Key points
Most people who have bariatric surgery lose a significant amount of weight, but some have less than optimal weight loss
Researchers studied whether a weight loss drug, liraglutide, could help them
Those taking liraglutide lost more weight than those on a placebo
Combining bariatric surgery with weight loss medication can help people who need to lose more weight post-surgery, Monash University and Alfred Health-led research has found.
Around 31 per cent of Australian adults live with obesity. Metabolic Bariatric Surgery (MBS) is the most effective and durable treatment, with most patients losing 20-30 per cent of their total body weight.
However, 10-15 per cent do not have an optimal weight loss, or regain weight after the operation.
It is not possible to predict who these people will be prior to surgery, and the only option to induce further weight loss has been more surgery, which carries a 4-5 times higher risk of a serious complication.
Given effective medications can also induce weight loss, the study was designed to see if it was possible to safely combine surgery with obesity management medications (OMM).
Published in JAMA Network Open, it used the OMM liraglutide, originally developed to manage type 2 diabetes, on patients with poor results following metabolic bariatric surgery. The double-blinded randomised controlled trial involving 48 adults saw half take daily liraglutide and the other half take a placebo.
At 12 months, the liraglutide group had a mean total body weight loss (TBWL) of 4.4 per cent compared to an increase of 1.4 per cent in the control group – a significant difference.
There were no adverse impacts on health or quality of life.
First author Professor Wendy Brown, who heads the Monash University Department of Surgery and is The Alfred's Oesophago-Gastric-Bariatric Unit Director, said the results were promising.
"We have shown that for people who regain weight or don't have an optimal weight loss effect from bariatric surgery, adding in a weight loss drug will help them to lose weight, often at a lower dose than is needed in people who have not had surgery," Professor Brown said.
"We are the first to show that the full dose of obesity management medication may not be needed in the post-bariatric surgery setting, and importantly, quality of life is not affected by introducing the obesity management medication.
"This raises the possibility of avoiding risky repeat surgery which is the current main option when people need more weight loss after bariatric surgery."
Study participants were aged 20-65, and 12-36 months post-procedures including Adjustable Gastric Band (AGB), Sleeve Gastrectomy, Roux-en-Y Gastric Bypass and One Anastomosis Gastric Bypass.
The 48 eligible patients with sub-optimal surgery results were randomised, with 24 self-administering liraglutide daily over 12 months and the other 24 taking a placebo.
"liraglutide provided greater weight loss at 12 months than placebo in a cohort of patients with a sub-optimal response to MBS," the researchers found.
Joint senior author Professor John Wentworth, an adult endocrinologist at the Royal Melbourne Hospital, said the results were exciting.
"Our demonstration that incretin drugs enhance weight loss following bariatric surgery provides great hope," Professor Wentworth said. "Excitingly, newer, more effective drugs have become available and should help our patients achieve even better weight and health outcomes."
Co-author Adjunct Associate Professor Dr Paul Burton, from the Monash University School of Translational Medicine's Department of Surgery, and The Alfred's Oesophago-Gastric and Bariatric Unit, said MBS enabled durable weight loss, improved a range of obesity-associated diseases and increased life expectancy.
However, he said up to 15 per cent of patients experienced sub-optimal weight loss and therefore less improvement in health outcomes.
"A multimodal approach has long been the guiding principle in care following weight loss surgery, but until now rested on a limited evidence base," Dr Burton said.
"The results reinforce that personalised treatment, careful patient selection, sustained lifestyle change, and ongoing adherence are essential to managing obesity as a lifelong disease we can remit but not cure.
"There are no quick fixes, but we now have increasingly effective, evidence-based treatment options. These findings support a personalised, long-term strategy that pairs surgical expertise with medication, lifestyle support, and ongoing engagement to achieve durable remission rather than a cure."
Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist, which has been studied in three previous randomised controlled trials exploring combined medication and surgery.
They also resulted in varying degrees of weight loss, suggesting a role for medications for sub-optimal weight loss after surgery.
"Combining therapies might also enable less effective yet safer and reversible procedures, such as AGB, to be re-considered as a viable option," the study found.
DOI and link to paper: 10.1001/jamanetworkopen.2025.39848
