
Berenice Pena Aparicio
Instituto Nacional de Cardiología Ignacio Chávez, MexicoTitle: Association of Antithyroid Antibodies with the Development of Manifest Hypothyrodism in Subjects with Subclinical Hypothyroidism
Abstract
Background: Subclinical
Hypothyroidism (SCH) is defined as the increase in serum levels of TSH >4.0
mu/l with normal values of free thyroxine (T4L 0.8 - 1.7 ng/dl). SCH has a
prevalence of 0.7 to 16% and a progression to manifest hypothyroidism (MH) of 2
to 6% per year. Hashimoto thyroiditis is the main cause of SCH and is
characterized by the presence of thyroid anti peroxidase antibodies (TPOAB).
This study aimed to determine the association of TPOAB with the development of
MH in mexican subjects with SCH and to evaluate the frequency of SCH
persistence, evolution of MH, and regression to euthyroidism (EU) in these
subjects.
Methods: Basal
concentrations of TPOAB, TSH, and T4L were determined in serum samples of
subjects with SCH followed for 6.2 years. Prevalence of SCH, EU, and MH was
defined after follow-up. Multivariate logistic regression analysis was used to
evaluate the association of TPOAB with the development of MH and the OR was
calculated (95% CI).
Results: 226 subjects were
included, average age of 55.1 ± 8.5 years, 65% women. The frequency of TPOAB in
the whole population was of 22.6%. After 6.2 years of follow-up, 68 subjects
(30.1%) reverted to EU, 56 (24.8%) evolved to MH, 102 (45.1%) remained with SCH. Compared with the subjects that reverted to EU
and with those remaining in SCH, subjects with MH had a higher TPOAB (17.6%,
18.6%, and 35.7%, respectively; p = 0.025). The prevalence of TPOAB, tabaquism,
age and gender were considered for the multivariate analysis. Results: the
presence of TPOAB confers a 2.8-times higher risk (95% CI: 1.24-6.56) for the
development of MH.
Conclusion: A positive and
independent association of TPOAB with the development of MH was found. Mexican
subjects with SCH and TPOAB have 2.8-times higher risk to develop MH after 6.2
years.
Biography
Berenice Pena
has completed her Specialty in Clinical Endocrinology and Master's in Medical
Sciences with Honorable Mention at the National Autonomous University of Mexico
(UNAM). She is assigned and Coordinator of the Endocrinology Clinic, External
Consultation of the Ignacio Chávez National Institute of Cardiology, Mexico
City. Full Professor in Human Resources Training in Undergraduate and
Postgraduate courses at UNAM. He actively carries out Clinical Research in the
Cardiometabolic Area, in addition to being Professor in Chief of Academic
Events of Continuous Medical Update at a National and International level.