Effects of altering levothyroxine (L-T4) doses on quality of life, mood and cognition in L-T4 treated subjects.

Effects of altering levothyroxine (L-T4) doses on quality of life, mood and cognition in L-T4 treated subjects.

J Clin Endocrinol Metab. 2018 Mar 02;:

Authors: Samuels MH, Kolobova I, Niederhausen M, Janowsky JS, Schuff KG

Abstract
Background: The brain is a critical target organ for thyroid hormone, but it is unclear whether variations in thyroid function within and near the reference range affect quality of life, mood, or cognition.
Methods: 138 subjects with L-T4 treated hypothyroidism and normal TSH levels underwent measures of quality of life (SF-36, ThyDQoL), mood (Profile of Mood States, Affective Lability Scale), and cognition (executive function, memory). They were then randomly assigned to receive an unchanged, higher or lower L-T4 dose in double blind fashion, targeting one of three TSH ranges (0.34-2.50, 2.51-5.60, or 5.61-12.0 mU/L). Doses were adjusted every 6 weeks based on TSH levels. Baseline measures were reassessed at 6 months.
Results: At end of study, by intention to treat, mean L-T4 doses were 1.50±0.07, 1.32±0.07, and 0.78±0.08 mcg/kg (p<.001), and mean TSH levels were 1.85±0.25, 3.93±0.38, and 9.49±0.80 mU/L (p<.001) in the three arms. There were minor differences in a few outcomes among the three arms which were no longer significant after correction for multiple comparisons. Subjects could not ascertain how their L-T4 doses had been adjusted (p=0.55), but preferred L-T4 doses they perceived to be higher (p<.001).
Conclusions: Altering L-T4 doses in hypothyroid subjects to vary TSH levels in and near the reference range does not affect quality of life, mood, or cognition. L-T4 treated subjects prefer perceived higher L-T4 doses despite a lack of objective benefit. Adjusting L-T4 doses in hypothyroid patients based on symptoms in these areas may not result in significant clinical improvement.

PMID: 29509918 [PubMed - as supplied by publisher]

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