Both Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) are effective at improving hepatic steatosis in type 2 diabetes patients, according to a new analysis of a randomized, controlled trial.
Both procedures resulted in near elimination of liver fat 1 year after the surgery, but the effect on liver fibrosis was less clear. The authors called for more research to examine longer-term effects on fibrosis.
Dr. Jens Kristoffer Hertel
“Both gastric bypass and the sleeve had complete resolution of the liver fat based on their MRI findings. That’s impressive,” said Ali Aminian, MD, who was asked to comment on the study. Dr. Aminian is a professor of surgery and director of the Bariatric & Metabolic Institute at the Cleveland Clinic.
About 25% of the general population, and about 90% of people with type 2 diabetes and obesity have nonalcoholic fatty liver disease (NAFLD), which can lead to liver failure or hepatocellular carcinoma. Hepatic steatosis can combine with obesity, insulin resistance, and inflammation to heighten the risk of cardiovascular disease.
Moderate weight loss can clear liver fat and lead to histologic improvement of hepatic steatosis, and retrospective studies have suggested that RYGB may be more effective than SG and gastric banding in countering hepatic steatosis and steatohepatitis.
In fact, Dr. Aminian recently coauthored a paper describing results from the SPLENDOR study, which looked at 650 adults with obesity and nonalcoholic steatohepatitis (NASH) who underwent bariatric surgery at U.S. hospitals between 2004 and 2016, and compared liver biopsy outcomes to 508 patients who went through nonsurgical weight loss protocols.
After a median follow-up of 7 years, 2.3% In the bariatric surgery group had major adverse liver outcomes, compared with 9.6% in the nonsurgical group (adjusted hazard ratio, 0.12; P = .01). The cumulative incidence of major adverse cardiovascular events (MACE) was 8.5% in the bariatric surgery group and 15.7% in the nonsurgery group (aHR, 0.30; P = .007). 0.6% of the surgical group died within the first year after surgery from surgical complications.
Still, the question has not been tested in a randomized, controlled trial.
In the study published online in the Annals of Internal Medicine, researchers led by Kathrine Aglen Seeberg, MD, and Jens Kristoffer Hertel, PhD, of Vestfold Hospital Trust, Tønsberg, Norway, conducted a prespecified secondary analysis of data from 100 patients (65% female, mean age, 47.5 years) with type 2 diabetes who had been randomized to undergo RYGB or SG between January 2013 and February 2018 at their center.
Prior to surgery, the mean liver fat fraction (LFF) was 19% (stand deviation, 12%). In the SG and RYGB groups, 24% and 26% of patients had no or low-grade steatosis (LFF ≤ 10%). LFF declined by 13% in both groups at 5 weeks, and by 20% and 22% at 1 year, respectively, with no significant difference between the two groups.
At 1 year, 100% of the RYGB group had no or low-grade steatosis, as did 94% in the SG group (no significant difference). At 1 year, both groups had similar percentage decreases in the NAFLD liver fat score (between group difference, –0.05) and NAFLD liver fat percentage (between-group difference, –0.3; no significant difference for either).
At baseline, 6% of the RYGB group and 8% of the SG group had severe fibrosis as measured by the enhanced liver fibrosis (ELF) test. At 1 year, the respective frequencies were 9% and 15%, which were not statistically significant changes.
There was much variation in ELF score changes between Individuals, but 18% moved to a higher ELF category and only 5% improved to a lower ELF category at 1 year.
Limitations of the study include the fact that it was conducted at a single center and in a predominantly White population. The study also did not use liver biopsy, which is the standard for measuring fibrosis. Individuals with type 2 diabetes may have more severe NAFLD, which could limit the applicability to individuals without type 2 diabetes.
Together, the studies produce a clear clinical message, according to Dr. Aminian. “It provides compelling evidence for patients and medical providers that, if we can help patients lose weight, we can reverse fatty liver disease,” he said.
The study was funded by the Southeastern Norway Regional Health Authority. Dr. Aminian has received research support from Medtronic.