Epidemiologic Trends in Patient and Hospital Characteristics of Nonalcoholic Steatohepatitis: A Longitudinal Study

Introduction: With growing prevalence of Nonalcoholic steatohepatitis (NASH) in general population, the complications of cirrhosis and co-morbid conditions, and rising awareness among the providers; the burden of NASH among hospitalized population is expected to rise. Our longitudinal study examines this trend along with patient and hospital characteristics of hospitalized patients with NASH. Methods: We used the National Inpatient Sample (NIS 2016-2020) and employed International Classification of Diseases-10th Edition (ICD-10) codes to identify all adult hospitalizations with NASH. The age and gender-adjusted linear trends were obtained using the Mantel-Haenszel linear trend test. Stata v4.2 was used to perform analyses. Changes in various demographics were assessed and the findings were also validated using National Readmission Database (NRD). Results: There were 539,274 hospitalizations among NASH adults from 2016 - 2020 (Table 1). The number of hospitalizations of NASH patients increased from 85,424 in 2016 to 121,910 in 2020 (P< 0.01). The rise was noted to be significantly higher among Black and Hispanic (P< 0.05) but not in white population. The mean age slightly increased from 61.2 to 62.7 years over the study period (P< 0.01). The longitudinal trend of NASH diagnosis was noted to be increasing in patients with Medicaid. while a decline was noted in those with private insurance. The comorbidity burden (marked by the Charlson comorbidity index) in NASH patients increased over the years. NASH-related hospitalization increased in small bed-size hospitals (from 15.3% in 2016 to 18.7% in 2020), while not changing in medium and large hospitals. NASH was noted proportionally more in teaching center hospitalizations while it showed a decreasing trend at non-teaching hospitals. Upon validation of these findings using NRD, we noted similar trends for all patient and hospital characteristics. Conclusion: Hospitalizations with NASH are rising in the US. This rise is noted among Black and Hispanic population. The inpatient NASH population is noted to be older and sicker overtime. NASH is reported more frequently during hospitalization in smaller hospitals, and in academic centers. While this could reflect general rise in NASH prevalence, but also could signify a growing awareness among healthcare providers about NASH. Healthcare costs resulting from these hospitalizations are expected to rise, as a rise among NASH inpatients with Medicaid is noted. Efforts to promote early detection and management of NASH are imperative, so that hospitalizations are minimized. Table 1. - Patient and Hospital Characteristic of Nonalcoholic Steatohepatitis Patients Variables Year 2016 2017 2018 2019 2020 P-value No. of hospitalization 85,424 96,400 110,840 124,700 121,910 < 0.01 Male 37.93 37.79 37.83 38.43 38.75 0.06 Female 62.07 62.21 62.17 61.57 61.25 0.12 Age, mean, y 61.22 61.59 62.04 62.47 62.26 < 0.01 Race, % White 78.48 77.01 76.44 76.53 75.50 0.32 Black 4.41 4.45 4.45 4.24 4.82 0.04 Hispanic 12.04 13.35 13.69 14.01 14.24 < 0.01 Others 5.07 5.19 5.43 5.22 5.44 0.24 Insurance type, % Medicare 57.01 57.62 58.69 59.33 57.86 0.09 Medicaid 12.17 12.63 12.11 12.15 13.44 < 0.01 Private 28.31 26.92 26.48 25.60 25.96 0.03 Uninsured 2.52 2.83 2.72 2.92 2.74 0.17 Household income quartile, % 1st 29.59 29.79 29.43 30.31 30.19 0.27 2nd 28.43 29.28 29.08 27.34 28.96 0.65 3rd 24.97 24.32 24.91 25.66 24.34 0.93 4th 17.01 16.62 16.58 16.70 16.51 0.72 Charlson comorbidity index score, %- 1 13.04 11.94 11.56 10.71 10.74 < 0.01 2 12.43 12.28 11.53 11.19 11.59 0.01 ≥ 3 74.53 75.78 76.91 78.10 77.67 < 0.01 Hospital size, % Small 15.35 17.11 17.05 18.64 18.72 < 0.01 Medium 25.36 25.22 26.23 24.75 25.66 0.97 Large 59.29 57.67 56.72 56.61 55.62 0.12 Hospital teaching status, % Rural nonteaching 7.99 7.65 7.38 7.52 8.13 0.91 Urban nonteaching 21.29 19.23 17.42 15.56 15.53 < 0.01 Urban teaching 70.72 73.13 75.21 76.92 76.34 < 0.01 Hospital region, % Northeast 15.24 15.45 15.68 15.32 15.56 0.93 Midwest 27.01 27.14 26.75 26.22 26.33 0.60 South 39.70 39.75 40.13 40.98 39.90 0.76 West 18.05 17.67 17.43 17.48 18.21 0.86 Bed-size: Small= < 200-250 beds, Large= >325-425 beds, Medium= < 325-425 beds but > than small hospitals. Note bed-size vary across regions in the USA, hence cutoffs for bed-size vary in different part.