Elaboration of a prognostic model associated with retinal hemorrhage in hemophagocytic lymphohistiocytosis

This retrospective case–control study focused on retinal hemorrhage associated with hemophagocytic lymphohistiocytosis (HLH), integrating various ocular examination parameters to investigate the survival and prognostic factors in HLH patients. Of 1973 assessed patients, 104 were finally recruited and 1:1 matched into retinal hemorrhage and control groups, with the hemorrhage area further graded in the former. Demographic and hematological data were collected; central, inner, outer retinal thickness and choroidal vascularity index (CVI) were measured via optical coherence tomography (OCT). Cox proportional hazards regression models (CoxPH) were elaborated, followed by bootstrapping internal validation and external validation. The hemorrhage group had significantly more intracranial lesions, lower hemoglobin, platelet count, and fibrinogen, and notably higher soluble interleukin-2 receptor (sIL-2R) and ferritin levels, along with significantly increased central inner retinal thickness,and reduced CVI. Ferritin and sIL-2R in the scattered hemorrhage group were significantly higher, and the survival time was significantly shorter than in the petechial hemorrhage group; scattered hemorrhage was predominant in moderate/high sIL-2R and ferritin subgroups. The CoxPH showed that retinal hemorrhage well predicted the survival and outcomes with a significantly higher hazard rate, and the model had high sensitivity, specificity, lower prediction error in external validation. This study elaborated a prognostic model in HLH, revealing that retinal hemorrhage is a hazard factor associated with increased severity and poorer prognosis in HLH patients.