Metabolic associated steatotic liver disease misses fewer high-risk patients than metabolic associated fatty liver disease.

Metabolic associated steatotic liver disease (MASLD) was proposed to replace non-alcoholic fatty liver disease (NAFLD) in 2023. It has different diagnostic criteria from metabolic associated fatty liver disease (MAFLD). The comparison between the two disease names and diagnostic criteria deserves investigation. We recruited participants from the Taiwan Bio-bank database. NAFLD was diagnosed based on the presence of hepatic steatosis after excluding chronic hepatitis B or C virus infection, chronic drinkers, or other known liver diseases. According to the presence of cardiometabolic criteria, NAFLD is divided into two groups: MASLD and cryptogenic steatotic liver disease (SLD). The "missing" group was defined as those patients who met the diagnostic criteria for MASLD but not for MAFLD. Cryptogenic SLD was used as the control group. We used the NAFLD fibrosis score (NFS) as an indicator for liver fibrosis. This study included 17,595 participants, among whom 7,274 (41.3%) had MASLD, and 6,905 had pure MAFLD, defined as MAFLD having no other causes of liver diseases. The cryptogenic SLD group consisted of 264 (1.5%) patients, while the "missing" group had 369 patients. There were no differences in metabolic parameters, liver markers and the percentage of carotid plaques between these two groups. When comparing the "missing" group to the control group, the "missing" group had higher NFS and a higher proportion of carotid plaques. In this large, population-based study, is not advisable to exclude the "missing" group having higher risk of liver fibrosis and atherosclerosis than controls. MASLD misses fewer high-risk patients than pure MAFLD for replacing NAFLD.