How frequently should a patient taking amiodarone be screened for thyroid dysfunction?

Area of Science:

• Cardiology
• Endocrinology
• Pharmacology

Background:

• Amiodarone therapy is associated with a high incidence of thyroid dysfunction.
• Current screening guidelines for amiodarone-induced thyroid dysfunction (AITD) lack consensus.
• Prevalence of AITD varies based on iodine intake and pre-existing thyroid conditions.

Purpose of the Study:

• To determine the incidence rate of AITD in patients on chronic amiodarone therapy.
• To identify optimal screening intervals for AITD.
• To evaluate risk factors associated with AITD development.

Main Methods:

• Prospective evaluation of 121 patients on chronic amiodarone.
• Follow-up of patients without AITD at baseline to assess incidence.
• Application of Cox proportional hazard model and sensitivity analysis for screening time identification.

Main Results:

• AITD was detected in 48.7% of patients (hypothyroidism in 41.3%, hyperthyroidism in 7.5%).
• Incidence rate of AITD was 62.8 per 1000 patient-years.
• The incidence rate of AITD during the first 6 months was 39.3 per 1000 patient-years.

Conclusions:

• AITD is a frequent complication of amiodarone treatment.
• Screening for AITD at 6-month intervals is supported by these findings.
• Further research is needed on the prognosis of untreated subclinical AITD.