OBJECTIVES: Low-T3 syndrome is highly prevalent and independently prognostic in 
cardiovascular patients. The relationship and prognostic impact with the cardiac 
marker NT-pro-BNP have not been thoroughly investigated.
METHODS: Thyroid hormone levels and NT-pro-BNP were assessed in 615 consecutive 
patients hospitalized for cardiovascular disease. Patients with primary overt or 
latent thyroid disorder, hormone replacement, thyreostatic and amiodarone 
therapy were excluded. The association with and predictive impact on mortality 
were examined.
RESULTS: 36 (7.1%) patients had low-T3 syndrome. After adjustment for known 
confounders, NT-pro-BNP was significantly associated with fT3 and low-T3 
syndrome. fT3 (HR 0.58, 95%CI 0.34-0.98) and low-T3 syndrome (HR 3.0, 95%CI 
1.4-6.3) were predictive for mortality after adjustment for NT-pro-BNP levels 
and other cardiovascular prognostic variables. In patients with fT3 levels 
within the normal range, fT3 and NT-pro-BNP stratified by median values showed 
complementary prognostic information with the highest risk for mortality in 
patients with low normal fT3 and high NT-pro-BNP (HR 10.5, 95%CI 3.2-34.6).
CONCLUSIONS: fT3 and low-T3 syndrome are significantly related to NT-pro-BNP in 
patients with cardiovascular disease, but are predictors of mortality 
independently of NT-pro-BNP and other known cardiovascular risk parameters.