Risk of hepatic and extrahepatic outcomes associated with metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction and alcohol-associated steatotic liver disease: a systematic review and meta-analysis

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction and alcohol-associated steatotic liver disease (MetALD) are two separate entities within the spectrum of steatotic liver disease. We aimed to compare the risks of hepatic and extrahepatic outcomes between individuals with MASLD and MetALD in a comprehensive meta-analysis. METHODS: In this systematic review and meta-analysis, we systematically searched PubMed, Scopus, and the Cochrane Central Register of Controlled Trials for observational cohort studies published up to March 1, 2025, and written in English. We included studies comparing clinical outcomes between adults (>18 years) with MASLD and MetALD, if the studies incorporated appropriate statistical adjustments for known risk factors and potential confounding factors. We excluded studies that did not differentiate between MASLD and MetALD, case reports, case series, commentaries, cross-sectional or case-control studies. We evaluated each study to assess its eligibility and extracted the data. The primary outcome was liver-related events; secondary outcomes included hepatocellular carcinoma, liver-related mortality, cardiovascular events, extrahepatic cancers, and all-cause mortality. We used random-effect models to calculate pooled hazard ratios (HRs) with 95% CIs. The study was registered with PROSPERO (CRD420251003928). FINDINGS: Of 5579 records identified, we included 24 cohort studies involving 11 575 558 individuals in the analysis. 9 801 312 individuals had MASLD (mean age 57·0 years [SD 4·55], ~62% male, and ~38% female) and 1 774 246 had MetALD (mean age 48·6 years [SD 4·91], ~82% male, and ~18% female). Individuals with MetALD had significantly higher risks of liver-related events (HR 1·62, 95% CI 1·16-2·25; p=0·0086), hepatocellular carcinoma (1·33, 1·00-1·77; p=0·048), and extrahepatic cancers (1·03, 1·01-1·06; p<0·0001) compared with those with MASLD. The rates of cardiovascular events (HR 0·96, 95% CI 0·85-1·09; p=0·48), extrahepatic cancer-related mortality (1·44, 0·97-2·15; p=0·065), and all-cause mortality (1·08, 0·97-1·19; p=0·14) did not differ between the two liver conditions. Substantial heterogeneity was observed across most analyses (I2=76-93%), with only extrahepatic cancer incidence showing low heterogeneity (I2=0%). Egger's regression tests suggested that publication bias was unlikely for all outcomes except extrahepatic cancer-related mortality. INTERPRETATION: MetALD might be associated with a higher risk of liver-related events, hepatocellular carcinoma, and extrahepatic cancers than MASLD, whereas all-cause mortality, extrahepatic cancer-related mortality, and cardiovascular events seem similar between the two conditions. These findings emphasise the need for distinct clinical strategies for these related yet different entities within the steatotic liver disease spectrum and highlight the importance of conducting pharmacological clinical trials in this context. FUNDING: The Italian Ministry of Education, University, and Research (MIUR).