Impact of Thyroid Dysfunction on Insulin Resistance: A Study from a Tertiary Care Center in India

The thyroid hormones perpetuate a fine equilibrium of glucose metabolism. Abnormalities of thyroid function can disrupt this balance leading to glucose metabolism abnormalities and insulin resistance.

We studied the correlation between insulin resistance and thyroid status in hyperthyroid, euthyroid, and hypothyroid individuals.

In this observational comparative analysis conducted at a tertiary care center, the 3 study groups comprised of 35 patients each with newly detected hyperthyroidism, hypothyroidism and euthyroid individuals. Assays were conducted for serum insulin, thyroid profile, blood sugar and routine biochemistry in the fasting state. The homeostasis model assessment for insulin resistance (HOMA-IR) was used to evaluate insulin resistance.

The mean HOMA-IR was highest in patients with hypothyroidism (3.22 ± 2.69) followed by the hyperthyroid group (2.25 ± 1.59). It was lowest in the euthyroid group (0.79 ± 0.58) with the intergroup difference being statistically significant (P<0.001). Hypothyroid patients showed a significant a positive correlation between TSH and HOMA-IR (r=0.945, P=<0.001) whereas hyperthyroid patients showed positive correlation between FT3 and insulin resistance (r=0.706, P<0.001).

Thyroid dysfunction is associated with an increase in insulin resistance and glucose abnormalities validating the resultant higher risk of related cardiovascular and metabolic abnormalities observed in these patients.