Sustained Control of Hyperthyroidism in Graves' Disease: Comparison of Thyroidectomy and Long-Term Antithyroid...

The achievement of sustained euthyroidism in patients with Graves' hyperthyroidism may reduce the risk of mortality and cardiovascular events.

We compared the time to euthyroidism and the time remaining in euthyroidism following total thyroidectomy and long-term methimazole (LT-MMI) treatment.

In this prospective cohort study, two hundred and eight patients with diffuse toxic goiter, 104 (84 women) with total thyroidectomy, and 104 (84 women) on LT-MMI were compared. All patients received adequate levothyroxine treatment after thyroidectomy. Data on serum free thyroxine (fT4), triiodothyronine (T3), and thyrotropin (TSH) every 6 months until the end of follow-up were analyzed. The time to normalization of serum thyroid hormones and TSH concentrations and the percentage of time that thyroid hormones and TSH levels remained within the normal range during a mean follow-up of 11 years were compared between the two study groups using t-test, Mann-Whitney U, chi-square, and Fisher exact tests.

The mean time to euthyroidism was 4.74 ± 2.42 and 4.48 ± 2.54 months in the thyroidectomy and LT-MMI groups, respectively. During follow-up, the percentage of time spent in euthyroidism was 82.67 ± 7.33% vs 94.21 ± 6.98% in the thyroidectomy and LT-MMI groups, respectively (P < 0.001). Patients with thyroidectomy spent more time in subclinical and clinical hypo- and hyperthyroidism compared to LT-MMI patients. Permanent hypocalcemia and vocal cord paralysis occurred in 2 and 1 patients, respectively.

Treatment of hypothyroidism after total thyroidectomy was accompanied by less sustained euthyroidism during long-term follow-up compared with LT-MMI therapy. This difference may be important for the risk of mortality and cardiovascular events, demanding long-term studies for comparison of these outcomes in patients treated with total thyroidectomy and LT-MMI treatment.