Gastric Bypass Versus Sleeve Gastrectomy in Type 2 Diabetes: Effects on Hepatic Steatosis and Fibrosis : A Randomized Controlled Trial

Ann Intern Med. 2022 Jan;175(1):74-83. doi: 10.7326/M21-1962. Epub 2021 Nov 30.


Background: Weight loss improves fatty liver disease. No randomized trial has compared the effects of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) on liver fat content and fibrosis.

Objective: To compare the 1-year effects of SG and RYGB on hepatic steatosis and fibrosis.

Design: Single-center, randomized, controlled trial (Oseberg [ObesitySurgery in Tønsberg]). ( NCT01778738).

Setting: Tertiary care obesity center in Norway.

Participants: 100 patients (65% female; mean age, 47.5 years; mean body mass index, 42 kg/m2) with type 2 diabetes mellitus (T2DM).

Intervention: From January 2013 to February 2018, patients were randomly assigned (1:1 ratio) to SG or RYGB.

Measurements: The primary outcome was remission of T2DM (previously published). Predefined secondary outcomes in the present study were hepatic steatosis and fibrosis assessed by magnetic resonance imaging (liver fat fraction), enhanced liver fibrosis (ELF) test, noninvasive indices, and liver enzymes.

Results: Liver fat fraction declined similarly after SG (-19.7% [95% CI, -22.5% to -16.9%]) and RYGB (-21.5% [CI, -24.3% to -18.6%]) from surgery to 1-year follow-up, and almost all patients (SG, 94%; RYGB, 100%) had no or low-grade steatosis at 1 year. The ELF score category remained stable in 77% of patients, but 18% experienced worsening of fibrosis at 1 year, with no substantial between-group difference.

Limitations: Single-center study, short follow-up time, and lack of power for secondary outcomes.

Conclusion: With an almost complete clearance of liver fat 1 year after surgery, RYGB and SG were both highly effective in reducing hepatic steatosis. Bariatric surgery had less influence on degree of fibrosis in the short term, but assessment of long-term progression is warranted.

Primary funding source: Vestfold Hospital Trust and the South-Eastern Norway Regional Health Authority.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diabetes Mellitus, Type 2 / surgery*
  • Fatty Liver / surgery
  • Female
  • Gastrectomy / methods*
  • Gastric Bypass / methods*
  • Humans
  • Liver Cirrhosis / surgery
  • Male
  • Middle Aged
  • Norway
  • Obesity, Morbid / surgery*

Associated data