Treatment of endemic goitre due to iodine deficiency with iodine, levothyroxine or both: results of a multicentre trial.

Preliminary clinical studies and recent in vitro investigations suggest that iodine administration may be an effective alternative in the treatment of the diffuse euthyroid goitre of iodine deficiency. Therefore a 12-month multicentre study was initiated in which 166 patients were randomly assigned to take either 150 micrograms levothyroxine day-1 (group A, n = 61), 400 micrograms iodine day-1 (group B, n = 50), or a combination of 75 micrograms levothyroxine and 200 micrograms iodine day-1 (group C, n = 55) for 8 months with follow-up examinations at 4 and 8 months as well as 4 months after cessation of treatment. Initially, thyroid volume, as determined by ultrasound, was not significantly different in the three groups. In all three groups, during treatment a significant and comparable mean decrease in goitre size was documented (-32.1% in group A, -37.3% in group B, -38.7% in group C). After cessation of treatment in group A mean thyroid volume again increased to near the baseline value (-12.0% compared to the initial investigation), while the therapeutic effect was sustained in group B (-32.5%). In group C, only a slight rebound effect was observed (-26.3% vs baseline volume). Total thyroxine (T4) increased sharply and significantly in group A from 7.8 +/- 1.9 to 10.9 +/- 2.8 micrograms dl-1 after 8 months (P less than 0.001), but only slightly, although significantly in group B (from 7.8 +/- 1.5 micrograms dl-1 to 8.9 +/- 1.6 micrograms dl-1; P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)