Clinical profiles and mortality rates are similar for metabolic dysfunction-associated steatotic liver disease and non-alcoholic fatty liver disease

Background Metabolic dysfunction associated steatotic liver disease (MASLD) has replaced nonalcoholic fatty liver disease (NAFLD). Concern remains whether the evidence generated under NAFLD definition can be used for MASLD. We compared the clinical profile and outcomes of NAFLD to MASLD using tertiary-care and population-based data. Methods Comparison data were obtained from NAFLD database and National Health and Nutrition Examination Survey (NHANES-III). Clinical profiles and non-invasive tests (ELF, FIB-4 and Transient elastography) were compared. NHANES-National Death Index provided mortality data. All-cause mortality by Cox proportional hazards regression models (HRs); cause-specific mortality by competitive risk analysis. Results There were 6429 NAFLD patients in the tertiary care database (age: 54±12 years, 42% male, BMI:35.4±8.3; waist circumference:112±17 cm;52% T2D). Average scores for ELF, FIB-4 and liver stiffness were 9.6±1.2, 1.69±1.24,14.0±11.8 kPa, respectively; 99% met MASLD criteria; 95% met MASLD on BMI only. Predictive accuracy of ELF and FIB-4 were identical between MASLD and NAFLD. Among 12,519 NHANES NAFLD participants (age 43.00 years, 47.38% male, 22.70% obese, 7.28% T2D, 82.51% ≥ 1 cardiometabolic criteria), there was excellent concordance between MASLD and NAFLD: Cohen’s kappa coefficient:0.968 (95% CI: 0.962-0.973) with 5.29% of NAFLD not meeting MASLD criteria. After a median follow-up of 22.83 years, there were no mortality differences between MASLD and NAFLD (p-values ≥ 0.05). Conclusions NAFLD and MASLD were similar except MASLD subjects were older with slightly higher mortality risk due to cardiometabolic risk factors inclusion. Clinical profiles and NIT thresholds are identical. These data provide evidence that NAFLD and MASLD can be used interchangeably.