[Therapy of endemic goiter with levothyroxine and iodide. A multicenter study].

74 patients suffering from diffuse endemic goitre and with peripheric euthyrotic metabolism were treated for 6 months either with 150 micrograms levothyroxine (T4) daily (group I, n = 35), or with a combination of 100 micrograms levothyroxine and 130.8 micrograms potassium iodide (corresponding to 100 micrograms iodide) daily (group II, n = 39). This was followed in each case by a 3-month prophylactic administration of 100 micrograms iodide daily. After 3, 6 and 9 months the reduction of the goitre volumes--measured by sonography--was significantly different from the initial value in both groups. The reduction in goitre size was more marked in group II (-30.3%) than in group I (-25.2%), in each case after 6 months' treatment, but this difference was not significant. Suppression of the basal TSH levels in the serum coincided almost completely in both groups with an equidirectional increase after the subsequent iodide administration of 3 months' duration. Whereas in group I there was a renewed tendency towards thyroid enlargement under iodide prophylaxis, the diminution effect obtained in group II remained unchanged.