Validation of NIAAAm-CRP criteria to predict alcohol-associated steatohepatitis on liver histology

Background & Aims In clinical practice diagnosis of alcohol-associated hepatitis (AH) is mostly based on noninvasive criteria based on expert opinion, which were defined at a consensus conference by the National Institute on Alcohol Abuse and Alcoholism (NIAAA). These criteria were recently modified by adding C-reactive protein (CRP) and termed NIAAAm-CRP criteria, which showed superior diagnostic accuracy for presence of alcohol-associated steatohepatitis (ASH) on liver histology. The aim of our study was to validate the diagnostic accuracy of both original NIAAA criteria and NIAAAm-CRP criteria for presence of ASH on liver histology in an independent cohort. Methods Data from a large multinational cohort of 445 patients with alcohol-associated liver disease (ALD) that served to establish a novel grading and staging system of alcohol-associated liver disease were analyzed retrospectively. Diagnosis of ASH was based on presence of hepatocyte ballooning plus lobular neutrophil infiltration and established in virtual consensus meetings of multiple expert liver pathologists. Results Complete data including CRP values were available in 346 patients. Overall diagnostic accuracy for prediction of ASH was 73% for NIAAA criteria and 77% for NIAAAm-CRP criteria. In a subgroup with suspected severe AH (MELD >20, n=123), overall diagnostic accuracy for prediction of ASH was 69% for NIAAA criteria and 74% for NIAAAm-CRP criteria. Conclusion Our findings confirm recent data on suboptimal diagnostic accuracy of original NIAAA criteria and validate slightly better but still suboptimal performance of NIAAAm-CRP criteria for presence of ASH. Impact and Implications Alcohol-associated steatohepatitis (ASH) is diagnosed on liver histology but liver biopsy is not always feasible. Noninvasive diagnosis based on clinical findings has been proposed using the National Institute on Alcohol Abuse and Alcoholism (NIAAA) criteria and recently improved using NIAAAm-CRP criteria. Our findings validate slightly better but still suboptimal performance of NIAAAm-CRP criteria for presence of histological ASH. Clinical trials of novel drugs should focus on histologically proven ASH.