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Subclinical hyperthyroidism and the risk of coronary heart disease and mortality

Tinh-Hai Collet1, Jacobijn Gussekloo, Douglas C Bauer

  • 1Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland.

Archives of Internal Medicine
|April 25, 2012
PubMed

Insights

Subclinical hyperthyroidism significantly increases risks for total mortality, coronary heart disease (CHD) mortality, and atrial fibrillation (AF). These risks are highest with lower thyrotropin levels, underscoring the importance of thyroid monitoring.

Area of Science:

  • Endocrinology
  • Cardiology
  • Epidemiology

Background:

  • Conflicting data exists on the cardiovascular risks associated with subclinical hyperthyroidism.
  • Large prospective cohort studies are needed to clarify these associations.

Purpose of the Study:

  • To assess the risks of total mortality, coronary heart disease (CHD) mortality, CHD events, and atrial fibrillation (AF) in individuals with endogenous subclinical hyperthyroidism.
  • To analyze these risks across large, pooled prospective cohorts.

Main Methods:

  • Individual participant data from 10 prospective cohorts (52,674 participants) were pooled.
  • Defined subclinical hyperthyroidism as thyrotropin < 0.45 mIU/L with normal free thyroxine, excluding medication users.
  • Analyzed CHD events (22,437 participants) and incident AF (8,711 participants).

Main Results:

  • Subclinical hyperthyroidism (4.2% of participants) was linked to increased total mortality (HR 1.24), CHD mortality (HR 1.29), and AF (HR 1.68).
  • Risks for CHD mortality and AF were significantly higher with thyrotropin levels < 0.10 mIU/L.
  • Attributable risks ranged from 14.5% for total mortality to 41.5% for AF.

Conclusions:

  • Endogenous subclinical hyperthyroidism is associated with elevated risks of total mortality, CHD mortality, and incident AF.
  • The highest risks for CHD mortality and AF occur when thyrotropin levels are below 0.10 mIU/L.
  • These findings highlight the cardiovascular implications of subclinical hyperthyroidism.
Abstract

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