MAFLD enhances clinical practice for liver disease in the Asia-Pacific region

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 lean/normal-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 lean/normal-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.

Keywords: Awareness; Fatty liver; Hepatitis viruses; Leanness; Liver cancer.

Figure 1.

Definition of lean/normal weight MAFLD in the Asia-Pacific region. The definition requires ① the presence of fatty liver, ② BMI <23, and ③ at least two of the metabolic abnormalities. BMI, body mass index; HDL, high-density lipoprotein; HOMA-IR, homeostasis model assessment of insulin resistance; CRP, C-reactive protein; MAFLD, metabolic dysfunction-associated fatty liver disease.

Figure 2.

MAFLD accelerates the progression of liver disease in patients with HBV/HCV infection. Co-existing MAFLD is a higher risk for liver cirrhosis and HCC in patients with HBV and HCV infection. HBV, hepatitis B virus; HCV, hepatitis C virus; MAFLD, metabolic dysfunction-associated fatty liver disease; HCC, hepatocellular carcinoma.

Figure 3.

MAFLD renovates the etiological classification of HCC. The clinical features of HCC differ depending on its etiology. MAFLD should be categorized as an independent single etiology for HCC rather than mixing up as non-B non-C. MAFLD also allows for mixed etiology of HCC, which is frequent in the Asia-Pacific region. HCC, hepatocellular carcinoma; HBV, hepatitis B virus; HCV, hepatitis C virus; MAFLD, metabolic dysfunction-associated fatty liver disease; AIH, autoimmune hepatitis; PBC, primary biliary cholangitis.

Figure 4.

Scheme for a low-intensity resistance exercise program based on a meta-analysis. The exercise consists of six types of exercises such as (A) stepping, (B) good-morning exercises, (C) towel lat pulldowns, (D) squats, (E) calf raises, and (F) triceps surae stretching. The figure is adopted from an article by Hashida et al. [116] with permission from John Wiley and Sons.

Figure 5.

Scheme for MAFLD enhances clinical practice for liver disease in the Asia-Pacific region. HBV, hepatitis B virus; HCV, hepatitis C virus; MAFLD, metabolic dysfunction-associated fatty liver disease; HCC, hepatocellular carcinoma.