ObjectiveEmerging evidence suggests a potential role for soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cardiovascular pathophysiology. However, plasma sTREM2 levels in patients with acute decompensated heart failure and their possible association with adverse clinical outcomes have not been fully characterized.MethodsIn this retrospective cohort study, we enrolled patients with acute decompensated heart failure between 2020 and 2023 and defined a composite endpoint comprising all-cause mortality and heart failure-related readmission. Baseline plasma sTREM2 levels were compared across clinical categories and acute decompensated heart failure phenotypes using appropriate statistical tests. The prognostic value of sTREM2 was evaluated using Kaplan-Meier survival curves, restricted cubic splines, and Cox proportional hazards regression models. Model calibration was validated using bootstrap-corrected plots with 1000 resamples. Furthermore, time-dependent receiver operating characteristic curves, net reclassification improvement, and integrated discrimination improvement were used to assess the incremental predictive value of sTREM2 over N-terminal pro-B-type natriuretic peptide. Finally, subgroup analyses were performed to assess the robustness of the findings.ResultsA total of 128 patients (median age, 75.5 years) were enrolled, with 58 (45.3%) reaching the composite endpoint during follow-up. Plasma sTREM2 levels were significantly higher in patients with acute decompensated heart failure than in healthy controls (P < 0.001) and showed a progressive increase with worsening New York Heart Association functional class. Multivariable Cox regression analysis demonstrated that each 50 pg/mL increment in sTREM2 was independently associated with an increased risk of the composite endpoint (adjusted hazard ratio: 1.594; 95% confidence interval: 1.170-2.173) and heart failure-related readmission (adjusted hazard ratio: 1.802; 95% confidence interval: 1.310-2.480). Restricted cubic spline analysis confirmed a linear association between sTREM2 levels and clinical outcomes (all P for nonlinear > 0.05). Although adding sTREM2 to N-terminal pro-B-type natriuretic peptide did not significantly increase the area under the curve, it provided incremental predictive value for heart failure-related readmission. Subgroup analyses revealed no significant interactions (all P for interaction > 0.05).ConclusionOur findings demonstrate that sTREM2 is a potential biomarker in acute decompensated heart failure. Elevated sTREM2 levels are independently associated with an increased risk of adverse clinical outcomes, particularly heart failure-related readmission, underscoring its potential utility in risk stratification and clinical management of acute decompensated heart failure.