Low plasma triiodothyronine levels in heart failure are associated with a reduced anabolic state and membrane damage

Abstract

BackgroundLow plasma triiodothyronine (T3) levels are considered a prognostic predictor of death in heart failure (HF) patients.AimTo study an association between plasma T3 levels and several cardiac, neurohormonal, and metabolic markers of HF.MethodsA total of 133 ambulatory HF patients (114 males; mean age 63.2 years) with left ventricular ejection fraction <40% were enrolled. TSH, total tetraiodothyronine (T4) and T3, N-terminal pro-brain natriuretic peptide (NT-proBNP), and other cardiac and metabolic parameters were measured. The lowest tertile of T3 (group 1) was compared against the two upper ones (group 2).ResultsIn simple logistic regression, the lowest T3 tertile was associated with more advanced HF disease status: older (age: odds ratio (OR)=1.05; confidence interval (CI) 95% 1.01–1.09, P=0.004), lower functional capacity (walking test: OR=0.996; CI 95% 0.993–0.999, P=0.008), higher NT-proBNP (OR=1.64; CI 95% 1.19–2.27, P=0.003) and adiponectin levels (OR=1.07; CI 95% 1.02–1.11, P=0.004), lower DHEAS log-transformed (OR=0.50; CI 95% 0.31–0.80, P=0.004), and the presence of lower phase angle values as measured by body bioelectrical impedance analysis (OR=3.18; CI 95% 1.50–6.71, P=0.04) and worse renal function (OR=0.96; CI 95% 0.94–0.98, P=0.003). T3 levels in the lowest tertile were independently associated with low phase angle values (OR=2.95, CI 95% 1.16–7.50, P=0.02) and the log transformation of DHEAS (OR=0.56; CI 95% 0.32–0.97, P=0.04).ConclusionWe have demonstrated an association between plasma T3 levels in the lower range and other deranged hormonal and metabolic parameters in HF patients.