Endocrine Abstracts

Introduction: Several levothyroxine (LT4) monotherapy dose regimen have been already proposed by different medical scientists which may result in various daily LT4 doses. Comparing the consequences of such dose regimen are rather difficult since they have to be applied on either the same patient or a large study groups. Therefore, a straight forward method would be to simulate the plasma level of thyroid hormones of virtual-patients treated by various dose regimen.

Method: In this study, the resulting plasma levels of thyroid hormones were compared for a total thyroidectomized virtual-patient treated by BMI and BSA-based LT4 monotherapy dose regimen adopted from Elfenbein et al., 2016 and Al-Dhahri et al., 2019 respectively. Our virtual-patient was considered as a 37 years old male with 72 kg weight and 170 cm height. The BMI of this patient would be 24.9 kg/m^2 while the calculated BSA based on DuBois & DuBois method is 1.83 m^2. In order to evaluate patient responses to LT4 monotherapy dose regimen, we simulated our total thyroidectomized virtual-patient by setting T3 and T4 secretion parameters at 1% using THYROSIM 3.0 while receiving static oral LT4 dosages post-surgery. In addition, with an assumption that no supplement was administrated, the absorption rate of oral LT4 was set to 88%.

Results: Considering the proposed dose regimen by BMI and BSA our virtual-patient should receive static LT4 dose of 1.9 and 1.4 μ g/kg respectively. Parameters to compare these two dose regimen for a period of 30-days are presented in the following table.

Conclusion: the BMI dose regime shows some superiority over BSA method especially in terms of lower time to reach normal TSH level and the discrepancy between TSH at day 30 and normal TSH. At the end of 30-days treatment period our virtual patient experiences a plasma T4 level of 86.56 and 68.26 μg/l if administering LT4 doses based on BMI and BSA methods.