S2851 Analyzing the Trends in Admissions Related to Autoimmune Hepatitis and the Growing Burden on Healthcare: A Decade-Long National Study From the USA

Introduction: Although some studies have suggested a rise in the incidence of autoimmune hepatitis (AIH), data regarding hospitalization trends and healthcare burden is sparse. In this retrospective study, we aimed to describe the trends in AIH among all-cause admissions in the United States over a decade and their growing healthcare burden. Methods: We analyzed the 2012-2021 NIS. The presence of autoimmune hepatitis was identified using International Classification of Diseases, Ninth and Tenth Revision (ICD-9/10) codes “K754”. We estimated the year-by-year trends in hospitalizations of AIH relative to all-cause admissions, stratified by sex, age, and race, using Cochran–Armitage tests. The inflation-adjusted total hospital costs (USD) were also compared over the 10 years. A logistic regression model estimated how age, sex, race, and year impacted the odds of having a higher than median cost of hospitalization. Results: From 2012 to 2021, AIH-related hospitalizations increased from 55.2 cases per 100,000 admissions to 80.1 per 100,000 (Ptrend < 0.01). Similar overall rising trends were noted based on sex, race, and age groups. Total costs rose from 290.5 million in 2012 to 477.2 million in 2021 (Ptrend < 0.01). Overall increments in cost were also observed in our stratified groups (Ptrend < 0.01 throughout). A multivariable regression model showed that the odds of reporting a hospital cost higher than median were higher among patients ages 46-59 years (aOR 1.317, 95% CI 1.283-1.352, P < 0.01) and ages ≥60 years (aOR 1.407, 95% CI 1.376-1.439, P < 0.01) (vs Ages 18-45). Racial disparities were also seen as Blacks (aOR 1.173, 95% CI 1.143-1.204, P < 0.01), Hispanics (aOR 1.346, 95% CI 1.311-1.382, P < 0.01), and Asian Americans/Pacific-Islanders (AAPI) (aOR 1.827, 95% CI 1.724-1.937, P < 0.01) tended to be more likely to report higher than median costs than Whites. The burden also followed an annual pattern (aOR 1.045, 95% CI 1.041-1.048, P < 0.01). AIH admissions was higher among women than men, they were less likely to report a hospital cost higher than the overall median (aOR 0.880, 95% CI 0.861-0.900, P < 0.01). Conclusion: This study confirmed that AIH is a growing healthcare concern and burden. In addition, racial, sex-based, and age-based discrepancies in hospital costs were found. This calls for additional studies to first identify at-risk groups for AIH and provide adequate screening and follow-ups to mitigate the risks of severe hospitalizations.