Endocrine Abstracts

Objectives: The use of levothyroxine (LT4) treatment aiming to improve fertility in euthyroid women with positive thyroid peroxidase antibodies (TPOAb), is not supported by the available evidence, however the extent to which this is applied in clinical practice is unknown. The aim of the study was to document the demographic, work-related characteristics, and therapeutic choices of European physicians in the case of euthyroid infertile women positive for TPOAb.

Methods: The data presented here derive from THESIS (Treatment of Hypothyroidism in Europe by Specialists, an International Survey). THESIS developed and used a questionnaire to document the management of hypothyroidism by physicians in European countries. Twenty-eight out of the 29 invited Countries (all in Europe plus Israel and Turkey) accepted to participate. The questionnaire included eight questions about respondent characteristics and 23 questions about the use of thyroid hormones in different clinical settings. Here, we report the results on the use of thyroid hormones in infertile euthyroid women with positive TPOAb.

Results: Physicians (n=16,733) were invited via national endocrine societies to participate; 5,406 valid responses were received. Almost half (2316/5406, 42.8%) of all respondents replied that thyroid hormones may be indicated in biochemically euthyroid patients with female infertility with high level of thyroid antibodies. The proportion of physicians responding positively to this question varied across countries between 23 and 84% (median=41%). In multivariate analysis male gender (OR: 0.8; CI: 0.7-0.9) and respondents older than 60 years (age >60 OR: 0.7; 0.6-0.8) were least inclined to prescribe LT4 for this indication. Conversely respondents with a high workload of thyroid patients [“weekly” (OR: 1.4; CI: 1.0-1.9), “daily” (OR: 1.9; CI: 1.4-2.5)] and practicing in Eastern Europe (OR: 1.6; CI: 1.3-1.9) were most likely to prescribe LT4 to euthyroid infertile women. Respondents’ age, gender and geographical location had a striking impact: middle-aged female thyroid physicians practicing in Eastern Europe were seven times more likely to prescribe LT4 for euthyroid, infertile, TPOAb positive women than older male thyroid physicians practicing in Northern Europe (OR: 7.0; CI: 5.4-8.9).

Conclusions: Notwithstanding current evidence against systematic treatment, a remarkable number of thyroid specialists would use LT4 for euthyroid, infertile women with positive TPOAb. This practice varied widely across countries and correlated with sex, age, workload, and geography, significantly influencing the patient’s management. Our study draws attention to the intriguing associations between clinical decisions and physician demographic characteristics.