The main finding of our study is that ALD including AH is the most common etiology in AI/AN individuals compared to other races and ethnicities among cirrhosis-related admissions in the US. A total of 6% admissions result in in-hospital mortality, which is increased in blacks compared to AI/AN, and is similar to admissions in non-black races or ethnicities.
Several previous studies have shown that AI/AN individuals have high prevalence of cirrhosis compared to other races. [7, 8] For example, mortality from any cause between 1999 and 2009 in AI/AN located in contract health services delivery area counties was 46% greater than among non-Hispanic whites. Further, ALD was the leading cause of cirrhosis related mortality for AI/AN as well as non-Hispanic whites. Moreover, healthcare burden from ALD is increasing among individuals aged 25–44 years, a population at the prime of productivity and contribution to the national growth. [2, 5, 7, 8, 16] Our study on hospitalized patients with cirrhosis including subgroups of decompensated cirrhosis or those with ACLF showed a novel finding that admissions in AI/AN individuals were more likely to have diagnosis of ALD including AH.
Higher prevalence of AUD in AI/AN as observed in this and earlier studies may likely explain this finding. AUD is known to be associated with geographic location, socioeconomic status, and education of the individual. Higher prevalence in this study was observed in AI/AN individuals after controlling for these potential confounders. Patients with ALD compared to other liver diseases are known to often present at an advances stage of cirrhosis and/or complications. Several factors including gender, alcohol use patterns (binge use, drinking outside meals, type of alcohol, and severity of AUD), socioeconomic status, having insurance, receipt of treatment for risk factor of AUD, and specialty care for liver disease determine receipt of treatment of any liver disease including ALD.[19, 20] Further, genetic polymorphisms of alcohol metabolizing enzymes may predispose an individual to AUD, and polymorphisms of PNPLA3, TMSF62, and MBOAT7 genes have been shown to predispose an individual with AUD to development of and severity of ALD. Although, we were able to account for socioeconomic and insurance status, lack of availability of data on other clinical variables in the NIS database and blood samples for genetic analyses limited assessment on association of other variables with predisposition of AUD and ALD in AI/AN individuals.
About 6% of admissions with discharge diagnosis of cirrhosis were associated with in-hospital mortality. These data are similar to in-hospital mortality observed in other studies using the NIS database on admissions with cirrhosis. The in-hospital mortality was higher in blacks compared to AI/AN, but similar to other races. In another study using the death certificate data (1999–2016) from the Center for Disease Control, the overall mortality was projected to increase by 10.1% between 2017 and 2030 for AI/AN and for white men, contributing to 239,700 excess deaths. In the same study, mortality from chronic liver disease/cirrhosis was projected to increase for all races, except black men, similar to what we observed in the current study. Other factors such as genetic polymorphisms, obesity and other comorbidities are known to modify disease progression in ALD.
Large sample size using the national US database on a homogeneous population of admissions with cirrhosis is a potential strength of our study. Further, using a cohort of AI/AN individuals matched for other races and analysis controlled for some of the potential confounders like geographic location, socioeconomic status, and insurance payer is another strength. However, a cautious approach is suggested on the interpretation of our observations as the authors recognize few limitations of this study. For example, potential coding error in adjudicating the discharge diagnosis as the study population was identified using the ICD codes. Further, admissions were not linkable to patient identifier, which limited evaluation of readmissions. Unavailability of laboratory values during the hospitalization and post-discharge follow up data, and lack of data from Veteran hospitals are some other limitations of this study.
In summary, this study on hospitalized patients with cirrhosis in the US shows that ALD and/or AH is the most common cirrhosis etiology in AI/AN individuals compared to other races. The in-hospital mortality among cirrhosis related hospitalizations is increased in blacks compared to AI/AN, while this is similar to non-black race. Large multicenter studies are needed to examine other factors such as alcohol use patterns, receipt and type of provider care for AUD and for liver disease, genetic polymorphisms to further study mechanisms of our findings. Further, these studies would also provide useful data to derive public health policies like prevention or treatment of AUD, early detection of silent advanced fibrosis, and increased access to healthcare, and reduce ALD related healthcare burden, especially in AI/AN.