Non-invasive markers of inflammation in alcohol-associated liver disease: A scoping review

Clinical manifestations of liver inflammation in alcohol-associated liver disease (ALD) can range from asymptomatic to severe alcoholic hepatitis. While biopsy is the gold standard for identifying liver inflammation, it is an invasive procedure with risks of bleeding, visceral damage, and infection. We aim to establish the state of the current literature on non-invasive markers of inflammation in ALD. We searched Ovid MEDLINE, Embase, and the Cochrane Library for original studies on the association between one or more non-invasive biomarker(s) and histological inflammation or hepatitis in ALD patients. Exclusion criteria were lack of histological data, abstract only, non-English-language articles, and animal studies. Two independent reviewers screened abstracts, reviewed full texts, and extracted data from included papers. Our search identified 8051 unique studies. Title and abstract screening resulted in 563 studies, and full-text screening resulted in 31 studies for final inclusion. The majority were single-center observational cohorts with an average sample size of 124. Review of these studies identified 44 unique biomarkers and 8 calculated scores associated with histological inflammation and/or hepatitis, in addition to a metabolomic panel of 468 metabolites. Six studies examined diagnostic accuracy for histological inflammation and/or hepatitis. The highest area under the receiver operating characteristic curve was 0.932 using a model based on four metabolites. This review highlights the available literature on non-invasive markers of inflammation in ALD. There is a dearth of studies that evaluate the diagnostic accuracy of these biomarkers, and larger studies are needed to confirm findings identified in small cohorts.