The end of this paper includes these two statements:
Analysis of more than 3,000 participants aged 65 years or more without heart failure at baseline, who were followed up for 12 years in the Cardiovascular Health Study, showed that SCH participants who were treated with levothyroxine had a 72% reduction in heart failure events.
Despite known cardiovascular risks of SCH, there is not enough evidence for treating all patients at present due to current data being mostly based on observational studies or from small interventional trials with cardiac risk factor change as outcomes.
How many people have to suffer heart failure in order to provide the evidence that appropriate treatment of sub-clinical hypothyroidism is required?
Thyroid disease and vascular risk
Avais Jabbar, clinical research associate A and
Salman Razvi, consultant endocrinologist B⇑
+ Author Affiliations
A Newcastle University, Newcastle-upon-Tyne, UK
B Department of Endocrinology, Queen Elizabeth Hospital, Gateshead, UK, and honorary senior lecturer, Newcastle University, Newcastle-upon-Tyne, UK
Subclinical hypothyroidism (SCH) is a common condition seen in up to 10% of adults, mainly women and the elderly. Several prospective longitudinal cohort studies have shown a higher risk of cardiovascular disease in people with SCH but mainly in younger individuals. There are also a number of interventional trials that have shown that treatment of SCH with levo-thyroxine improves cardiovascular risk factors, but there is a dearth of level 1 evidence regarding cardiovascular events. In addition, there is increasing proof concerning the association of abnormal thyroid function at the time of an acute myocardial infarction with adverse cardiovascular outcomes. This review describes the literature dealing with thyroid function in relation to cardiovascular disease and also outlines the effect of treatment in addressing cardiovascular risk.