Two common forms of bariatric (weight-loss) surgery are both effective at improving fatty liver disease in people with type 2 diabetes and obesity, according to a new study published in the journal Annals of Internal Medicine.
Nonalcoholic fatty liver disease (NAFLD) is common in people with type 2 diabetes and obesity, and has been linked to many worse health outcomes, including a higher risk of dying at advanced stages. Studies have also shown that undiagnosed NAFLD is common in people with type 2 diabetes — meaning that many people aren’t getting the care they need to manage this condition and reduce the health risks associated with it. Certain lifestyle measures — including drinking coffee — may reduce the risk for NAFLD, but for many people with diabetes and obesity, lifestyle changes aren’t enough to substantially improve their liver health.
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For the latest study, researchers set out to compare liver outcomes after two common forms of bariatric surgery — gastric bypass and sleeve gastrectomy. Gastric bypass involves closing off part of the stomach to create a small pouch, which is connected to your small intestine — with most of your stomach and part of your small intestine cut off from your digestive pathway, but not removed. Sleeve gastrectomy, on the other hand, involves reducing the size of the stomach to a narrow sleeve and removing the remaining portion of the stomach. While both of these surgeries can lead to weight loss and other improvements in people with type 2 diabetes and obesity, some research suggests that gastric bypass may be more effective at improving blood glucose levels and reducing cardiovascular risks.
A total of 100 people with type 2 diabetes and obesity underwent bariatric surgery as part of the study, with participants randomly assigned to either gastric bypass or sleeve gastrectomy. The average age of participants was 47.5, and 65% were female. The average body-mass index (BMI, a measure of body weight that takes height into account) was 42, indicating severe obesity. Participants underwent surgery between January 2013 and February 2018, and were followed for a year afterward as part of the study.
Liver fat reductions after bariatric surgery
The researchers found similar reductions in liver fat after both forms of bariatric surgery — with participants losing an average of 19.7% of liver fat after sleeve gastrectomy, and 21.5% of liver fat after gastric bypass a year later. Almost all participants had no or only low-level steatosis — the liver changes that characterize fatty liver disease — at their one-year follow-up, with 94% of those who underwent sleeve gastrectomy and 100% of those who underwent gastric bypass experiencing this outcome. When it came to looking at liver fibrosis — changes to the liver that can lead to long-term damage — this measurement was stable in 77% of participants and worsened in 18%, with no meaningful differences between the two surgery groups.
“With an almost complete clearance of liver fat 1 year after surgery, [gastric bypass and sleeve gastrectomy] were both highly effective in reducing hepatic steatosis,” the researchers concluded. “Bariatric surgery had less influence on degree of fibrosis in the short term, but assessment of long-term progression is warranted.”