Bariatric surgery is usually effective on its own for weight loss, but an increasing proportion of patients who undergo bariatric surgery start taking one of the new glucagon-like 1 peptide receptor agonist (GLP-1) weight-loss drugs in the years after their surgery, according to a new study led by researchers at the Johns Hopkins Bloomberg School of Public Health.
The researchers analyzed de-identified national electronic health records covering 112,858 individuals who underwent bariatric surgery from January 2015 to May 2023. They found that 14% of those patients used a GLP-1 such as semaglutide (Wegovy) or tirzepatide (Zepbound) during a follow-up period of up to 10 years after surgery.
Severe obesity or related conditions such as type 2 diabetes pre-surgery was associated with the outcome—as was being female, and undergoing a type of bariatric surgery called sleeve gastrectomy. Individuals with lower post-operative weight loss were more likely to use GLP-1.
GLP-1 drugs were introduced to market in 2005, approved to treat type 2 diabetes, and the first GLP-1 was approved for obesity in 2014. The analysis showed that the rate of post-surgery GLP-1 use increased during the 2015–2025 study window as more powerful GLP-1 drugs such as semaglutide and tirzepatide became available.
The study was published online August 27 in JAMA Surgery.
"These findings make clear that GLP-1 drug therapy after bariatric surgery is increasingly common," said study senior author Hemalkumar Mehta , PhD, MS, an associate professor in the Bloomberg School's Department of Epidemiology. "This suggests that we need to learn more about how to optimize this combination of treatments for patients."
The U.S. adult obesity rate, currently around 40%, has been on the rise for decades. Obesity increases the risks of diabetes, heart attacks, cancer, and other ailments. Bariatric surgery has been considered one of the most effective treatments for obesity, particularly severe obesity. The surgery reduces the stomach's capacity to digest food, with patients losing one-fourth to one-third of their pre-surgery weight. About 270,000 bariatric surgeries were done in the U.S. in 2023, the most recent year for which data are available.
Despite its overall effectiveness, approximately 20% to 30% of bariatric-surgery patients' post-surgery weight loss isn't sufficient or lasting. Several clinical trials and observational studies suggest that GLP-1 drugs are effective in causing weight loss and improved blood sugar control in these cases. But little was known about the rate at which bariatric surgery patients end up using GLP-1s.
In the study, the researchers evaluated a large electronic health records database kept by a health care technology company called TriNetX. Their primary analysis focused on 112,858 American adult patients in the database who underwent one of the two most common types of bariatric surgery—sleeve gastrectomy or Roux-en-Y gastric bypass—during the period from January 2015 through May 2025, did not use GLP-1s for the year before surgery, and met other inclusion criteria.
In follow-up periods that lasted for at least two and up to 10 years, a total of 15,749 patients (14%) began using GLP-1s. About 21% of the latter began using the drugs within two years of surgery, and about 53% within four years.
The study found that, after holding other factors constant, female bariatric-surgery patients were about 61% more likely to use GLP-1 drugs compared to male patients, Black patients 27% more likely than white patients, sleeve gastrectomy patients 42% more likely than Roux-en-Y patients, and type 2 diabetes patients 34% more likely than non-diabetic patients.
The researchers also found that greater pre-operative weight was associated with higher chance of GLP-1 use. Analyzing obesity classification based on body mass index (BMI), the researchers found that compared to overweight patients (BMI between 25 and 29.9), the chances of GLP-1 use were 1.73 times higher among class 1 obesity patients (BMI between 30 and 34.9), 2.19 times higher among class 2 obesity patients (BMI between 35 and 39.9), and 2.69 times higher among patients with class 3 obesity (BMI 40 or higher)—the most severe form.
"These findings raise important questions for future obesity research," Mehta says. "For example, what is the optimal clinical threshold for prescribing a GLP-1 in terms of timing and the patient's relative weight after bariatric surgery?"
To Mehta and his colleagues, the substantial frequency of bariatric surgery plus drug therapy suggests this surgery-plus-drug combination has become routine for some patients—and is by now well studied.
"We think in the future, obesity treatment will follow that paradigm for some patients," he says. "People won't just use surgery or GLP-1s—they'll often use both."
" Use of Glucagon-like Peptide 1 Agonists Among Individuals Undergoing Bariatric Surgery in the U.S. " was co-authored by Minji Kim, Michael Schweitzer, Ji Soo Kim, G. Caleb Alexander, and Hemalkumar Mehta.
The research was supported by the National Institute on Aging (K01 AG070329).
