Open AccessSubclinical hypothyroidism is an independent predictor of adverse cardiovascular outcomes in patients with acute decompensated heart failure
Author(s) -
Hayashi Tomohiro,
Hasegawa Takuya,
Kanzaki Hideaki,
Funada Akira,
Amaki Makoto,
Takahama Hiroyuki,
Ohara Takahiro,
Sugano Yasuo,
Yasuda Satoshi,
Ogawa Hisao,
Anzai Toshihisa
Publication year - 2016
Publication title -
esc heart failure
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.787
H-Index - 25
ISSN - 2055-5822
DOI - 10.1002/ehf2.12084
Subject(s) - subclinical infection , medicine , hazard ratio , heart failure , triiodothyronine , cardiology , acute decompensated heart failure , endocrinology , thyroid , adverse effect , gastroenterology , confidence interval
Aims Altered thyroid hormone metabolism characterized by a low triiodothyronine (T3), so‐called low‐T3 syndrome, is a common finding in patients with severe systemic diseases. Additionally, subclinical thyroid dysfunction, defined as abnormal thyroid stimulating hormone (TSH) and normal thyroxine (T4), causes left ventricular dysfunction. Our objective was to identify the prevalence and prognostic impact of low‐T3 syndrome and subclinical thyroid dysfunction in patients with acute decompensated heart failure (ADHF). Methods and results We examined 274 ADHF patients who were not receiving thyroid medication or amiodarone on admission (70 ± 15 years, 156 male), who underwent thyroid function tests. Euthyroidism was defined as TSH of 0.45 to 4.49 mIU/L; subclinical hypothyroidism as TSH of 4.5 to 19.9 mIU/L; and subclinical hyperthyroidism as TSH < 0.45 mIU/L, with normal free T4 level for the last two. Additionally, low‐T3 syndrome was defined as free T3 < 4.0 pmol/L among euthyroidism subjects. On admission, 188 patients (69%) showed euthyroidism, 58 (21%) subclinical hypothyroidism, 5 (2%) subclinical hyperthyroidism, and 95 (35%) low‐T3 syndrome. Cox proportional hazards models revealed that higher TSH, but not free T3 and free T4, was independently associated with composite cardiovascular events, including cardiac death and re‐hospitalization for heart failure. Indeed, subclinical hypothyroidism was an independent predictor (hazard ratio: 2.31; 95% confidence interval: 1.44 to 3.67; P < 0.001), whereas low‐T3 syndrome and subclinical hyperthyroidism were not. Conclusions Subclinical hypothyroidism on admission was an independent predictor of adverse cardiovascular outcomes in ADHF patients, suggesting a possible interaction between thyroid dysfunction and the pathophysiology of ADHF.