In:
European Journal of Endocrinology, Oxford University Press (OUP), Vol. 173, No. 2 ( 2015-08), p. 247-256
Abstract:
Although it has been recommended that serum free thyroxine (FT 4 ) levels should be targeted to middle-upper normal levels during levothyroxine ( l -T 4 ) replacement therapy in patients with central hypothyroidism (CeH), the rationale has not been clarified. Methods A retrospective single-center study enrolled 116 patients with hypothyroidism (CeH, n =32; total thyroidectomy (Tx), n =22; primary hypothyroidism (PH), n =33; and control benign thyroid nodule (C), n =29). The patients had received l -T 4 therapy at the Kobe University Hospital between 2003 and 2013. They were stratified according to serum FT 4 level (≥1.10 or 〈 1.10 ng/dl), and body temperature (BT), serum free triiodothyronine (FT 3 ) levels, FT 3 /FT 4 ratio, and lipid profiles were compared. The effect of GH replacement therapy on thyroid function was also analyzed. Results FT 3 levels and FT 3 /FT 4 ratios were significantly lower in patients with CeH than in patients with PH ( P 〈 0.05) or C ( P 〈 0.05). In patients with FT 4 〈 1.10 ng/dl, BT was significantly lower in patients with CeH ( P =0.002) and Tx ( P =0.005) than in patients with PH, whereas no differences were found in patients with FT 4 ≥1.10 ng/dl. In patients with CeH, FT 3 levels were higher in those with GH replacement therapy ( P =0.018). Conclusion In CeH, patients with median-lower normal levels of serum FT 4 exhibited lower serum FT 3 levels and lower BT. These results support the target levels of serum FT 4 as middle-upper normal levels during l -T 4 replacement therapy in patients with CeH.
Type of Medium:
Online Resource
ISSN:
0804-4643
,
1479-683X
Language:
Unknown
Publisher:
Oxford University Press (OUP)
Publication Date:
2015
detail.hit.zdb_id:
1485160-X
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