Factors affecting thyroid function after subtotal thyroidectomy for Graves' disease: case control study by remnant-weight matched-pair analysis.

In order to determine whether there are any predictive factors, other than the amount of remnant thyroid tissue, for subsequent thyroid function after subtotal thyroidectomy for Graves' disease, thyroid function was assessed in 329 patients 3 years after surgery, and a case control study was carried out in euthyroid, hyperthyroid, and hypothyroid groups by remnant-weight matched-pair analysis. Factors that affected thyroid function 3 years after surgery were thyroid gland infiltration by lymphocytes and the thyrotropin binding inhibiting immunoglobulin (TBII) value in the hyperthyroid and euthyroid groups, and the free triiodothyronine (FT3) value at the time of surgery and lymph follicle formation in the thyroid gland in the hypothyroid and euthyroid groups. It is concluded that no single factor studied at surgery, other than the amount of remnant tissue, can predict thyroid function after subtotal thyroidectomy for Graves' disease.