SAT-425 Characteristics of Hypothyroid Patients Achieving Long Term Euthyroidism on Levothyroxine Treatment

• Published in: Journal of the Endocrine Society 2020-05, Vol.4 (Supplement_1)
• Main Authors: Tandeter, Howard, Murad, JaYanah, Alfandari, Liad, Novack, Victor, Fraenkel, Merav
• Format: Article
• Language: English
• Subjects: Thyroid
• ISSN: 2472-1972; 2472-1972
• DOI: 10.1210/jendso/bvaa046.946

Background Studies have shown that hypothyroid patients treated with Levothyroxine replacement therapy often experience fluctuations in TSH levels, while others remain well controlled over time. Aim To assess the association between pre-treatment TSH and other biochemical and clinical characteristics and long-term maintenance of normal TSH under Levothyroxine treatment. Methods This is a retrospective nested case-control study. Study population included patients above age 18 insured by Clalit Health Service (CHS) in the South of Israel between the years 2002-2017, diagnosed with hypothyroidism (ICD 9 code 244.9) and who had at least one TSH measurement before initiating levothyroxine therapy, purchased this medication for at least 5 consecutive years with one annual TSH measurement while on treatment. Patients with surgical, post iodine ablation or congenital hypothyroidism were excluded. Patients with a TSH level within the normal range for 5 consecutive years were defined as cases while the others served as controls. Demographic, laboratory, pregnancy status and pharmacy purchase were extracted from the computerized medical records of CHS and compared between the groups. Results Out of 5472 patients included in the study, 644 had a normal TSH for 5 consecutive years (11.8%, cases). Mean age at first levothyroxine purchase was 55.8±13.7 in cases and 54.10±16.2 in controls (p=0.003) and females comprised 84.8% and 81.4% respectively (p=0.035). Mean pretreatment TSH was 5.15±9.6 in cases and 10.02±29 in controls (p