Objective: Levothyroxine (LT4) is used by almost 13 million patients in USA and in the same country it has been estimated that 35% of subjects are obese. Oral thyroxine has a narrow therapeutic index and the dose must be tailored on the patient to avoid the over- or under-treatment and the related side effects. Studies on this subject were mostly carried out in thyroidectomized patients and/or in non standardized treatment schedule. Our study was aimed at investigating LT4 daily requirement in overweight or obese patients taking T4 in a tightly controlled fashion. Methods: Upon the exclusion of patients non-compliant and/or using drugs and/or with diagnosed gastrointestinal disorders, 60 overweight/obese hypothyroid patients with Hashimoto’s thyroiditis (55 F/5 M; median age = 44 ys) represented the study group. They were subdivided in: 26 overweight (O), 17 class I obese (C-I), 10 class II obese (C-II), 7 class III obese (C-III). Thirtyfive (34 F/1 M; median age = 40 ys) age-matched patients with normal BMI (<25 kg/m2), treated in the very same way, represented the reference group (RG). All those patients were treated with oral T4 under fasting conditions and abstaining from eating or drinking for at least one hour after treatment. Once stably attained the desired serum TSH (median TSH: RG = 1.16 mU/l; O = 1.24 mU/l; C I-III = 1.46 mU/l; p = ns), daily T4 requirement was compared in each subgroup. Results: Normal and overweight patients showed an identical LT4 requirement (1.27 μg/Kg/day) to attain similar median TSH value. In contrast, a significantly reduced need for T4 (–17%; p < 0.0001) was observed in obese as compared to both normal- and over-weight patients. T4 requirement inversely correlated with BMI ranging from 1.12 μg/Kg/day (BMI < 35 kg/ m2; n = 17) to 1.00 μg/Kg/day; (BMI >35 kg/m2; n = 17) (–12%; p = 0.023). Conclusion: Daily T4 requirement is similar in normal and overweight patients while all classes of obese patients show a progressively reduced need for T4 requirement.
THYROXINE TREATMENT IN OVERWEIGHT AND OBESE HYPOTHYROID PATIENTS / Virili, Camilla; Capriello, Silvia; Santaguida, MARIA GIULIA; Cellini, Miriam; Brusca, Nunzia; Gargano, Lucilla; Centanni, Marco. - STAMPA. - (2016). (Intervento presentato al convegno 39th Annual Meeting of the European Thyroid Association tenutosi a Copenhagen).
THYROXINE TREATMENT IN OVERWEIGHT AND OBESE HYPOTHYROID PATIENTS
Camilla Virili
;Silvia Capriello
;Maria Giulia Santaguida
;Miriam Cellini
;Nunzia Brusca
;Marco Centanni
2016
Abstract
Objective: Levothyroxine (LT4) is used by almost 13 million patients in USA and in the same country it has been estimated that 35% of subjects are obese. Oral thyroxine has a narrow therapeutic index and the dose must be tailored on the patient to avoid the over- or under-treatment and the related side effects. Studies on this subject were mostly carried out in thyroidectomized patients and/or in non standardized treatment schedule. Our study was aimed at investigating LT4 daily requirement in overweight or obese patients taking T4 in a tightly controlled fashion. Methods: Upon the exclusion of patients non-compliant and/or using drugs and/or with diagnosed gastrointestinal disorders, 60 overweight/obese hypothyroid patients with Hashimoto’s thyroiditis (55 F/5 M; median age = 44 ys) represented the study group. They were subdivided in: 26 overweight (O), 17 class I obese (C-I), 10 class II obese (C-II), 7 class III obese (C-III). Thirtyfive (34 F/1 M; median age = 40 ys) age-matched patients with normal BMI (<25 kg/m2), treated in the very same way, represented the reference group (RG). All those patients were treated with oral T4 under fasting conditions and abstaining from eating or drinking for at least one hour after treatment. Once stably attained the desired serum TSH (median TSH: RG = 1.16 mU/l; O = 1.24 mU/l; C I-III = 1.46 mU/l; p = ns), daily T4 requirement was compared in each subgroup. Results: Normal and overweight patients showed an identical LT4 requirement (1.27 μg/Kg/day) to attain similar median TSH value. In contrast, a significantly reduced need for T4 (–17%; p < 0.0001) was observed in obese as compared to both normal- and over-weight patients. T4 requirement inversely correlated with BMI ranging from 1.12 μg/Kg/day (BMI < 35 kg/ m2; n = 17) to 1.00 μg/Kg/day; (BMI >35 kg/m2; n = 17) (–12%; p = 0.023). Conclusion: Daily T4 requirement is similar in normal and overweight patients while all classes of obese patients show a progressively reduced need for T4 requirement.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
