Thyroid Dysfunction and Cardiovascular Events in Patients With Dysglycemia
Reema Shah1, Steven Orlov1, Guillaume Paré1
1Population Health Research Institute, Hamilton Health Sciences, Hamilton, Ontario, Canada; McMaster University, Hamilton, Ontario, Canada.
Canadian Journal of Diabetes
|March 1, 2023
Summary
Subclinical hypothyroidism increases cardiovascular event and mortality risk in high-risk individuals with dysglycemia. Levothyroxine use was associated with fewer deaths in this population.
Area of Science:
- Endocrinology
- Cardiology
- Public Health
Background:
- Subclinical thyroid disease is a common endocrine dysfunction.
- Thyroid dysfunction is linked to adverse cardiovascular outcomes, particularly in high-risk individuals.
- Individuals with dysglycemia and cardiovascular risk factors are a key population for study.
Purpose of the Study:
- To assess the association between thyroid function and thyroid hormone replacement therapy with cardiovascular outcomes.
- To evaluate cardiovascular outcomes in high-risk individuals with dysglycemia and thyroid dysfunction.
- To determine the impact of subclinical hypothyroidism and levothyroxine use on cardiovascular events and mortality.
Main Methods:
- Analysis of 8,401 participants from the ORIGIN trial with baseline thyrotropin (TSH) measurements.
- Assessment of composite cardiovascular outcomes, including myocardial infarction, stroke, heart failure, and cardiovascular death.
- Estimation of hazard ratios for outcomes based on baseline TSH levels (euthyroid, subclinical hypothyroidism, overt hypothyroidism) and levothyroxine use, with adjustments for clinical characteristics.
Main Results:
- Subclinical hypothyroidism (5.5% of participants) was associated with an increased risk of an expanded cardiovascular outcome (HR=1.24) and mortality (HR=1.37).
- Overt hypothyroidism was present in 2.2% of participants.
- Levothyroxine use was linked to a reduction in deaths (HR=0.72).
Conclusions:
- Subclinical hypothyroidism is a predictor of future cardiovascular events and mortality in individuals with dysglycemia and cardiovascular risk factors.
- Thyroid hormone replacement therapy (levothyroxine) may offer a survival benefit in this population.
- These findings highlight the importance of thyroid function assessment in cardiovascular risk stratification.
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