Agreement Between the Prevalence of Nonalcoholic Fatty Liver Disease Determined by Transient Elastography and Fatty Liver Indices.

Nonalcoholic fatty liver disease (NAFLD) is a global public health problem linked to the rising prevalence of obesity and metabolic disorders. Accurate estimates of NAFLD in populations are challenging because the gold standard for detection is liver biopsy, an invasive procedure that precludes its use in research settings. NAFLD can also be detected via noninvasive imaging, such as ultrasound, magnetic resonance imaging-determined proton density fat fraction, magnetic resonance spectroscopy, and the controlled attenuation parameter derived via transient elastography (CAP-TE). Given the complexities of imaging in population studies, however, many estimates have been based on calculated indices, such as the Fatty Liver Index (FLI) and the Hepatic Steatosis Index (HSI). Concern has been raised that the indices underestimate the prevalence of NAFLD, thus downplaying the scope of the public health challenge. Ability to examine whether these concerns are substantive has been provided by a recent study of the US population. Using data from the study, it was reported that the US prevalence of CAP-TE-determined NAFLD was 47.8%. The current analysis used data from the same national study to examine how well the fatty liver indices corresponded to CAP-TE-determined NAFLD. Because most persons with NAFLD reportedly have elevated alanine aminotransferase (ALT) levels, the correspondence between elevated ALT and CAP-TE was also examined.