Endocrine Abstracts

Introduction

Anti-thyroid drugs (ATDs) are the first line treatment in Europe for hyperthyroidism due to Graves’ disease (GD). Adding levothyroxine to ATDs, so called block and replace therapy (BRT) is still controversial.

Aim

To follow up the outcomes after treating patients with Graves’ disease in a block and replace regimen.

Patients & methods

A prospective study which enrolled 33 patients with Graves’s disease, from 1st January 2020 until 28th January 2021. Inclusion criteria were: age > 18 years, new diagnosis of hyperthyroidism due to GD, patients with GD following block and replace therapy. Exclusion criteria were: age<18 years, pregnancy, GD treated with radiotherapy or surgical. Recorded data at diagnosis and each visit in the hospital were regarding to thyroid function tests (TSH (N:0.5–4.5 mUI/l), fT4 (N:9–19 pmol/l), T3 (N:80–200 ng/ml)) and specific thyroid antibodies (TRAb (N:<1.75 IU/l)), thyroid ultrasonography, level of 25OH-vitamin D. Data were recorded in Microsoft Excel and analyzed in Minitab v19.

Results

28 women, aged 44.32±12.54 years and 5 men, aged 54.6±18.6 years were included. New diagnosis of GD was made for 16 women and 4 men, the rest of them were already in a BRT. The group was characterized by insufficient levels of vitamin D (mean: 20.35±9.19 ng/ml, range 7.1–35 ng/ml). At diagnosis: TSH=0.0076 ±0.0107 mUI/l; TRAb=16.2±11.8 UI/l. BRT had a mean dose of 18±17.85 mg per day of Methymazole and 38.24±23.58 mg/day of Levothyroxine. From diagnosis to first visit in a BRT, fT4 decreases from a mean of 38.6±23.2 pmol/l to 14.59±8.31 pmol/l (P < 0.05), but it was in normal range. During BRT, TRAb titer decreased from 11±13.3 UI/l at first visit to 8.6±13.3 UI/l at the second visit in the Institute. One patient had adverse reaction to Methymazole so she was switch to Propylthyouracil. The volume of thyroid gland measured by ultrasound was 25.35±13.03 cm³. Twelve patients associated Graves’ ophthalmopathy, but only two of them needed steroids.

Limitations

Small number of patients, limited time for observation, heterogeneous group (patients newly diagnosed with GD, patients in BRT for more than 6 months).

Conclusion

BRT can maintain normal levels of TSH and fT4 and can decrease TRAb levels using combined Methymazole and Levothyroxine.