Endocrine, cilt.91, sa.1, 2026 (SCI-Expanded, Scopus)
Background and objective: The relationship between quality of life (QoL) and thyroid stimulating hormone (TSH) levels in patients receiving levothyroxine (LT4) therapy is unclear. Our aim was to determine the efficacy of replacement therapy and the relationship between TSH concentration and QoL in patients diagnosed with primary hypothyroidism and receiving LT4 replacement therapy. Methods: This is a national retrospective cross-sectional study. Demographic information, a questionnaire for diagnosis and management of thyroid diseases and Thyroid related Patient Reported Outcome (ThyPRO) and EQ-5D questionnaires to assess quality of life were used to collect data. The study included retrospective 3 year follow up data. Results: Our study included 1750 patients (90.3% female, 9.7% male) from 26 centers with a mean age of 47.8 ± 12.6 years (18–88) and a body mass index of 28.84 ± 5.89 kg/m2. Patients had been receiving levothyroxine replacement for 10.23 ± 7.03 (3–55) years. The mean number of visits during the three-year follow-up period was 6.34 ± 2.78 [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21–22]. A total of 188 patients (10.7%) had never reached the specific TSH target. The target TSH value was reached < 3 times (n = 715; 40.8%), 3–5 times (n = 775; 44.2%), and ≥ 6 times (n = 260; 14.8%). According to the ThyPRO questionnaire, patients who achieved their treatment target fewer than 3 times had higher (worse thyroid related quality of life) scores in several domains, including goiter symptoms, hyper-/hypothyroid symptoms, fatigue, cognitive complaints, anxiety, depression, and impairments in social, sexual, and daily functioning. In contrast, these patients had lower EQ-5D scores, indicating poorer overall health-related quality of life. Conclusion: In hypothyroidism replacement therapy, it is crucial to establish an individualized TSH target, and the patient’s cognitive functions and quality of life are positively impacted by the attainment of euthyroidism.