Published online Mar 27, 2024. doi: 10.4254/wjh.v16.i3.452
Peer-review started: December 26, 2023
First decision: January 11, 2024
Revised: January 19, 2024
Accepted: February 28, 2024
Article in press: February 28, 2024
Published online: March 27, 2024
Processing time: 92 Days and 11.6 Hours
Metabolic dysfunction-associated steatotic liver disease (MASLD) is the new nomenclature of non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD). It is a complex condition, and its mechanism is poorly understood. There are several studies involving overweight/obese patients but there is very limited literature available regarding lean patients.
Only one clinical guideline is available for physicians to diagnosis and manage lean patients with MASLD. However, the pathogenesis, accurate treatment, risk factor and outcomes remain unknown.
The aim of this systematic review is to report literature of diagnosis, pathogenesis, characteristics, and prognosis in lean MASLD patients in diverse populations, and provide an interpretation of the new MASLD criteria.
A search on two large databases was conducted, PubMed and Google Scholar, selecting original articles published between January 2012 and September 2023 specifically focusing on lean NAFLD, MAFLD, or MASLD patients.
85 articles met the eligibility criteria and underwent further analysis. The prevalence of lean MASLD among diverse populations ranges from 4% to 34%. The pathogenesis of lean MASLD involves genetic, epigenetic, and metabolic factors; however, the mechanism remains elusive. Although adequate treatment remains challenging to identify, lifestyle modifications have proven effective in reducing hepatic steatosis and improving cardiometabolic profiles. Some medications have shown efficacy to a lesser extent.
MASLD is a complex condition that requires attention, especially in lean patients. Risk factors and metabolic conditions are associated with this condition independently of BMI. Therefore, investigations aimed at decreasing the risk of future complications, such as cirrhosis or the development of hepatocellular carcinoma in lean MASLD patient, are necessary with the same relevance as in overweight/obese counterparts.
Future studies using this new nomenclature of MASLD can contribute to standardizing and generalizing study results in lean patients with steatotic liver diseases. It is also important to take into consideration other values, such as muscle mass or waist circumference and not only BMI, to make a more accurate evaluation of the lean patients.