ABSTRACT
Background/Aims@#Metabolic dysfunction-associated steatotic liver disease (MASLD) was recently proposed as an alternative disease concept to nonalcoholic fatty liver disease (NAFLD). We aimed to investigate the prognosis of patients with biopsy-confirmed MASLD using data from a multicenter study. @*Methods@#This was a sub-analysis of the Clinical Outcome Nonalcoholic Fatty Liver Disease (CLIONE) study that included 1,398 patients with NAFLD. Liver biopsy specimens were pathologically diagnosed and histologically scored using the NASH Clinical Research Network system, the FLIP algorithm, and the SAF score. Patients who met at least one cardiometabolic criterion were diagnosed with MASLD. @*Results@#Approximately 99% of cases (n=1,381) were classified as MASLD. Patients with no cardiometabolic risk (n=17) had a significantly lower BMI than patients with MASLD (20.9 kg/m2 vs. 28.0 kg/m2, P<0.001), in addition to significantly lower levels of inflammation, ballooning, NAFLD activity score, and fibrosis stage based on liver histology. These 17 patients had a median follow-up of 5.9 years, equivalent to 115 person-years, with no deaths, liver-related events, cardiovascular events, or extrahepatic cancers. The results showed that the prognosis for pure MASLD was similar to that for the original CLIONE cohort, with 47 deaths and one patient who underwent orthotopic liver transplantation. The leading cause of death was extrahepatic cancer (n=10), while the leading causes of liver-related death were liver failure (n=9), hepatocellular carcinoma (n=8), and cholangiocarcinoma (n=4). @*Conclusions@#Approximately 99% of NAFLD cases were considered MASLD based on the 2023 liver disease nomenclature. The NAFLD-only group, which is not encompassed by MASLD, had a relatively mild histopathologic severity and a favorable prognosis. Consequently, the prognosis of MASLD is similar to that previously reported for NAFLD.
ABSTRACT
Fatty liver is now a major cause of liver disease in the Asia-Pacific region. Liver diseases in this region have distinctive characteristics. First, fatty liver is frequently observed in leanormal-weight individuals. However, there is no standard definition of this unique phenotype. Second, fatty liver is often observed in patients with concomitant viral hepatitis. The exclusion of viral hepatitis from non-alcoholic fatty liver disease limits its value and detracts from the investigation and holistic management of coexisting fatty liver in patients with viral hepatitis. Third, fatty liver-associated hepatocellular carcinoma (HCC) is generally categorized as non-B non-C HCC. Fourth, the population is aging rapidly, and it is imperative to develop a practicable, low-intensity exercise program for elderly patients. Fifth, most patients and nonspecialized healthcare professionals still lack an awareness of the significance of fatty liver both in terms of intrahepatic and extrahepatic disease and cancer. Recently, an international expert panel proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). One feature of MAFLD is that metabolic dysfunction is a prerequisite for diagnosis. Pertinent to regional issues, MAFLD also provides its diagnostic criteria in leanormal-weight individuals. Furthermore, MAFLD is independent of any concomitant liver disease, including viral hepatitis. Therefore, MAFLD may be a more suitable definition for fatty liver in the Asia-Pacific region. In this review, we introduce the regional characteristics of fatty liver and discuss the advantages of MAFLD for improving clinical practice for liver disease in the region.