Reduction of Thyroid Nodule Volume by Levothyroxine and Iodine Alone and in Combination: A Randomized, Placebo-Controlled Trial

Study answer

What this study found

The combination of iodine plus nonsuppressive levothyroxine produced the clearest benefit and was the only active regimen that significantly reduced total nodular volume. Change in total nodular volume after 12 months was -17.3% [95% CI -24.8 to -9.0], P<0.001 with T4+I, compared with -7.3% [95% CI -15.0 to 1.2], P=0.201 with T4 and -4.0% [95% CI -11.4 to 4.2], P=0.328 with iodine. T4+I was superior to T4 (P=0.018) and iodine (P=0.003). Thyroid volume also decreased with T4+I (-7.9% [95% CI -11.8 to -3.9], P<0.001), with smaller reductions for T4 (-5.2%, P=0.024) and no significant effect…

Study & population

Randomized, placebo-controlled, multicenter trial conducted at 60 German study centers in euthyroid adults with nodular goiter and one or more thyroid nodules.

Intervention

Iodine arm: potassium iodide 150 g per day; T4 arm: levothyroxine 75 g per day; T4+I arm: levothyroxine 75 g per day plus potassium iodide 150 g per day.

Key limitation

The trial followed patients for only 12 months, so longer-term durability and safety are uncertain.

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Original abstract