Thyroid Disease and Increased Cardiovascular Risk

Abstract

The effects of thyroid dysfunction are thought to be reversible on restoration of euthyroidism, but postmortem and epidemiologic data suggest that subclinical or treated thyroid disease is associated with increased vascular risk. In order to determine the extent of this risk, and to explore whether the nature and/or treatment of thyroid disease are critical in this relationship, we used medical record linkage to match patients with treated thyroid disease of various etiologies with routinely collected national inpatient and daycase hospital discharge records and death records, and assessed the number of hospitalizations from cardiovascular or cerebrovascular disease or death in patients with thyroid disease and control patients. Patients treated for Graves' disease had more hospitalizations from cardiovascular disease than controls (relative risk, 1.42; 95% confidence interval, 1.20 to 1.67; p < 0.001). Toxic multinodular goiter was also associated with significantly higher rates of cardiovascular disease (relative risk, 1.50; 95% confidence interval, 1.11 to 2.02; p = 0.008). Patients with Hashimoto's thyroiditis aged over 50 years had a threefold increase in cardiovascular admissions compared to controls (23.5% and 6.5%, respectively; 95% confidence interval for difference, 6.0% to 27.9%; p = 0.003). Thus, different forms of thyroid disease were associated with increased long-term vascular risk despite restoration of euthyroidism. The mechanisms that mediate this risk are unclear but may not involve thyroid hormone abnormality.

A critical review and meta-analysis of the association between overt hyperthyroidism and mortality

“…Refs, References. criteria (case-control or cohort studies) (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). Following review, studies were excluded because of an overlap with subjects from other studies (16,19,20); because reviews were not providing original data (12,13,22); due to inclusion of very few (n!10) hyperthyroid individuals to meaningfully allow calculation of the mortality risk (23,25); because of lack of overall mortality data (17); based on inclusion of a control group that was also hyperthyroid (30); or, finally, because evaluation of thyroid status was solely based on serum TSH (21) (Fig.…”

“…1). Details of the remaining eight (14,15,18,24,(26)(27)(28)(29) studies on which our review is based are shown in Table 1.…”

“…Seven of the eight studies are cohort studies (14,15,18,24,26,28,29) and one is a case-control study (27). In most studies, patients were ascertained from registers, where they have been either listed due to treatment with radioiodine (15,18,24,29) or based on treatment of hyperthyroidism at a hospital unit (14) or in primary care (26).…”

Medical Management of Hyperthyroidism

“…An increase in cardiovascular risk after RAI treatment has also been suggested. [12][13][14] However, Metso and colleagues found that hypothyroidism post-RAI offered protection from cardiovascular disease, suggesting that hyperthyroidism per se rather than RAI treatment is responsible for the increased cardiovascular events in these patients.…”

Association of single nucleotide polymorphism in CD28(C/T-I3 + 17) and CD40 (C/T-1) genes with the Graves disease

“…1 GD patients have normal thyroid hormone production and discharge but the physiological demands of body are not normal resulting in increased levels of thyroxin (T4) and tri-iodothyronine (T3) in blood. 2 This excessive T4 and T3 production results in goiter, palpitations and increased cardiovascular risk (classical symptoms of hyperthyroidism) 3 along with anxiety, heat intolerance, hand tremor, insomnia, hair loss, hyperactivity, excessive sweating, itching, weight loss regardless of increased appetite, frequent defecation, diarrhoea, muscle weakness, palpitations, and skin warmth and moistness in GD patients. 2,4 Certain risk factors including gender, age, stress, smoking, elevated concentrations of TSH, T3 and T4 in blood are known to affect the rate of GD.…”