Hemophagocytic Syndromes in Adults: Real-World Data on Mortality from a Tertiary Reference Center

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by excessive immune activation, cytokine storm, and aberrant macrophage function. Although HLH is well studied in children, data on adult HLH remain limited. Our primary goal was to examine in-hospital mortality and its associated risk factors in patients with HLH in a tertiary center.

This retrospective study at University Hospital Bern queried the hospital database using the i2b2 system to analyze adult HLH patients, assessing clinical, laboratory data, treatments, and outcomes according to the HLH-2004 criteria and Saint-Antoine score.

From 845,846 patients seen in the hospital between 2014 and 2021, a cohort of 54 adult HLH patients was identified. The overall mortality rate was 40.7%. In univariate analysis, we found that deceased patients with HLH were significantly older than surviving patients (median age of 69.6 [range 22-83] vs. 52.5 [24-79] years old [p = 0.002]). Patients with HLH were significantly more likely to have cardiopulmonary and neurological complications, higher alkaline phosphatase levels, lower platelet counts, need platelet transfusions, and lower response rate to the HLH therapy. In multivariate analysis, age (HR 0.94; 95% CI 0.89-0.99; p = 0.024), cardiopulmonary (HR 7.045; 95% CI 1.28-38.66, p = 0.025), neurologic complications (HR 5.55; 95% CI 1.01-30.51; p = 0.04), and the requirement of platelet transfusions (HR 6.22; 95% CI 1.16-33.20; p = 0.032) were all independently associated with in-hospital mortality.

This study identifies risk factors whose early presence can be used to stratify management strategies and improve prognosis in patients with HLH.