Comparative prognostic value of high-sensitivity cardiac troponin T and NT-proBNP for 30-day mortality in non-cardiac critically ill patients

High-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are organ-specific biomarkers reflecting myocardial injury and cardiac biomechanical stress, respectively. Yet, neither is disease-specific, and both are frequently elevated in critically ill patients even in the absence of acute cardiac disease. This lack of specificity complicates their interpretation, and their relative prognostic importance remains uncertain. We retrospectively analyzed 827 adults admitted to ICU, excluding acute cardiac admissions and compared the prognostic utility of hs-cTnT and NT-proBNP measured at ICU admission for predicting 30-day mortality in non-cardiac critically ill patients. Non-survivors had higher hs-cTnT (67.2 vs. 37.7 ng/L; p < 0.001) and NT-proBNP (2340.5 vs. 1087.0 pg/mL; p < 0.001). In multivariable Cox models, only hs-cTnT remained independently predictive (highest vs. lowest hs-cTnT quartile: HR 1.44, 95% CI 1.05-1.96, p = 0.022). Adding hs-cTnT significantly improved the clinical base model (ΔLR χ²=14.6, p = 0.002; ΔAIC=-8.6), while NT-proBNP did not (ΔLRχ²=4.2, p = 0.240; ΔAIC = + 1.8). Including both biomarkers did not improve prediction beyond the model with hs-cTnT alone. In non-cardiac critically ill patients, hs-cTnT demonstrated independent and more consistent association with 30-day mortality than NT-proBNP. Myocardial injury, rather than cardiac biomechanical stress, may represent the more clinically relevant cardiac biomarker signal in this population.