Published in:
01-11-2018 | Original Contributions
The Effect of the Bariatric Surgery Type on the Levothyroxine Dose of Morbidly Obese Hypothyroid Patients
Authors:
Jorge Pedro, Filipe Cunha, Pedro Souteiro, João Sérgio Neves, Vanessa Guerreiro, Daniela Magalhães, Rita Bettencourt-Silva, Sofia Castro Oliveira, Maria Manuel Costa, Joana Queirós, Paula Freitas, Ana Varela, Davide Carvalho
Published in:
Obesity Surgery
|
Issue 11/2018
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Abstract
Background
Doubts exist about the effect of different bariatric surgery (BS) types on levothyroxine (Lt4) absorption. We compared Lt4 doses and their variation (ΔLt4) in patients with hypothyroidism that underwent malabsorptive (MS) or restrictive (RS) surgery and studied predictors of Lt4 dose change.
Methods
Retrospective study of morbidly obese hypothyroid patients submitted to BS. We compared RS (“sleeve” gastrectomy or adjustable gastric banding) with MS (Roux-en-Y gastric bypass) patients. We built a multivariable logistic regression and a linear regression model to study predictors of Lt4 dose changes and ΔLt4, respectively.
Results
Fifty-seven patients: 35 MS and 22 RS. Mean age 47 years; 7% men. Patients submitted to MS had lower BMI at 1 year than those submitted to RS. Lt4 dose remained unchanged in 61.4%, increased in 12.3%, and decreased in 26.3% of patients. Initial and 1-year Lt4 dose were not different between surgical groups. Relative Lt4 dose, but not absolute (p = 0.07), increased at 1 year (p < 0.001). Neither BS nor BMI variation were predictors of Lt4 dose variation. BMI variation was associated with relative Lt4 dose change independently of initial BMI and BS type: β (95%CI) − 0.03 (− 0.05; 0.00); p = 0.03.
Conclusions
There were no differences in Lt4 dose and its variation between restrictive and malabsorptive techniques 1 year after surgery. Malabsorptive procedures may not affect Lt4 absorption differently from restrictive ones. Bariatric surgery type was not predictive of Lt4 dose changes. BMI variation is associated with relative Lt4 dose (dose per weight) variation and its association was independent of bariatric surgery type.