Serial changes in metabolic dysfunction-associated steatotic liver disease after sleeve gastrectomy and their associations with abdominal adiposity: a prospective cohort study.

Background: Little is known about the associations between changes in hepatic steatosis and changes in abdominal adiposity after metabolic bariatric surgery.

Objectives: To evaluate the serial changes in hepatic steatosis and abdominal adiposity following sleeve gastrectomy (SG).

Setting: University hospital, Taiwan.

Methods: In this prospective study, patients who underwent SG and intraoperative liver biopsy were enrolled. Magnetic resonance imaging (MRI) was performed to assess the liver fat fraction (LFF), visceral adipose tissue (VAT) area, and subcutaneous adipose tissue (SAT) area. Liver fibrosis was assessed preoperatively via biopsy and the fibrosis-4 index (FIB-4) and postoperatively with the FIB-4.

Results: Seventy-six metabolic dysfunction-associated steatotic liver disease (MASLD) patients, including 67 pure MASLD patients and 9 MASLD patients with combined etiologies, were enrolled. LFF and visceral-to-subcutaneous fat ratio were associated with metabolic dysfunction-associated steatohepatitis, and VAT area was associated with significant fibrosis (≥F2). Twelve months after SG, all MRI measurements significantly improved. The median LFF of pure MASLD patients decreased from 17.4% at baseline to 4.2% and 3.7% at the 6th and 12th postoperative months, respectively. Complete resolution of steatosis was achieved in 97.5% of patients at the 12th postoperative months. Using %VAT and %SAT reductions at the sixth postoperative month as references, LFF decreased more rapidly, with fold ratios of 1.3 and 1.8, respectively.

Conclusions: SG resulted in a significant decrease in hepatic steatosis and abdominal adiposity in patients with severe obesity, but hepatic steatosis improved faster than abdominal adiposity. Hepatic steatosis resolved in almost all patients 12 months after SG.