S2126 Risk-Adjusted Outcomes and Clinical and Demographic Predictors of Inpatient Mortality in Patients With and Without Spontaneous Bacterial Peritonitis: A Nationwide Analysis From the 2022 NIS

Introduction: Spontaneous bacterial peritonitis (SBP) is a severe and potentially fatal complication of cirrhosis, associated with substantial morbidity and mortality. While previous studies have shown a declining trend in SBP-related inpatient mortality, updated national data are needed to assess current outcomes and identify patient-level predictors of death. Methods: We conducted a retrospective cohort study using the 2022 NIS database. Hospitalizations involving adults (≥18 years) with SBP were identified using International Classification of Diseases, Tenth RevisionClinical Modification code K65.2. A comparator group of 8,000 adult hospitalizations without SBP was randomly sampled and frequency-matched by age and race, resulting in a final cohort of 16,082 patients. The primary outcome was inpatient mortality. Secondary outcomes included identifying independent predictors of mortality using multivariable logistic regression, adjusting for age, sex, race, insurance status, comorbidities, and All Patient Refined Diagnosis Related Groups (APR-DRG) risk of mortality and severity scores. Results: Among 6.5 million hospitalizations, 8,082 SBP cases were identified (0.12%). SBP patients had significantly higher inpatient mortality than non-SBP patients (16.7% vs 2.5%, P < .001) and remained an independent predictor of death (odds ratio = 4.49). Other predictors included acute kidney injury, coagulopathy, hepatic encephalopathy, and complicated hypertension. Vitamin D deficiency was inversely associated with mortality. Although diabetes and obesity were more prevalent in SBP patients, they were not independently linked to death. Racial disparities persisted, with Black, Asian, and Other/Unknown race patients having higher mortality, while Hispanic patients had lower odds. Insurance and gender were not significant predictors. Conclusion: SBP remains a significant cause of inpatient mortality. Using 2022 NIS data, we found a 16.7% mortality rate in SBP patients, much higher than in non-SBP cases. SBP was an independent predictor of death, along with acute kidney injury, coagulopathy, hepatic encephalopathy, and complicated hypertension. While diabetes and obesity were more common in SBP patients, they were not independently linked to mortality. Racial disparities persisted, with higher mortality among Black and Asian patients. Vitamin D deficiency was unexpectedly associated with lower mortality, warranting further study. These findings highlight the need for risk-based interventions and equitable cirrhosis care.