Redefining fatty liver as metabolic dysfunction-associated steatotic liver disease: Implications of nomenclature changes for patients with diabetes

Abstract

The evolving nomenclature from non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated steatotic liver disease (MASLD) aims to better encompass the metabolic context of the disease. This change has significant implications for patients with type 2 diabetes mellitus (T2DM), given the frequent overlap between these conditions. This minireview explores the rationale behind the change, compares diagnostic criteria, and evaluates the impact of the MASLD framework on disease prevalence, characterization, and outcomes in T2DM patients. The updated MASLD criteria include all individuals with T2DM and hepatic steatosis, emphasizing metabolic dysfunction as the primary driver. In contrast, the NAFLD definition necessitates excluding other chronic liver diseases and verifying the absence of significant alcohol consumption, leading to a narrower diagnostic framework. Both metabolic dysfunction-associated fatty liver disease and MASLD identify a higher prevalence of steatotic liver disease, particularly among T2DM patients, compared to NAFLD. Notably, the MASLD framework introduces metabolic and alcohol-associated liver disease to account for dual etiologies involving alcohol use, which is common in T2DM populations but previously excluded under NAFLD criteria. While the new definitions enhance clinical relevance and inclusivity, they also highlight challenges such as unrecognized medication-induced steatosis and the need for reclassification in ongoing T2DM clinical trials. Emerging evidence supports enhanced screening strategies (e.g., fibrosis-4) and metabolic-targeted treatments for MASLD in T2DM patients. The successful integration of MASLD into clinical practice will require system-wide reeducation, standardization, and multidisciplinary collaboration to improve outcomes for T2DM patients.

Keywords: Non-alcoholic fatty liver disease; Fatty liver; Diabetes mellitus; Metabolic dysfunction-associated steatotic liver disease; Type 2 diabetes mellitus

Core Tip: The transition from non-alcoholic fatty liver disease to metabolic dysfunction-associated steatotic liver disease refocuses diagnosis on metabolic dysfunction, capturing a broader spectrum of patients with type 2 diabetes mellitus and hepatic steatosis. Metabolic dysfunction-associated steatotic liver disease and its related category, metabolic and alcohol-associated liver disease, improve disease recognition, prevalence estimation, and management strategies compared to non-alcoholic fatty liver disease. This minireview highlights the clinical implications of these changes, including the need for reclassification in trials, metabolic-targeted treatments, and multidisciplinary approaches to enhance screening and outcomes in type 2 diabetes mellitus populations.