Aims: Sinusoidal obstruction syndrome (SOS) is a life-threatening complication of hematopoietic stem cell transplantation (HSCT) associated with significant morbidity and mortality. Healthcare utilization, costs, and mortality were assessed in HSCT patients diagnosed with SOS, with and without multi-organ dysfunction (MOD).
Materials and methods: This retrospective observational study identified real-world patients undergoing HSCT between January 1, 2009 and May 31, 2014 using the Premier Healthcare Database. In absence of a formal ICD-9-CM diagnostic code, SOS patients were identified using a pre-specified definition adapted from Baltimore and Seattle criteria and clinical practice. Severe SOS (SOS/MOD) and non-severe SOS (SOS/no-MOD) were classified according to clinical evidence for MOD in the database.
Results: Of the 5,418 patients with a discharge diagnosis of HSCT, 291 had SOS, with 134 categorized as SOS/MOD and 157 as SOS/no-MOD. The remaining 5,127 patients had HSCT without SOS. Overall SOS incidence was 5.4%, with 46% having evidence of MOD. Distribution of age, gender, and race were similar between the SOS cohorts and non-SOS patients. After controlling for hospital profile and admission characteristics, demographics, and clinical characteristics, the adjusted mean LOS was 31.0 days in SOS/MOD compared to 23.9 days in the non-SOS cohort (medians = 26.9 days vs 20.8 days, p < .001). The adjusted mean cost of SOS/MOD patients was $140,653, which was $41,702 higher than the non-SOS cohort (medians = $105,749 vs $74,395, p < .001). An almost 6-fold increased odds of inpatient mortality was associated with SOS/MOD compared to the non-SOS cohort (odds ratio = 5.88; 95% CI = 3.45-10.33).
Limitations: Limitations of retrospective observational studies apply, since the study was not randomized. Definition for SOS was based on ICD-9 diagnosis codes from a hospital administrative database and reliant on completeness and accuracy of coding.
Conclusions: Analysis of real-world data shows that SOS/MOD is associated with significant increases in healthcare utilization, costs, and inpatient mortality.
Keywords: 30-day readmissions; Burden of illness; Costs; Healthcare resource utilization; Hematopoietic stem cell transplantation (HSCT); Hepatic veno-occlusive disease (VOD); Hospital length of stay; Inpatient mortality; Multi-organ dysfunction; Sinusoidal obstruction syndrome (SOS).