Trends of Costs and Admission Rates Among Patients Admitted With Autoimmune Hepatitis: Analysis of US Hospitals Using the NIS Database

Background and aim: Autoimmune hepatitis (AIH) is a prominent cause of chronic liver disease in the United States. This study aims to characterize the incidence, mortality, and cost implications of this condition using a national database. Method: The 2016-2019 National Inpatient Sample was used to select patients with AIH. After adjusting for inflation, weighted charge data were used to calculate the admission costs using chargeto-cost ratios. Demographic, socioeconomic status, and comorbidity values were used to build strata to characterize admission incidence, mortality data and aggregate and per-capita cost values. Furthermore, additional sensitivity analysis was performed using a stratified set of patients with AIH as one of the top 10 diagnosis (AIH-specific subsample). Multinomial regression curves were graphed and assessed to derive goodness-of-fit for each trend. R2 and P-values were calculated. Results: From 2016 to 2019, the total admissions related to AIH were approximately 20,984, 21,905, 22,055, and 22,680 cases, respectively (R2: 0.93, Pvalue: 0.03). AIH-related hospitalization aggregate costs came to $338.18, $369.17, $355.98, and $387.25 million dollars (R2: 0.75, P-value: 0.17). Significant admission growth was seen in the Southern region (R2: 0.91, P-value: 0.05). Most notably, increasing trends in total admissions were found across older age, those of White and Hispanic descent, and those with comorbidities. On the other hand, the AIH-specific subsample illustrated decreasing trends in admissions across demographics (i.e., age, gender, and race) and comorbidities; however, those with hepatic complications saw a rise in the admission trends (cirrhosis - R2: 0.98, Pvalue: 0.009; multiple liver complications - R2: 0.95, P-value: 0.03). Conclusion: Among AIH-specific admissions, there was a decreasing trend overall; however, there was an exceptional increase in the admissions among those with hepatic complications. ( J CLIN EXP HEPATOL 2024;14:101279)