AGA Clinical Practice Update: Diagnosis and Management of Nonalcoholic Fatty Liver Disease in Lean Individuals: Expert Review.

descriptionNonalcoholic fatty liver disease (NAFLD) is well recognized as a leading etiology for chronic liver disease, affecting >25% of the US and global populations. Up to 1 in 4 individuals with NAFLD have nonalcoholic steatohepatitis, which is associated with significant morbidity and mortality due to complications of liver cirrhosis, hepatic decompensation, and hepatocellular carcinoma. Although NAFLD is observed predominantly in persons with obesity and/or type 2 diabetes mellitus, an estimated 7%-20% of individuals with NAFLD have lean body habitus. Limited guidance is available to clinicians on appropriate clinical evaluation in lean individuals with NAFLD, such as for inherited/genetic disorders, lipodystrophy, drug-induced NAFLD, and inflammatory disorders. Emerging data now provide more robust evidence to define the epidemiology, natural history, prognosis, and mortality of lean individuals with NAFLD. Multiple studies have found that NAFLD among lean individuals is associated with increased cardiovascular, liver, and all-cause mortality relative to those without NAFLD. This American Gastroenterological Association Clinical Practice Update provides Best Practice Advice to assist clinicians in evidence-based approaches to the diagnosis, staging, and management of NAFLD in lean individuals.

methodsThis expert review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Gastroenterology. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Lean NAFLD should be diagnosed in individuals with NAFLD and body mass index <25 kg/m