Impact of Triiodothyronine and N-Terminal Pro-B-Type Natriuretic Peptide on the Long-Term Survival of Critically Ill Patients With Acute Heart Failure

We assessed the prognostic implications of low triiodothyronine (T3) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in critically ill patients with acute heart failure. We acquired data for 144 critical care patients with acute decompensated heart failure, of which 106 were included in this study. Plasma thyroid hormones and NT-proBNP levels were determined within 48 hours of admission. We assessed these measures for predicting all-cause and cardiac mortalities. At a mean follow-up period of 25 ± 31 months, the all-cause mortality rate was 51% (54 of 106) and the cardiac mortality rate was 70% (38 of 54). A multivariate Cox regression model showed that log-transformed NT-proBNP levels (log NT-proBNP; hazard ratio [HR] 2.90, 95% confidence interval [CI] 1.38 to 6.08, p = 0.005) and T3 levels (HR 0.98, 95% CI 0.96 to 0.99, p = 0.008) were associated with all-cause mortality, and log NT-proBNP (HR 3.70, 95% CI 1.28 to 10.71, p = 0.02) and T3 (HR 0.98, 95% CI 0.96 to 0.99, p = 0.01) were associated with cardiac mortality. Based on cut-off values for NT-proBNP (10,685 pg/ml) and T3 (52.3 ng/dl), Kaplan-Meier analyses provided significant prognostic information with the highest risk for all-cause mortality in the low T3 (≤52.3 ng/dl)/high NT-proBNP (>10,685 pg/ml) group (HR 8.54, 95% CI 4.19 to 17.40, p <0.0001). In conclusion, T3 levels appear to be independent predictors for both all-cause and cardiac mortalities among critical ill patients with heart failure, and high NT-proBNP and low T3 levels predict a worse long-term outcome.