Objective  To investigate the predictive value of D-dimer for in-hospital mortality and heart failure with reduced ejection fraction (HFrEF) in patients with acute myocardial infarction (AMI).

Methods A total of 688 patients with AMI who were hospitalized at Zhongshan Hospital, Fudan University, between January 2020 and December 2023 were retrospectively enrolled. Demographic and clinical characteristics, laboratory findings, echocardiographic parameters, and in-hospital outcomes were collected. The primary endpoints were in-hospital mortality and HFrEF. Multivariable logistic regression analysis was performed to assess the independent associations of D-dimer with in-hospital mortality and HFrEF. Receiver operating characteristic (ROC) curve analysis was used to evaluate its predictive performance.

Results With increasing D-dimer levels, age, inflammatory markers, peak troponin, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels progressively increased, whereas left ventricular ejection fraction progressively decreased. The incidence of HFrEF and in-hospital mortality differed significantly among the D-dimer groups (P＜0.05). Multivariable logistic regression analysis showed that elevated D-dimer was independently associated with an increased risk of in-hospital mortality in patients with AMI (OR=1.251, 95% CI 1.093–1.432, P=0.001), and was also independently associated with HFrEF (OR=1.075, 95% CI 1.028-1.124, P=0.002). ROC curve analysis showed that the area under the curve (AUC) of D-dimer for predicting in-hospital mortality was 0.871, while the AUC for predicting HFrEF was 0.716. At a cutoff value of 0.47 mg/L, the sensitivity and specificity of D-dimer in predicting HFrEF were 81.9% and 52.1%, respectively; at a cutoff value of 2.18 mg/L, the sensitivity and specificity of D-dimer in predicting in-hospital mortality were 63.6% and 93.8%, respectively. Restricted cubic spline analysis demonstrated significant non-linear associations between D-dimer and the risks of in-hospital mortality and HFrEF (P＜0.001).

Conclusions  Elevated D-dimer levels are significantly associated with increased risks of in-hospital mortality and HFrEF in patients with AMI and showed acceptable predictive performance. As a simple and readily available laboratory biomarker, D-dimer may provide useful information for early risk stratification and clinical management in patients with AMI.