Research in context
Evidence before this study
Non-alcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease globally and is considered a disease of industrialised countries that is primarily associated with obesity, diabetes, and metabolic syndrome. Since Asia is a large and heterogeneous region with considerable variation in socioeconomic status and obesity prevalence, the reported overall prevalence of NAFLD is widely variable. We did a broad search of the scientific literature before intitiating this study to identify articles on NAFLD in Asia. We identified one meta-analysis on the global epidemiology of NAFLD published in 2016, the estimated pooled overall prevalence of NAFLD diagnosed by imaging in Asia was 27·37% (95% CI 23·29–31·88). We identified no systematic reviews of NAFLD prevalence, incidence, or outcome in Asia that specifically focused on NAFLD prevalence over time or the differences in prevalence between countries and regions of Asia.
Added value of this study
Understanding the disease burden within Asia has become imperative. Our systematic review and meta-analysis provides the most comprehensive assessment and robust evidence to date of the prevalence of NAFLD in Asia overall and in subgroups. Overall NAFLD prevalence in Asia regardless of diagnostic method was 29·62%, and prevalence was highest in Indonesia (51·04%) and lowest in Japan (22·28%). The overall incidence rate of NAFLD within the Asian population was 50·9 cases per 1000 person-years, the incidence rate of hepatocellular carcinoma was 1·8 cases per 1000 person-years, and overall mortality among study participants with NAFLD was 5·3 per 1000 person-years. The high prevalence of NAFLD observed in southeast Asia indicates that NAFLD is a disease that affects both individuals in areas that are rapidly becoming industrialised, suggesting that all Asian populations might be at risk. We also determined the incidence of NAFLD and the incidence of hepatocellular carcinoma and overall mortality in patients with NAFLD in the Asian population, for whom little data on NAFLD is available. We found that a large number of patients with NAFLD develop progressive liver disease, which creates challenges for screening.
Implications of all the available evidence
In this study, the prevalence of NAFLD was high in all Asian regions included and was found to be similar to that reported for western countries. The findings of our study will help stakeholders to better understand the current disease burden of NAFLD in Asia, which could lead to the development of strategies to increase disease awareness and interventions to decrease the disease burden. Future study should be devoted to defining the economic and public health burden of the NAFLD pandemic.