Post-COVID-19 Thyroid Dysfunction and Autoimmune Ultrasound Changes: A 12-Month Prospective Cohort Study

Area of Science:

• Endocrinology
• Infectious Diseases
• Immunology

Background:

• Thyroid dysfunction is increasingly reported post-SARS-CoV-2 infection.
• Limited prospective longitudinal studies exist integrating biochemical and imaging assessments of thyroid health after COVID-19.

Purpose of the Study:

• To evaluate the 12-month evolution of thyroid function and structure after COVID-19 hospitalization.
• To identify the incidence of thyroiditis and changes in thyroid hormone levels and ultrasound findings.

Main Methods:

• Prospective cohort study of 71 patients hospitalized with COVID-19.
• Assessed thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), and thyroid antibodies at multiple time points.
• Performed color Doppler thyroid ultrasound at baseline and 6, 12 months.

Main Results:

• Subacute thyroiditis occurred in 6.0% of patients; newly detected autoimmune thyroiditis in 13.1% (excluding pre-existing conditions).
• Ultrasound patterns suggestive of autoimmune thyroiditis increased over time, even with minor biochemical changes.
• Thyroid hormone levels showed variability but mostly remained within reference ranges; associations with disease severity were weak.

Conclusions:

• A subset of patients experiences biochemical and structural thyroid changes up to 12 months post-COVID-19 hospitalization.
• Highlights the importance of targeted thyroid follow-up in specific patient groups after COVID-19.
• Suggests monitoring for persistent symptoms, borderline TSH, or ultrasound abnormalities indicative of autoimmune thyroiditis.