Endothelial activation and stress index (EASIX) score is a stronger predictor of survival after allogeneic hematopoietic stem cell transplantation than acute-phase biomarkers.

[BACKGROUND AIMS] Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for hematologic malignancies, but it is associated with a risk of treatment-related mortality. The endothelial activation and stress index (EASIX) has emerged as a prognostic biomarker in allo-HSCT, with high scores linked to reduced overall survival (OS) and increased non-relapse mortality (NRM). EASIX reflects endothelial dysfunction, microangiopathic stress and end-organ injury.

[METHODS] This retrospective, population-based single-center study included 159 consecutive patients receiving allo-HSCT at a tertiary hospital in Norway from 2006 to 2021, the majority of whom received myeloablative conditioning. We compared the prognostic impact of the EASIX score and biomarkers of inflammation/acute-phase reaction.

[RESULTS] The EASIX score showed only weak correlations with acute-phase biomarkers and no significant correlation with postconditioning fluid retention. High EASIX was associated with reduced OS in the Kaplan-Maier analysis, and patients with high EASIX in addition showed an increased risk of NRM. Contrary, acute-phase biomarkers did not show significant associations with OS or NRM in our cohort. Patients with high EASIX scores were also characterized by older age, slightly increased preconditional C-reactive protein and an increased frequency of other diagnoses than acute leukemia.

[CONCLUSIONS] EASIX was associated with decreased OS driven by increased NRM, supporting its role as a marker of endothelial dysfunction and stress, with limited association to inflammation.