Predictors of TSH Normalization in Thyrotoxicosis Patients after Treatment

Purpose: Thyrotoxicosis, characterized by elevated thyroid hormone levels, is a significant public health concern. This study aimed to identify predictive factors for the delayed thyroid function recovery in thyrotoxicosis patients, a crucial aspect for optimizing treatment and patient care. Methods We retrospectively reviewed the medical records of adult thyrotoxicosis patients diagnosed at Kaohsiung Veterans General Hospital, Taiwan, from January 2014 to December 2021. The study assessed patient characteristics, comorbidities, medications, and laboratory data. The main outcome was the rate of thyroid stimulating hormone (TSH) normalization, defined as achieving normalized levels within 3 months. Results The study included 443 patients, with a mean age of 47.2 years and a predominance of female patients (73.1%). The average time to achieve normalized TSH levels was 6.9 months. Key factors associated with delayed TSH normalization included higher body mass index (BMI) [odds ratio (OR) = 1.06, confidence interval (CI): 1.01–1.12], elevated serum free T4 levels (OR = 1.97; CI, 1.44–2.69), and treatment with propylthiouracil (OR = 2.66; CI, 1.33–5.32). In contrast, factors such as sex, age, season of diagnosis, and comorbidities did not significantly impact the rate of TSH normalization. Conclusion The study highlights the importance of considering individual patient characteristics, such as BMI and initial free T4 levels, in thyrotoxicosis management. The findings suggest a potential preference for carbimazole over PTU in achieving faster TSH normalization. This research contributes to the understanding of thyrotoxicosis recovery and supports the need for personalized treatment approaches in clinical practice.