Short-Term Evolution of MASLD Following Roux-en-Y Gastric Bypass: A Focus on Fibrotic MASH

Metabolic dysfunction-associated steatotic liver disease (MASLD) includes simple steatosis and metabolic dysfuncion-associated steatohepatitis (MASH), with fibrosis in MASH serving as a critical prognostic marker. This study investigates the effects of Roux-en-Y gastric bypass (RYGB) on fibrotic MASH, assessed using the fibrotic NASH index (FNI) and the non-invasive NASH detection score (NI-NASH-DS), as well as provides further data on the diagnostic accuracy of both scores.

A retrospective cohort study was conducted involving 104 individuals (91.3% female, mean age 39.4 ± 8.6 years) who underwent RYGB. Histopathological evaluations during surgery identified fibrotic MASH, and FNI and NI-NASH-DS values were calculated at baseline and 1 year post-surgery.

At the time of surgery, participants had a mean BMI of 35.3 ± 2.8 kg/m², which decreased to 27.1 ± 4.0 kg/m² 1 year after surgery. The mean % total weight loss (%TWL) was 23.8 ± 10.1%, and the mean % excess weight loss (%EWL) was 82.4 ± 37.3%. Fibrotic MASH was present in 17.3% of participants pre-operatively. The mean FNI score significantly decreased after surgery (p < 0.0001). Female gender (p < 0.001) and histological evidence of lobular inflammation (p < 0.001) were independently associated with the improvement of FNI. The FNI demonstrated high diagnostic accuracy (sensitivity: 61.1%, specificity: 96.4%, overall accuracy: 90.2%). NI-NASH-DS had a 60% accuracy in detecting MASH, alongside an 85.9% specificity.

RYGB seemingly promotes improvement of fibrotic MASH as evaluated by FNI, highlighting its potential as a therapeutic intervention to mitigate MASLD progression. Both FNI and NI-NASH-DS are helpful and inexpensive tools for assessing MASH.