Understanding the Link Between Severe Obesity and Liver Disease

Research study background

Researchers from Children’s Hospital Colorado studied adolescents and young adults with severe obesity to see if metabolic bariatric surgery reduced serious comorbidities.

“Patients with severe obesity often have a variety of comorbidities related to their weight,” says Shikha Sundaram, MD, MSCI, the study’s lead author. “They may have fatty liver disease or what we now call metabolic dysfunction-associated steatotic liver disease (MASLD). They may have Type 2 diabetes. They may have hyperlipidemia. All these things are wrapped around severe obesity.”

According to Dr. Sundaram, there is substantial existing data that suggests bariatric surgery can make a significant impact on the health of adults with MASLD, but relatively little research has been conducted to understand the effect of bariatric surgery on the adolescent population. Dr. Sundaram believes that addressing obesity-related comorbidities earlier with bariatric surgery, as adolescents, can have an even greater impact than if they were addressed later during adulthood.

Using retrospective data collected by the Bariatric Surgery Center at Children’s Colorado, researchers compared liver biopsies before and after bariatric surgery. Those with significant baseline fibrosis were re-biopsied one year after surgery to evaluate histological changes, or the microscopic alterations in the cells over time.

“We have a really robust multidisciplinary metabolic bariatric surgery clinic and program,” says Dr. Sundaram. “We chose to look retrospectively at data that already existed to understand if the obesity-related metabolic dysfunction-associated liver disease of patients who underwent the surgery got better or not.”

Findings showed that bariatric surgery led to significant improvements in liver disease biochemical markers and histology in adolescents. Researchers’ analysis of liver enzyme levels revealed that about two-thirds of patients normalized their liver enzymes within a year after surgery, with expectations (based on adult data) that further improvements would occur over time. About half of the study’s participants experienced complete resolution of their metabolic dysfunction-associated steatohepatitis, a severe form of fatty liver disease. In addition, half resolved their liver fibrosis, while the others showed only mild fibrosis after one year.

Clinical implications

The data supports considering bariatric surgery sooner for patients with both severe obesity and MASLD, as it can address both conditions and potentially prevent long-term complications. For the right candidates, bariatric surgery can significantly improve health trajectories and potentially extend lifespan by addressing comorbidities like MASLD.

Relevance to future research

Dr. Sundaram said there may be a further need to investigate how the introduction of glucagon-like peptide-1 (GLP-1) medications might influence future treatment algorithms and candidate selection. GLP-1s are a class of medications that mimic natural gut hormones to regulate appetite, slow digestion and manage blood sugar.

“Currently, injectable GLP-1s are increasingly available to patients who have obesity,” Dr. Sundaram says. “In fact, many patients cared for in our multidisciplinary bariatric program actually have been on GLP-1s of some sort, and we're pretty sure those are going to help with MASLD.”

Dr. Sundaram says there is more research that needs to be done to see how treatment for severe obesity with GLP-1s can work in conjunction with bariatric surgery. While this study shows promising results for those with severe obesity who also have comorbidities, such as MASLD or Type 2 diabetes, the next step in this research is to involve multiple centers on a larger scale to gain an even clearer understanding of how to optimize treatment for this population.