FIG. 4.

Comparison of odds ratios for DTC among the different subgroups of patients affected by Hashimoto's thyroiditis (HT) and the Non-HT population based on TPO antibody status. Patients affected by HT were split by the TPO-Ab status (see Methods for details) into TPO-High (A) and TPO-Low/Negative (B). We found that the TPO-Low/Negative status conferred an increased risk for DTC in all groups except for the LT₄-Mid and LT₄-High. On the other hand, the TPO-High group was not significantly different compared to the Non-HT. Non-HT, patients unaffected by Hashimoto's thyroiditis on surgical pathology. TPO-AB, thyroid peroxidase antibodies; TPO-High, TPO-Ab titer>1:1000; TPO-Low/Negative, TPO-Ab titer<1:1000 or undetectable (negative); Euth-HT, euthyroid patients with Hashimoto's thyroiditis; LT₄, hypothyroid patients on levothyroxine replacement; Low/Mid/High, tertiles of levothyroxine replacement dose (see text for details).