Factors Affecting Levothyroxine Dose in Primary Hypothyroidism

الملخص

Primary hypothyroidism is a deficiency of thyroid hormone due to diseases affecting the thyroid gland itself. Our objective was to determine whether age, gender, ideal body weight, and menstrual status affect levothyroxine dose in primary hypothyroidism to achieve euthyroidism. The study was performed retrospectively by reviewing the charts of patients being treated for primary hypothyroidism in the endocrinology clinic in Benghazi Diabetes Center, who had TSH values within a normal range. The selected patients were taking LT4 without any confounding medications and had no serious chronic conditions.  All the subjects of primary hypothyroidism on maintenance dose for at least 12 months were considered. The total number of subjects with primary hypothyroidism was 539; only 100 subjects were eligible for the study. Subjects included both men & women between the ages of 24 & 88 years who have primary hypothyroidism. TSH parameters across study groups ANOVA test (P=0.058, no significant difference). Weight-based LT4 dose parameters across study groups. The difference is not statistically significant between men, premenopausal women, and menopausal women. Dot plot for the relationship between age, weight, and mean LT4 weight-based dose (statistically not significant relationship). Dot plot for the relationship between mean TSH level and mean LT4 weight-based dose (statistically not significant relationship). The LT4 dose is not primarily driven by a patient’s Age, gender, or menstrual status, but it is by body weight. This knowledge may eventually improve the ability to predict a patient’s dose requirement and thus more quickly attain a euthyroid status when initiating LT4 therapy.