Background:

Low T3 syndrome is associated with elevated circulating levels of cytokines and interleukins, reinforcing the hypothesis of a close relation between the neuroendocrine system and certain inflammatory and immunological mechanisms involved in heart failure.

Objective:

To assess the progress of patients admitted for decompensated heart failure according to T3 levels on admission, and events during hospitalization and follow-up.

Materials and methods:

It was a prospective, observational, analytical study of 524 patients hospitalized for the first time with a diagnosis of decompensated heart failure. In-hospital and follow-up mortality and readmissions were evaluated according to normal or low T3 levels on admission. Ninety-one patients with known dysthyroidism, hypo or hyperthyroidism, previous thyroid surgery, sepsis or acute coronary syndrome were excluded. A subgroup analysis of patients receiving chronic amiodarone therapy was conducted, and prognostic variables were evaluated.

Results:

Of the 433 patients analyzed, 40.0% had low T3 (LT3) levels. Age, albumin level, age >75 years, and glomerular filtration rate (GFR) were independent predictors of LT3. While adaptation of guideline-recommended treatments increased in both groups, treatment rates in the LT3 group were significantly lower than those in the normal T3 (NT3) group (LT3 vs. NT3: Betablockers 81.5% vs. 89.4%, p=0.02; ACEI/ARA II 78.5% vs. 87.9%, p=0.001; anti-aldosterone agents 29.2% vs. 40.5%; p=0.019). Hospital mortality was higher in the LT3 group (5.8 vs. 1.5%), with no difference in rehospitalizations or mortality rates at follow-up. Of the subgroup of patients without amiodarone on admission (353), 37.8% had LT3. Patients in this subgroup were found to have significant differences in follow-up and in-hospital mortality (5.3% in LT3 vs. 0.9% in NT3, p=0.03, and 40.2% vs. 26.6%, p=0.023) respectively.

Conclusions:

Decompensated heart failure patients with LT3 on admission would represent a subgroup with more severe disease and worse prognosis during hospitalization.

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