Clinicopathological Prognostic Model for Survival in Adult Patients With Secondary Hemophagocytic Lymphohistiocytosis

ABSTRACT Background Data on bone marrow (BM) findings in secondary hemophagocytic lymphohistiocytosis (sHLH) and their association with overall survival (OS) are limited. Objectives This study aimed to develop a prognostic model incorporating BM findings and clinico‐laboratory factors affecting OS. Methods We retrospectively evaluated 50 adults with sHLH and developed a clinicopathological prognostic model based on survival‐associated factors. Results Most patients demonstrated normocellular BM (46.3%) and mild hemophagocytic activity (44.2%). Factors associated with survival in multivariable analyses (MVA) were age above 70 years (hazard ratio [HR] 3.89, p = 0.016), infection‐related (HR 4.62, p = 0.006), hemoglobin < 7 g/dL (HR 5.21, p < 0.001), and hypocellular marrow (HR 3.07, p = 0.04). A clinicopathological HLH risk model assigned 1 point to each MVA‐identified survival factor, categorizing patients into low‐ (score 0–1), intermediate‐ (score 2–3), and high‐risk (score 4) groups. The 6‐month OS from bootstrapping internal validation among the low‐, intermediate‐, and high‐risk groups were 84.2%, 55.6% ( p < 0.001) and 7.7% ( p < 0.001), respectively. The area under the receiver operating characteristic curve (AuROC) was 0.87. Conclusions This model stratified sHLH patients into three risk groups with distinct survival outcomes, potentially guiding future therapy.