Use of thyroid hormones in hypothyroid and euthyroid patients: a THESIS* questionnaire survey of Polish physicians *THESIS: Treatment of hypothyroidism in Europe by specialists: an international survey

Introduction: Over the past several years new evidence on the management of hypothyroidism has emerged, which has influenced recommendations from professional bodies. The presentation of hypothyroid patients has also changed, and new cases are increasingly diagnosed by indiscriminate screening, often identifying cases with minor biochemical disturbances. Little is known about the physician responses and attitudes to this changing landscape. THESIS (Treatment of Hypothyroidism in Europe by Specialists: an International Survey) is a large-scale survey of European physicians who treat patients with hypothyroidism. Here we document current practices of Polish physicians relating to the use of thyroid hormones in hypothyroid and euthyroid patients. Material and methods: Members of the Polish Society of Endocrinology were invited to participate in the web-based THESIS survey. Results: In total 423 (54.6% of the 774 invited) physicians completed the survey. The majority of respondents (74.2%) would prescribe thyroid hormones for euthyroid patients for certain indications, such as female infertility with elevated thyroid antibodies (63.4%), simple goitre (40.9%), unexplained fatigue (12.1%), obesity (9.7%), hypercholesterolaemia (9.0%), and depression (9.2%). Nearly all physicians (96.0%) declared that the treatment of choice for hypothyroidism is levothyroxine (LT4). However, around one-third (30.3%) were also using LT4 and liothyronine (LT3) combination treatment; LT3 alone was rarely prescribed (1.7%), and none prescribed desiccated thyroid extract. The majority of respondents preferred LT4 tablets. Among alternative formulations, liquid LT4 was most commonly recommended for patients unable to take LT4 in the fasting state (26.0%) and patients with malabsorption (19.9%). Respondents considered prescribing dietary supplements (such as selenium and iodine) in hypothyroid patients with coexisting autoimmune thyroiditis (29.6%) or at the patients' request (32.2%). LT4 + LT3 combination therapy was used by 32.2% when symptoms persisted notwithstanding normal serum TSH concentration. Psychosocial factors, comorbidities, and the burden of chronic disease were considered as the most likely causes of persistent symptoms. Conclusions: Apart from clinical practice recommendations, other factors influence the thyroid hormone therapy patterns. Moreover, certain areas of clinical practice were identified (the use of thyroid hormones in euthyroid subjects and the use of dietary supplements), which are not in accordance with the current evidence.