Epidemiology and Outcomes of Hepatic Veno-Occlusive Disease after Allogeneic Hematopoietic Stem Cell Transplantation: A Descriptive Analysis of the U.S. National Inpatient Sample.

INTRODUCTION Hepatic veno-occlusive disease (HVOD), or sinusoidal obstruction syndrome (SOS), is a potentially liefe-threatening complication following allogeneic stem cell transplantation (allo-SCT). Historically, HVOD has affected up to 60% of allo-SCT recipients, with reported mortality rates exceeding 75% in severe cases. The approval of defibrotide in 2016 represented a major therapeutic milestone, significantly improving outcomes in high-risk patients. Despite this advancement, large-scale data on HVOD epidemiology & outcomes in allo-SCT recipients remain limited. This study aims to address these gaps & offer updated insights into its clinical impact.

METHODS We utilized National Inpatient Sample (2016-2020) to examine factors associated with HVOD in allo-SCT recipients. Admissions for allo-SCT & HVOD were identified using International Classification of Diseases, Tenth Revision. Baseline characteristics, including patient demographics, hospital characteristics, comorbidities, complications & outcomes were compared between allo-SCT admissions with & without HVOD. Categorical variables were analyzed by χ² test (%), & continuous variables by adjusted Wald's test (mean±SD).

RESULTS During the study period, 200 allo-SCT admissions with HVOD were identified. HVOD admissions were younger (45.05 vs. 52.42 years; P=0.0045) & were more likely to be female (43.72% vs. 25%; P=0.0191). They had higher rates of acute graft-versus-host disease (GVHD) (17.5% vs. 6.47%; P=0.0043), acute respiratory failure (32.5% vs. 8.37%; P<0.001), & acute kidney injury (50% vs. 20.66%; P<0.001). Hepatic complications, including portal hypertension (7.5% vs. 0.52%; P<0.001), hepatic encephalopathy (12.5% vs. 0.28%; P<0.001), cirrhosis (7.5% vs. 0.07%; P<0.001), ascites (37.5% vs. 1.97%; P<0.001) & spontaneous bacterial peritonitis (2.5% vs. 0.06%; P<0.001) were also more common in this cohort. HVOD was associated with worse outcomes, including longer hospital stays (45.5 vs. 29.51 days; P<0.001) & over 6 times higher in-hospital mortality (30% vs. 4.72%; P<0.001). HVOD also imposed a greater economic burden, with more than double mean total hospitalization charges ($1,321,650 vs. $541,391.1; P<0.001) & nearly triple hospitalization costs ($358,463.2 vs. $141,464.1; P<0.001).

CONCLUSION This study describes HVOD-specific characteristics in allo-SCT admissions. Patients with HVOD were younger, had higher comorbidity burden, & showed increased rates of acute GVHD, multiorgan dysfunction, & hepatic complications. They also faced high in-hospital mortality, longer hospital stays, & greater healthcare costs.