title: Incidence, Clinical Course, and Risk Factors of Amiodarone-Induced Thyroid Dysfunction in Japanese Adults With Congenital Heart Disease.
abstract: BACKGROUND
  Although amiodarone (AMD)-induced thyroid dysfunction (AITD) is an important complication of AMD therapy, little is known about AITD in adult Japanese patients with congenital heart disease (CHD).
  
  
  RESULTS
  We retrospectively studied 131 adult patients with CHD who were on low-dose AMD (median, 150 mg/day). The median patient age was 28 years, and the median follow-up was 44 months. The incidence, clinical course, and risk factors of AITD, including AMD-induced thyrotoxicosis (AIT) and AMD-induced hypothyroidism (AIH), were evaluated. The total incidence of AITD was 30% (AIT: 18%, n=24; AIH: 12%, n=16). Approximately 67% of patients with AIT displayed deterioration of tachyarrhythmia, and 38% patients underwent steroid therapy. Although thyroid function and symptoms associated with AIT improved within 6 months after diagnosis in most patients with AIT (92%), 1 patient died suddenly during an acute phase of AIT. No patient with AIH exhibited deterioration of tachyarrhythmia, and 9 patients underwent thyroid hormone replacement therapy. Cox multivariate analysis identified no independent risk factor for AIT, whereas liver dysfunction (hazard ratio 2.573; 95% confidence interval 1.102-5.795) was an independent risk factor for AIH.
  
  
  CONCLUSIONS
  AITD commonly occurred in adult Japanese patients with CHD even though they were on a low-dose AMD regimen. Risk factors for AITD may vary according to ethnicity and diet.
authors.affiliation: Department of Pediatric Cardiology, Tokyo Women's Medical University.
authors.forename: Daiji
authors.initials: D
authors.lastname: Takeuchi
authors.forename: Kei
authors.initials: K
authors.lastname: Honda
authors.forename: Tokuko
authors.initials: T
authors.lastname: Shinohara
authors.forename: Kei
authors.initials: K
authors.lastname: Inai
authors.forename: Keiko
authors.initials: K
authors.lastname: Toyohara
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakanishi
mesh_terms: D000293:Adolescent; D000328:Adult; D000638:Amiodarone / Q000008:administration & dosage / Q000009:adverse effects*; D044466:Asian People; D005260:Female; D005500:Follow-Up Studies; D006330:Heart Defects, Congenital / Q000188:drug therapy* / Q000453:epidemiology; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced / Q000453:epidemiology; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013971:Thyrotoxicosis / Q000139:chemically induced / Q000453:epidemiology
chemical_list: D000638:Amiodarone