From the Guidelines
Patients with type 1 diabetes should be tested for antithyroid peroxidase and antithyroglobulin antibodies soon after diagnosis, and thyroid-stimulating hormone concentrations should be measured at diagnosis when clinically stable or soon after glycemic control has been established, as recommended by the most recent guidelines 1. When considering the management of thyroid function in patients with type 1 diabetes, it is essential to prioritize the detection of autoimmune thyroid disease, which is the most common autoimmune disorder associated with diabetes, occurring in 17–30% of individuals with type 1 diabetes 1.
Key Recommendations
- Testing for antithyroid peroxidase and antithyroglobulin antibodies should be performed soon after the diagnosis of type 1 diabetes, as the presence of these antibodies is predictive of thyroid dysfunction, most commonly hypothyroidism 1.
- Thyroid function tests may be misleading if performed at the time of diagnosis due to the effect of previous hyperglycemia, ketosis, or ketoacidosis, and should be repeated soon after a period of metabolic stability and achievement of glycemic targets 1.
- Subclinical hypothyroidism may be associated with an increased risk of symptomatic hypoglycemia and a reduced linear growth rate, highlighting the importance of early detection and management 1.
Management Considerations
- For patients with elevated TPO antibodies but normal thyroid function tests, monitoring of thyroid function every 6-12 months is recommended, as these individuals have an increased risk of developing hypothyroidism in the future 1.
- Treatment of thyroid dysfunction typically involves thyroid hormone replacement therapy (levothyroxine) at doses individualized to the patient's needs, and is essential for managing the condition and preventing long-term complications 1.
From the Research
Thyroid Peroxidase Overview
- Thyroid peroxidase (TPO) is an enzyme that plays a crucial role in the production of thyroid hormones 2.
- TPO antibodies are a type of autoantibody that can be present in individuals with autoimmune thyroid disease 3.
Relationship between TPO Antibodies and Thyroid Function
- Studies have shown that there is a correlation between TPO antibody levels and thyroid function test parameters, such as T3, T4, and TSH 2.
- Individuals with high TPO antibody levels are more likely to have abnormal thyroid function 4.
Determinants of TPO Antibody Levels
- Female sex and current smoking have been identified as determinants of TPO antibody positivity 3.
- Higher age and alcohol consumption are associated with lower odds of TPO antibody detectability 3.
Clinical Implications of TPO Antibodies
- TPO antibody detectability is associated with a higher risk of overall, cancer-related, and cardiovascular mortality 3.
- The presence of TPO antibodies can be used as a marker for autoimmune thyroid disease and may be useful in guiding early therapeutic interventions 5.
TPO Antibodies as Inflammatory Markers
- TPO antibodies and high-sensitivity C-reactive protein (hsCRP) have been identified as potential markers of thyroid autoimmunity and systemic inflammation 5.
- Individuals with subclinical hypothyroidism and positive TPO antibodies tend to have higher levels of hsCRP, indicating a systemic inflammatory state 5.