Clinical Thyroidology February 2013 Entire Issue - American Thyroid ...

Clin Thyroidol 2013;25:33–34.Is Serum TSH Not the GoldStandard for Thyroxine Treatment?Albert G. BurgerClinicalTHYROIDOLOGYHoermann R, Midgley JE, Larisch R, Dietrich JW. Is pituitary thyrotropin an adequate measure of thyroidhormone-controlled homeostasis during thyroxine treatment? Eur J Endocrinol. November 26, 2012[Epub ahead of print].SUMMARYBackgroundThis article is complementary to several recent articles,one from the authors of the current article and onerecently reviewed by me in Clinical Thyroidology(1-3). The authors raise the question of whether thecurrent approach, monitoring thyroxine treatmentwith the serum TSH alone, is adequate. To answer thisquestion, they studied serum FT 4 and FT 3 levels in thyroxine-treatedpatients and compared them with thoseof untreated subjects.MethodsThe study was done between October 2006 andJanuary 2007. The first blood samples of 1994 patientsseen in a thyroid clinic were studied. The median ageof the patients (predominantly women) was 61 years.Thyroid antibodies were not measured routinely. Atotal of 1059 patients were untreated—they did notreceive any thyroid hormone or other drug treatment;50 patients were given iodine supplementation alone(100 to 200 µg per day). Of the 190 patients with hypothyroidism,only 53 (28%) had autoimmune disease;in the rest of the group, hypothyroidism was due tosurgery and radioactive iodine treatment.The patients were treated with 50 to 200 µg of levothyroxinedaily. Subclinical hyperthyroidism wasdefined by a serum TSH below the reference range(