The Use of Thyroid Hormones in Hypothyroid and Euthyroid Patients: A THESIS* Questionnaire Survey of Turkish Physicians

Objective: The incidence of diagnosis of hypothyroidism and the use of thyroid hormones are progressively increasing worldwide. The availability of different thyroid hormone replacement formulations and combinations provides clinicians with various therapeutic choices. The aim of this survey is to document the current approaches of clinicians who manage patients with hypothyroidism in Turkey. Methods: Members of the Society of Endocrinology and Metabolism of Turkey were invited to take part in a web-based survey. Results: A total of 741 members, all clinicians, were invited to respond, and 193 (26%) of them completed the survey. Nearly all (95.9%) participants responded that they treat hypothyroid patients daily. All participants declared that the first treatment of choice for hypothyroidism is levothyroxine. Half of the participants (50.3%), 51.1%, responded that they would not consider using levothyroxine + liothyronine combination in routine clinical practice. Soft and liquid forms of levothyroxine (LT4) were not used as an alternative to tablets although about a quarter of clinicians responded that they would use them if marketed in Turkey. Although 39.4% of respondents estimated that the frequency of patients with persistent symptoms despite achieving euthyroid biochemistry had increased in the last 5 years, two-thirds of them (63.2%) stated that this group comprised less than 10% of all treated hypothyroid patients. Just under half of the respondents (40.3%) would consider thyroid hormone replacement in bio-chemically euthyroid patients. The commonest indication (25% of responders) for commencing thyroid hormone therapy in euthyroid patients was female infertility with high level of thyroid peroxidase antibodies. Only 6.8% of participants considered levothyroxine therapy for the treatment of simple goiter. Conclusion: Levothyroxine in tablet form is the treatment of choice for hypothyroidism in Turkey. Despite the absence of robust evidence, half of the clinicians indicated their preference for levothyroxine + liothyronine treatment in specific clinical scenarios. At variance with current guidelines, half of all clinicians would also consider levothyroxine replacement in euthyroid patients, especially thyroid peroxidase antibodies-positive females with infertility.