Replacement Dose of Levothyroxine and Its Influencing Factors in Adults with Primary Hypothyroidism in Chongqing, China

In order to know the daily physiological replacement dose of levothyroxine sodium (L-T4) and its possible influencing factors in adults with primary hypothyroidism in Chongqing, China.A cross-sectional survey, including gender, age, height, weight, and body mass index, fat free mass (FFM), body surface area (BSA), cause of hypothyroidism, whether menopause or not (female), Chalson comorbidity index scores(CCI score), long-term oral L-T4 dose and so on, was conducted among 517 patients with hypothyroidism in Chongqing,China.The multivariate linear stepwise regression analysis model was used to investigate the correlation between these factors and the L-T4 replacement dose. The optimal scale regression model was used to understand the effect of each relevant factor on the L-T4 replacement dose.The daily physiological replacement dose of L-T4 in patients with primary hypothyroidism was 72.0±22.6μg, which was approximately equal to 1.27±0.40μg / kg / day. 34.2% of the L-T4 doses can be affected by Age, BMI, causes of hypothyroidism, and CCI scores.The effect of hyperthyroidism 131I treatment and CCI score ≥4 on L-T4 dose was statistically significant. The degree of influence of each factor was as follows: age (55.6%), BMI (15.2%), cause of hypothyroidism (14.7%), and CCI score (14.6%).The daily physiological replacement dose of L-T4 in chinese patients with primary hypothyroidism in chongqing was 72.0±22.6μg, which was approximately equal to 1.27±0.40μg / kg / day. The causes of hypothyroidism, age, BMI, and other diseases have affected the L-T4 replacement dose in some degrees, which has certain guiding significance for long-term replacement therapy for patients with clinical hypothyroidism.