ODP598 Liquid levothyroxine (L-T4) maintains more stable TSH levels in hypothyroid patients, than tablet L-T4

Abstract

Abstract Hypothyroidism affects approximately 5% of the population, mostly women and people over 60 years of age. The standard therapy used for the treatment of hypothyroidism is tablet levothyroxine (L-T4). Thyroid-stimulating hormone (TSH) is monitored, and L-T4 is adjusted as necessary to reach euthyroidism. Upon the stabilization of TSH levels in the normal range, it is recommended to perform an annual testing in treated patients to warrant suitable replacement. Large population studies showed an increased mortality in people with TSH in the hypothyroid range, demonstrating the importance of maintaining a stable TSH level in the normal range. We evaluated the stability of circulating TSH in hypothyroid patients treated with liquid L-T4, with respect to those treated with tablet L-T4. We enrolled patients with normal circulating TSH levels at the basal evaluation, not reporting any malabsorption or drug interference issues, who were in treatment with liquid or tablet L-T4.Six hundred and fifty six hypothyroid patients treated with liquid L-T4 were compared to 328 hypothyroid subjects receiving tablet L-T4 (both groups were matched by age and gender).Patients were followed for two years, and serum TSH, FT3, FT4 levels were assessed after one and two years. At the first abnormal TSH value, the evaluated parameters were: age, gender, body mass index, history of chronic autoimmune thyroiditis, initial TSH, and L-T4 dosage. At the time of initial normal TSH, these parameters were not associated significantly with time to abnormal TSH values. After 1 year, normal TSH values were registered in 86% of the patients who received L-T4 liquid formulation, but only in 81% of patients treated with tablet L-T4. After 2 years, normal TSH values were registered in 84% of patients receiving L-T4 liquid formulation, while only in 74% of those with tablet L-T4 (p<0.05). To sum up, the obtained data suggest that liquid L-T4 maintains more efficiently (than tablet L-T4) normal TSH levels in hypothyroid patients in the long term follow-up. Presentation: No date and time listed