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. 2023 Sep 18;108(10):e956-e962.
doi: 10.1210/clinem/dgad250.

Iodine-Induced Hyperthyroidism and Long-term Risks of Incident Atrial Fibrillation and Flutter

Kosuke Inoue  1 , Rong Guo  2   3 , Martin L Lee  4   5 , Ramin Ebrahimi  6   7 , Natalia V Neverova  6   7 , Jesse W Currier  6   7 , Muhammad T Bashir  2 , Angela M Leung  8   9
Affiliations

Iodine-Induced Hyperthyroidism and Long-term Risks of Incident Atrial Fibrillation and Flutter

Kosuke Inoue et al. J Clin Endocrinol Metab. .

Abstract

Context: Although iodine-induced hyperthyroidism is a potential consequence of iodinated radiologic contrast administration, its association with long-term cardiovascular outcomes has not been previously studied.

Objective: To investigate the relationships between hyperthyroidism observed after iodine contrast administration and incident atrial fibrillation/flutter.

Methods: Retrospective cohort study of the U.S. Veterans Health Administration (1998-2021) of patients age ≥18 years with a normal baseline serum thyrotropin (TSH) concentration, subsequent TSH <1 year, and receipt of iodine contrast <60 days before the subsequent TSH. Cox proportional hazards regression was employed to ascertain the adjusted hazard ratio (HR) with 95% CI of incident atrial fibrillation/flutter following iodine-induced hyperthyroidism, compared with iodine-induced euthyroidism.

Results: Iodine-induced hyperthyroidism was observed in 2500 (5.6%) of 44 607 Veterans (mean ± SD age, 60.9 ± 14.1 years; 88% men) and atrial fibrillation/flutter in 10.4% over a median follow-up of 3.7 years (interquartile range 1.9-7.4). Adjusted for sociodemographic and cardiovascular risk factors, iodine-induced hyperthyroidism was associated with an increased risk of atrial fibrillation/flutter compared with those who remained euthyroid after iodine exposure (adjusted HR 1.19, 95% CI 1.06-1.33). Females were at greater risk for incident atrial fibrillation/flutter than males (females, HR 1.81, 95% CI 1.12-2.92; males, HR 1.15, 95% CI 1.03-1.30; P for interaction = .04).

Conclusion: Hyperthyroidism following a high iodine load was associated with an increased risk of incident atrial fibrillation/flutter, particularly among females. The observed sex-based differences should be confirmed in a more sex-diverse study sample, and the cost-benefit analysis of long-term monitoring for cardiac arrhythmias following iodine-induced hyperthyroidism should be evaluated.

Keywords: arrhythmia; atrial fibrillation; hyperthyroidism; iodine; thyroid dysfunction.

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Figures

Figure 1.
Figure 1.
Flow chart of study sample selection.
Figure 2.
Figure 2.
Cumulative incidence of atrial fibrillation according to thyroid function (euthyroid vs hyperthyroid) following iodine exposure.
Figure 3.
Figure 3.
Associations between hyperthyroidism and risk of atrial fibrillation by age, sex, and race/ethnicity.
See this image and copyright information in PMC

References

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