Subclinical Atrial Fibrillation: How Large is the Risk of New Onset Atrial Fibrillation?

586 460 adult family practice patients without previously recorded thyroid disease or atrial fibrillation had their thyroid function evaluated for the first time by their family practitioner. 562 461 (96.0 %) were euthyroid, 1670 (0.3 %) had overt hypothyroidism, 12 087 (2.0 %) had subclinical hypothyroidism, 3966 (0.7 %) had overt hyperthyroidism, and 6276 (1.0 %) had subclinical hyperthyroidism. Compared with the euthyroid individuals, the risk of atrial fibrillation was closely associated with thyroid activity, with a low risk in overt hypothyroidism, high risk in hyperthyroidism, and a TSH level dependent association with risk of atrial fibrillation across the spectrum of subclinical thyroid disease.

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(State: 11.09.2013)