From the Guidelines
Thyroid peroxidase antibody titers are not recommended for routine measurement in patients with subclinical hypothyroidism, as their presence or absence does not change the diagnosis or expected efficacy of treatment. The presence of anti-TPO antibodies can identify an autoimmune etiology for thyroid dysfunction and predict a higher risk of developing overt hypothyroidism, with a risk of 4.3% per year compared to 2.6% per year in antibody-negative individuals 1. However, this information does not alter the management of subclinical hypothyroidism, which is based on serum TSH measurements. Some key points to consider include:
- The presence of anti-TPO antibodies indicates an autoimmune cause of thyroid dysfunction
- Elevated antibody levels are associated with a higher risk of progressing to overt hypothyroidism
- The diagnosis and treatment of subclinical hypothyroidism are based on serum TSH measurements, not antibody levels 1
- Routine measurement of anti-TPO antibodies is not recommended due to insufficient evidence supporting its clinical utility in this context 1.
From the Research
Thyroid Peroxide Antibody Titre Relevance
- The presence of anti-thyroid peroxidase (TPO) antibodies is a significant factor in the progression of subclinical hypothyroidism to overt hypothyroidism 2, 3.
- Patients with subclinical hypothyroidism and positive TPO antibodies have a higher risk of developing overt hypothyroidism compared to those without antibodies 3, 4.
- The presence of TPO antibodies is also associated with an increased risk of heart failure, coronary artery disease events, and mortality from coronary heart disease 3.
- However, the clinical utility of TPO antibodies in determining treatment outcomes is unclear, and some studies suggest that positive anti-TPO antibodies are not associated with better quality of life or improvement in clinical outcomes with levothyroxine treatment 5.
- Elevated TPOAb levels have been associated with a lower mortality risk in the oldest old, but are not associated with changes in thyroid function, physical function, disability in activities of daily living, cognitive function, or depressive symptoms 6.
Treatment Considerations
- Treatment with levothyroxine is recommended for patients with subclinical hypothyroidism and positive TPO antibodies, especially in pregnant women and women contemplating pregnancy 2.
- However, the rationale for treatment in non-pregnant adults with subclinical hypothyroidism and serum TSH values ≤10 mIU/L is controversial, and treatment should be considered on a case-by-case basis 2, 3.
- In older adults with subclinical hypothyroidism, positive anti-TPO antibodies are not associated with more benefits on clinical outcomes with levothyroxine treatment 5.