Global Prevalence and Clinical Characteristics of Metabolic-associated Fatty Liver Disease: A Meta-Analysis and Systematic Review of 10 739 607 Individuals

Background and Aims: Metabolic-associated fatty liver disease (MAFLD) was proposed as a better definition of nonalcoholic fatty liver disease (NAFLD) to encompass the metabolic dysregulation associated with NAFLD. This redefinition challenges our understanding of the disease. Hence, this study sought to conduct an updated analysis of the prevalence, clinical characteristics, and associated factors of MAFLD, with a further sensitivity analysis done based on lean and nonobese MAFLD individuals. Methods: Medline and Embase databases were searched to include articles on MAFLD. Meta-analysis of proportions was conducted using the generalized linear mix model. Associating factors were evaluated in conventional pairwise meta-analysis with sensitivity analysis on lean and nonobese MAFLD. Results: From pooled analysis involving 3 320 108 individuals, the overall prevalence of MAFLD was 38.77% (95% CI 32.94% to 44.95%); 5.37% (95% CI 4.36% to 6.59%) and 29.78% (95% CI 26.06% to 33.79%) of lean and nonobese individuals, respectively, had MAFLD. Metabolic complications such as hypertension [odds ratio (OR) 2.63, 95% CI 1.85 to 3.74, P<0.0001 and OR 2.03; 95% CI 1.74 to 2.38, P<0.0001, respectively] and diabetes (OR 3.80, 95% CI 2.65 to 5.43, P<0.0001 and OR 3.46, 95% CI 2.81 to 4.27, P<0.0001, respectively) were found as significant associating factors associated with lean and nonobese MAFLD. Conclusions: This meta-analysis supports previous studies in reporting MAFLD to affect more than a third of the global population. While exploration of the pathogenic basis of fatty liver disease without metabolic dysregulation is required, the emphasis on management of concomitant metabolic disease in MAFLD can improve multidisciplinary efforts in managing the complex disease.