presence of thyroid hormone dysfunction may be one of the important causes of poor management of type 2 DM. Therefore, there is a need for routine assay of thyroid hormones in type 2 diabetic patients to improve the medical management as well as to reduce the morbidity in them.