LT4-monopreparation versus LT4- LT3-compound preparation in the treatment of diffuse endemic goitre

Fifty-four patients with diffuse non-toxic goitre were observed before and under therapy either with 125 μg LT4 (group A) or 75 μg LT4 + 15 μg LT3 (group B) in a prospective double blind study, using 1-, 3- and 6-months controls. Changes in goitre size have been estimated by ultrasonic scanning. Both treatment forms provided a significant reduction of goitre size, even after 1 month of therapy: a 20%-decrease in group A and 16% in group B. The 6-month reduction was about 30% in group A and 27% in group B. Between the 2 groups there were no differences in the reduction of volume. The suppression of the TSH-response to TRH was identical in both groups, too. In group A there was a predominant increase of the TT4-and FT4-serum levels, both reaching the hyperthyroid range. In group B there was a predominant increase of the TT3- and FT3-serum levels and a slight increase of the FT4-levels. The TT3- and FT3-serum levels also exceeded the upper normal range. As the blood samples were drawn about 2 h after medication, acute hormone resorption influenced these data. In the 3-month controls only there was a significant correlation between the reduction of the thyroid volume and the suppression of TSH-release. In the 6-month controls we found a weak correlation of the reduction of volume and the decrease of the pertechnetate uptake value. No correlation was found between the relative changes of FT3- and FT4-serum levels and the reduction of goitre size. There were no indications of possible side effects in group A or B during treatment. So this study showed the compared treatment forms to be equivalent in the therapy of diffuse non-toxic goitre, both yielding excellent results.