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Multiple visits are needed to achieve euthyroidism on levothyroxine in newly detected primary hypothyroidism. We aimed to develop a levothyroxine dose estimation algorithm for primary hypothyroidism. Adults with newly diagnosed hypothyroidism were enrolled prospectively, first in the training cohort, followed by the validation cohort separated by time and person. We developed a predictive algorithm from Training Cohort and validated the model in Validation Cohort. Training Cohort: In this cohort, 358 subjects (259 women and 99 men) were enrolled. The median duration needed to achieve euthyroidism was 4±0.5 months. The mean levothyroxine daily dose was 60.5±34.1 μg. Data of euthyroid subjects within 6 months of treatment initiation and age range 18–65 years were used for algorithm development. In the multivariable linear regression algorithm, pretreatment serum thyrotropin level, and sex formed the best-fit predictive model (adjusted R2 0.73, p-value <0.001). Validation Cohort: Eighty-four subjects (61 women and 23 men) were enrolled and started on an estimated levothyroxine dose derived from the developed prediction model. On the first follow-up on treatment, 34/50 participants achieved euthyroidism (68%) at 1.5 months. In conclusion, the proposed prediction model for levothyroxine dose estimation effectively achieves early euthyroidism in two-third subjects in the age range of 18–65 years. [ABSTRACT FROM AUTHOR]

Objectives: Many patients with hypothyroidism complain of persistent residual symptoms, despite optimal treatment, although the similar prevalence is seen in patients with documented absence of thyroid disorder in primary health-care setup. We aimed to investigate symptomatic relief in new cases of primary hypothyroidism and compare with controls with other chronic conditions. Methods: This prospective case-control follow-up study enrolled patients from July 2014 to May 2015 in an endocrine outpatient clinic of a tertiary hospital. Controls were age- and gender-matched ambulatory individuals with well-controlled other chronic diseases and no major comorbidity. Thyroid symptom questionnaire (TSQ) was administered at pretreatment to all the cases and then they were started on levothyroxine (LT). At euthyroidism, TSQ was readministered. For controls, TSQ was administered only once. TSQ was measured on Likert scale 1-4 for lack of energy, dry skin, constipation, aches and pains, cold intolerance, poor memory, depression, weight gain, tiredness after walking, and difficulty in getting up (DGU). P < 0.05 was considered statistically significant. Results: A total of 194 cases (147 females and 47 males) and 259 controls (187 females and 72 males) were analyzed. A significant difference in the symptoms prevalence was seen between controls and pretreatment cases, except for DGU, and between subclinical and overt hypothyroidism. Pretreatment serum thyroid-stimulating hormone in cases correlated significantly with all their pretreatment symptoms score. All symptoms prevalence decreased significantly posttreatment. At euthyroidism, the mean symptoms score in posttreatment cases was similar or lower than the controls. Conclusion: LT effectively improves the symptoms of hypothyroidism in newly diagnosed cases of primary hypothyroidism. The residual symptoms need an alternation explanation other than hypothyroidism. [ABSTRACT FROM AUTHOR]

We analyzed the relation of pretreatment anthropometric measures and serum thyrotropin (TSH) with the levothyroxine requirement. Children (3-18 years) brought to endocrine clinic with newly diagnosed acquired primary hypothyroidism were enrolled consecutively and prospectively with follow-up (July 2014 to April 2016). Children were started on levothyroxine, and dose was adjusted at regular intervals until achieved euthyroidism (serum TSH 0.4 to 4.5 mIU/L). The relationship of age, gender, height, weight, and serum TSH with levothyroxine dose was analyzed by univariate and multivariate regression analysis. Data of 51 children (42 girls and 9 boys) was used for the analysis. Age, weight, height, and serum TSH had significant correlation with levothyroxine daily dose based on weight (D/W) and dose based on BSA (D/BSA). Log10 TSH and gender explained ∼60% absolute levothyroxine daily requirement. The final model built with height and serum TSH predicted ∼85% of D/W and ∼80% of D/BSA.Conclusion: Pretreatment height and serum TSH can be used to determine levothyroxine dose needed to achieve euthyroidism in a newly diagnosed acquired primary hypothyroidism in children. What is Known: • The starting dose of levothyroxine is currently recommended based on the age of children. What is New: • In pediatric population, the effect of age on levothyroxine daily dose requirements can be explained by pretreatment height. • Pretreatment serum TSH level is an important predictor of levothyroxine daily dose in children with newly diagnosed primary hypothyroidism. [ABSTRACT FROM AUTHOR]

Objectives: The recommended starting dose of levothyroxine (LT4) in primary hypothyroidism is 1.6 μg/kg body weight and is based on presumption of minimal residual thyroid function in autoimmune hypothyroidism. This study aimed at finding the range and determining factors for LT4 dose in long-standing hypothyroidism. Methods: A cross-sectional study of individuals with primary autoimmune hypothyroidism on LT4 replacement was done between March 2015 and January 2016. Individuals enrolled were euthyroid based on recent serum thyroidstimulating hormone. The inclusion criteria included LT4 intake in the morning empty stomach, maintenance of at least 1-h food gap, not on medications known to hamper LT4 absorption within 4 h of dosing, diagnosis of hypothyroidism at least for 1 year, and on a minimum 25 μg LT4. P < 0.05 was considered statistically significant. Results: A total of 346 individuals (290 women and 56 men; 214 premenopausal and 76 postmenopausal women) were enrolled. The mean duration of hypothyroidism and age were 5.7 years and 42.1 years, respectively. The range and mean of absolute LT4 daily dose (ADD), LT4 dose based on body weight (D/W), and LT4 dose based on ideal body weight (D/IBW) were 25-200 μg daily and 77.1 μg, 0.3-2.82 μg/kg and 1.21 μg/kg, and 0.42-3.5 μg/kg and 1.58 μg/kg, respectively. Duration of hypothyroidism was significant predictors of ADD, D/W, and D/IBW. Gender-based difference in ADD and D/IBW was explained by gender difference in anthropometry. Conclusion: Long-standing primary autoimmune hypothyroidism has variable dose requirement of LT4 for achieving euthyroidism and may be dependent on the degree of residual functional thyroid. Duration of hypothyroidism was significant positive predictor for either ADD, D/W, or D/IBW. [ABSTRACT FROM AUTHOR]

Objective: Weight and age are traditionally used to decide levothyroxine (LT4) dose. The objective of study was to reanalyze the relationship of all the anthropometric measures and serum thyrotropin (TSH) with the LT4 requirement to achieve euthyroidism. Study Design: Study was prospective done at a single center (May 2014 to January 2016) in children brought to pediatric Endocrine clinic with newly diagnosed acquired primary hypothyroidism and being treatment naïve. Children were started on LT4, and dose adjusted at regular intervals to achieve normal range serum TSH (0.4 to 4.5 mIU/L). The relationship of age, gender, height, weight, body surface area (BSA), lean muscle mass (LBM) and baseline serum TSH with LT4 dose needed to achieve euthyroidism were assessed by multivariate regression analysis. Results: A total of 43 children (35 girls and 9 boys) completed the study. Mean LT4, LT4 based on weight (D/W), LT4 based on BSA (D/BSA) and LT4 based on LBM (D/LBM) were 68.75 ± 31.82 µg, 2.4 ± 1.6 µg/kg, 66.3 ± 38.7 µg/m2, and 2.8 ± 1.8 µg/ kg respectively. Age, weight, height, BSA, LBM, serum TSH and TSH_1 (values above 100 mIU/L were assigned 100 mIU/L) had significant correlation with D/W, D/BSA and D/LBM. TSH_1 and gender explained 73% of variability in LT4 requirement. Height and serum TSH constituted the best fit model in multivariate regression analysis. The model Adjusted R2 was 0.852, 0.837 and 0.857 for D/W, D/BSA and D/LBM respectively. Conclusion: Height and baseline serum TSH can be used to determine LT4 dose in newly diagnosed acquired hypothyroidism in children. [ABSTRACT FROM AUTHOR]