@article {1053, title = {Subclinical thyroid dysfunction, cardiac function, and the risk of heart failure. The Cardiovascular Health study.}, journal = {J Am Coll Cardiol}, volume = {52}, year = {2008}, month = {2008 Sep 30}, pages = {1152-9}, abstract = {

OBJECTIVES: The goal of this study was to determine whether subclinical thyroid dysfunction was associated with incident heart failure (HF) and echocardiogram abnormalities.

BACKGROUND: Subclinical hypothyroidism and hyperthyroidism have been associated with cardiac dysfunction. However, long-term data on the risk of HF are limited.

METHODS: We studied 3,044 adults>or=65 years of age who initially were free of HF in the Cardiovascular Health Study. We compared adjudicated HF events over a mean 12-year follow-up and changes in cardiac function over the course of 5 years among euthyroid participants, those with subclinical hypothyroidism (subdivided by thyroid-stimulating hormone [TSH] levels: 4.5 to 9.9, >or=10.0 mU/l), and those with subclinical hyperthyroidism.

RESULTS: Over the course of 12 years, 736 participants developed HF events. Participants with TSH>or=10.0 mU/l had a greater incidence of HF compared with euthyroid participants (41.7 vs. 22.9 per 1,000 person years, p=0.01; adjusted hazard ratio: 1.88; 95\% confidence interval: 1.05 to 3.34). Baseline peak E velocity, which is an echocardiographic measurement of diastolic function associated with incident HF in the CHS cohort, was greater in those patients with TSH>or=10.0 mU/l compared with euthyroid participants (0.80 m/s vs. 0.72 m/s, p=0.002). Over the course of 5 years, left ventricular mass increased among those with TSH>or=10.0 mU/l, but other echocardiographic measurements were unchanged. Those patients with TSH 4.5 to 9.9 mU/l or with subclinical hyperthyroidism had no increase in risk of HF.

CONCLUSIONS: Compared with euthyroid older adults, those adults with TSH>or=10.0 mU/l have a moderately increased risk of HF and alterations in cardiac function but not older adults with TSH<10.0 mU/l. Clinical trials should assess whether the risk of HF might be ameliorated by thyroxine replacement in individuals with TSH>or=10.0 mU/l.

}, keywords = {Aged, Aged, 80 and over, Cohort Studies, Echocardiography, Female, Heart, Heart Failure, Heart Function Tests, Humans, Hyperthyroidism, Hypertrophy, Left Ventricular, Hypothyroidism, Male, Risk Factors, Time Factors}, issn = {1558-3597}, doi = {10.1016/j.jacc.2008.07.009}, author = {Rodondi, Nicolas and Bauer, Douglas C and Cappola, Anne R and Cornuz, Jacques and Robbins, John and Fried, Linda P and Ladenson, Paul W and Vittinghoff, Eric and Gottdiener, John S and Newman, Anne B} }