Supplementary Material for: Cardiac troponin T and NT-proBNP for prediction of 30-day readmission or death in patients with acute dyspnea: Data from the Akershus Cardiac Examination 2 Study

Introduction: N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) measurements are recommended in patients with acute dyspnea. We aimed to assess the prognostic merit of cTnT compared to NT-proBNP for 30-day readmission or death in patients hospitalized with acute dyspnea. Methods: We measured cTnT and NT-proBNP within 24 hours in 314 patients hospitalized with acute dyspnea and adjudicated the cause of the index admission. Time to first event of readmission or death ≤30 days after hospital discharge was recorded and cTnT and NT-proBNP measurements were compared head-to-head. Results: Five patients died during the index admission and were excluded from the study. Patients who died (7/309) or were readmitted (71/309) within 30 days had higher cTnT concentrations (median 29.1, Q1-Q3 18.2-73.9 ng/L) compared to patient who survived and were not readmitted (median 19.4, Q1-Q3 8.4-36.1 ng/L; p <0.001). There were no statistically significant differences in NT proBNP concentrations when stratifying patients according to readmission or death within 30 days: median 1540.6, Q1-Q3 424-5571 ng/L vs. median 984, Q1-Q3 201-3600 (p = 0.07). cTnT concentrations separated patients with poor and favorable outcomes, both for the total cohort and for patients with adjudicated heart failure (HF). cTnT concentrations were associated with readmission or death within 30 days after discharge, both in the total cohort (adjusted hazard ratio [aHR] 1.65, 95% CI 1.30-2.08) and in patients with HF (aHR 1.60, 95% CI 1.15-2.24). In contrast, NT-proBNP concentrations were not associated with prognosis in the total cohort (aHR 1.11, 95% CI 0.94-1.31) or in patients with adjudicated HF (aHR 1.03, 95% CI 0.78-1.37). In the subgroup analysis of HF patients, where patients with acute HF were grouped according to LVEF (HFpEF and HFrEF), cTnT and NT proBNP did not predict short-term outcomes for HFrEF, but cTnT predicted short-term outcomes in HFpEF patients. Conclusions: cTnT concentrations associate with post-discharge 30-day readmission or death in patients hospitalized with acute dyspnea, as well as in in patients adjudicated HF. The association of cTnT with outcomes in HF appears driven by strong associations of cTnT in patients with HFpEF.