Background & aims: The shift to redefine nonalcoholic fatty liver disease (NAFLD) as metabolic associated fatty liver disease (MAFLD) can profoundly affect patient care, health care professionals, and progress within the field. To date, there remains no consensus on the characterization of NAFLD vs MAFLD. Thus, this study sought to compare the differences between the natural history of NAFLD and MAFLD.
Methods: Medline and Embase databases were searched to include articles on prevalence, risk factors, or outcomes of patients with MAFLD or NAFLD. Meta-analysis of proportions was conducted using the generalized linear mix model. Risk factors and outcomes were evaluated in conventional pairwise meta-analysis.
Results: Twenty-two articles involving 379,801 patients were included. Pooled prevalence of MAFLD was 39.22% (95% confidence interval [CI], 30.96%-48.15%) with the highest prevalence in Europe and Asia, followed by North America. The current MAFLD Definition only accounted for 81.59% (95% CI, 66.51%-90.82%) of NAFLD diagnoses. Patients had increased odds of being diagnosed with MAFLD compared with NAFLD (odds ratio, 1.37; 95% CI, 1.16-1.63; P < .001). Imaging modality resulted in a significantly higher odds of being diagnosed with MAFLD compared with NAFLD, but not biopsy. MAFLD was significantly associated with males, higher body mass index, hypertension, diabetes, lipids, transaminitis, and greater fibrosis scores compared with NAFLD.
Conclusions: There were stark differences in the prevalence and risk factors between MAFLD and NAFLD. However, in the use of the MAFLD Definition, a greater emphasis on the management of concomitant metabolic diseases and a collaborative effort is required to explore the complex pathophysiologic mechanisms underlying the disease.
Keywords: Liver Diseases; Metabolic Associated Fatty Liver Disease; Nonalcoholic Fatty Liver Disease; Prevalence; Risk Factors.
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