Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2009) 19 P242

SFEBES2009 Poster Presentations Pituitary (56 abstracts)

An analysis of the dose of levothyroxine in patients with central hypothyroidism

Fabrizio Diacono , Ismene Bilbao , Niki Karavitaki & John AH Wass


Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, Oxfordshire, UK.


Background: Levothyroxine is the standard treatment for central hypothyroidism (CH). Studies assessing the optimal dose are limited and include subjects with other untreated pituitary hormone deficits, affecting the interpretation of results. A reliable comparison with the dose used in primary hypothyroidism (PH) has not been reported.

Aims: To evaluate daily and body-weight-adapted levothyroxine dose (BWA-dose) in a cohort of patients with CH on appropriate replacement for concomitant pituitary deficiencies and to compare the dose in subjects with CH and PH matched for age, gender, BMI and FT4.

Patients and methods: Seventy-one patients (41 males, age 53.1±14.6 years) with CH and normal FT4 on a stable levothyroxine dose for at least 8 weeks were retrospectively reviewed. Other pituitary deficiencies were adequately treated. A subgroup of 65 subjects was compared with 65 patients with PH on levothyroxine and normal FT3, FT4 and TSH.

Results: In CH, median levothyroxine dose was 100 μg/day (range 50–225) and mean BWA-dose was 1.33±0.4 μg/kg per day. Patients with FT4 in upper-half of reference range received higher BWA-dose than those with FT4 in lower half: 1.45±0.4 vs 1.2±0.4 μg/kg per day (P<0.05). The BWA-dose negatively correlated with age and BMI (r=−0.325; P<0.01/r=−0.298; P<0.01, respectively). Patients with BMI>30 kg/m2 or age>65 were replaced with a lower dose compared with those with BMI<30 kg/m2 (P<0.005) or age<65 (P<0.01).

Comparison between CH and PH subjects did not reveal difference in levothyroxine dose.

CHPH
Males/females37/2837/28
Age; BMI kg/m253.8±13.2;53.4±14NS
29.3±5.329.2±4.8
FT4 pmol/l TSH17.3±2.417.5±2.3NS
median (range) mIU/l2.29(0,35–5,28)
BWA LT4 μg/kg per day1.33±0.41.37±0.5NS

Conclusions: Patients with CH on appropriate replacement of other pituitary hormone deficits require mean levothyroxine BWA-dose of 1.45±0.4 μg/kg per day to achieve FT4 within the upper half of normal range. The mean BWA-dose to achieve FT4 within reference range does not differ from that required for adequate replacement in PH.

Article tools

My recent searches

No recent searches.