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The proportion of patients taking a GLP-1 weight-loss drug following bariatric surgery increased substantially in recent years, although the timing of initiation after surgery varied widely, a large retrospective cohort study showed.

GLP-1 initiation was also more common among women, those who underwent sleeve gastrectomy, and those with lower postoperative weight loss as measured by BMI.

“Some patients do not lose as much weight as expected, or they regain weight after a few years. In such cases, GLP-1 therapies are emerging as an important option for weight management,” said principal investigator Hemalkumar Mehta, PhD, associate professor at Johns Hopkins Bloomberg School of Public Health in Baltimore. 

“We also noted many personal stories circulating on social media in which patients shared their experiences using GLP-1 after bariatric surgery,” he told GI & Hepatology News

But when the researchers reviewed the scientific literature, they found no published evidence on GLP-1 use in this setting and little or no data on outcomes with the newer drugs such as semaglutide and tirzepatide. “This gap motivated us to conduct the current study,” said Mehta. The study was published in JAMA Surgery.

The researchers analyzed data from a national multicenter database of electronic health records of approximately 113 million US adults to characterize the use of and factors associated with GLP-1 initiation after bariatric surgery.

Among 112,858 individuals undergoing bariatric surgery during the study period, the mean age was 45.2 years, and 78.9% were women.

By self-report race, 1.1% were Asian, 22.1% were Black or African American, 64.2% were White individuals, and 12.6% reported belonging to other races (American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, or unknown).

A total of 15,749 individuals (14%) initiated GLP-1s post-surgery, with 3391 (21.5%) beginning within 2 years of surgery and the remainder initiating during postsurgical years 3-4 (32.3%), 5-6 (25.2%), or later (21%).

Notably, the proportion of GLP-1 use increased more in the more recent cohort, from 1.7% in the January 2015-December 2019 cohort to 12.6% from June 2020 to May 2025.

 

Differences Between Users and Nonusers

Those who initiated GLP-1s differed significantly from those who did not: GLP-1 users vs nonusers were younger (mean age, 44.9 years vs 45.2 years), and use was more common among women vs men (15.1% vs 9.7%), among Black or African American vs White patients (15.8% vs 13.5%), and among those who underwent sleeve gastrectomy vs Roux-en-Y gastric bypass (14.9% vs 12.1%).

Looked at another way, women (adjusted hazard ratio [aHR], 1.61), those undergoing sleeve gastrectomy (aHR, 1.42), and those with type 2 diabetes (aHR, 1.34) were more likely to initiate GLP-1s than their counterparts.

The overall median presurgical BMI was 42. On analyzing obesity classification based on BMI, the researchers found that the chances of GLP-1 use were 1.73 times higher among class 1 obesity patients (BMI, 30.0-34.9), 2.19 times higher among class 2 obesity patients (BMI, 35.0-39.9), and 2.69 times higher among patients with class 3 obesity (BMI ≥ 40) than among overweight patients (BMI, 25.0-29.9).

The median post-surgery BMI for GLP-1 users at drug initiation was 36.7. Each one-unit increase in postsurgical BMI was associated with an 8% increase in the likelihood of GLP-1 initiation (aHR, 1.08).

“Importantly, our study did not specifically evaluate the effectiveness of GLP-1 therapy on weight loss after surgery,” Mehta noted. That issue and others, such as optimal timing for initiating GLP-1s, are currently under investigation.

In a related editorial, Kate Lauer, MD, of the University of Wisconsin-Madison and colleagues noted that the study had several limitations. It relied on data prior to the USFDA approvals of semaglutide and tirzepatide, the two most prescribed GLP-1s currently, potentially limiting its applicability to current practice.

Furthermore, the prescribing data did not capture dose, titration schedules, or adherence, which are “critical for understanding treatment efficacy,” they wrote. “Nonetheless, the findings highlight two important trends: (1) GLP-1s are being increasingly used as an adjunct after bariatric surgery, and (2) there is substantial variability in the timing of their initiation.”

 

‘Logical’ to Use GLP-1s Post Surgery

Commenting on the study findings for GI & Hepatology News, Louis Aronne, MD, director of the Comprehensive Weight Control Center at Weill Cornell Medicine in New York City, who was not involved in the study, said, “I think it is perfectly logical to use GLP-1s in patients who have had bariatric surgery.”

In this study, weight loss in those who took GLP-1s was about 12% (from a median BMI of 42 pre-surgery to 36.7 when a GLP-1 was initiated), which is significantly less than average, Aronne noted. “The patients still had Class 2 obesity.”

“Obesity is the same as other metabolic diseases,” he added. “We have to use common sense and good medical judgment when treating patients. If surgery isn’t completely effective and weight loss is inadequate, I would recommend medications.”

Of note, his team has found that lower doses of GLP-1s are required in those who have had surgery than in those who have not. “My opinion is that patients who have undergone bariatric surgery seem to be more sensitive to the medications than the average patient, but this hasn’t been carefully studied.”

To prepare patients for the possible use of GLP1s post-surgery, he suggested telling those with very high BMI that “they may need medication in addition to the procedure in order to get the best result.”

Mehta added, “Ultimately, the decision to start GLP-1s after surgery is shared between patients and clinicians. Given the amount of media coverage on GLP-1 therapies, it is not surprising that more patients are initiating these discussions with their doctors.”

Mehta is supported by the US National Institute on Aging and reported receiving grants from the institute for this study; no other funding was reported. Lauer reported receiving grants from the US National Institutes of Health.

A version of this article first appeared on Medscape.com.

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The proportion of patients taking a GLP-1 weight-loss drug following bariatric surgery increased substantially in recent years, although the timing of initiation after surgery varied widely, a large retrospective cohort study showed.

GLP-1 initiation was also more common among women, those who underwent sleeve gastrectomy, and those with lower postoperative weight loss as measured by BMI.

“Some patients do not lose as much weight as expected, or they regain weight after a few years. In such cases, GLP-1 therapies are emerging as an important option for weight management,” said principal investigator Hemalkumar Mehta, PhD, associate professor at Johns Hopkins Bloomberg School of Public Health in Baltimore. 

“We also noted many personal stories circulating on social media in which patients shared their experiences using GLP-1 after bariatric surgery,” he told GI & Hepatology News

But when the researchers reviewed the scientific literature, they found no published evidence on GLP-1 use in this setting and little or no data on outcomes with the newer drugs such as semaglutide and tirzepatide. “This gap motivated us to conduct the current study,” said Mehta. The study was published in JAMA Surgery.

The researchers analyzed data from a national multicenter database of electronic health records of approximately 113 million US adults to characterize the use of and factors associated with GLP-1 initiation after bariatric surgery.

Among 112,858 individuals undergoing bariatric surgery during the study period, the mean age was 45.2 years, and 78.9% were women.

By self-report race, 1.1% were Asian, 22.1% were Black or African American, 64.2% were White individuals, and 12.6% reported belonging to other races (American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, or unknown).

A total of 15,749 individuals (14%) initiated GLP-1s post-surgery, with 3391 (21.5%) beginning within 2 years of surgery and the remainder initiating during postsurgical years 3-4 (32.3%), 5-6 (25.2%), or later (21%).

Notably, the proportion of GLP-1 use increased more in the more recent cohort, from 1.7% in the January 2015-December 2019 cohort to 12.6% from June 2020 to May 2025.

 

Differences Between Users and Nonusers

Those who initiated GLP-1s differed significantly from those who did not: GLP-1 users vs nonusers were younger (mean age, 44.9 years vs 45.2 years), and use was more common among women vs men (15.1% vs 9.7%), among Black or African American vs White patients (15.8% vs 13.5%), and among those who underwent sleeve gastrectomy vs Roux-en-Y gastric bypass (14.9% vs 12.1%).

Looked at another way, women (adjusted hazard ratio [aHR], 1.61), those undergoing sleeve gastrectomy (aHR, 1.42), and those with type 2 diabetes (aHR, 1.34) were more likely to initiate GLP-1s than their counterparts.

The overall median presurgical BMI was 42. On analyzing obesity classification based on BMI, the researchers found that the chances of GLP-1 use were 1.73 times higher among class 1 obesity patients (BMI, 30.0-34.9), 2.19 times higher among class 2 obesity patients (BMI, 35.0-39.9), and 2.69 times higher among patients with class 3 obesity (BMI ≥ 40) than among overweight patients (BMI, 25.0-29.9).

The median post-surgery BMI for GLP-1 users at drug initiation was 36.7. Each one-unit increase in postsurgical BMI was associated with an 8% increase in the likelihood of GLP-1 initiation (aHR, 1.08).

“Importantly, our study did not specifically evaluate the effectiveness of GLP-1 therapy on weight loss after surgery,” Mehta noted. That issue and others, such as optimal timing for initiating GLP-1s, are currently under investigation.

In a related editorial, Kate Lauer, MD, of the University of Wisconsin-Madison and colleagues noted that the study had several limitations. It relied on data prior to the USFDA approvals of semaglutide and tirzepatide, the two most prescribed GLP-1s currently, potentially limiting its applicability to current practice.

Furthermore, the prescribing data did not capture dose, titration schedules, or adherence, which are “critical for understanding treatment efficacy,” they wrote. “Nonetheless, the findings highlight two important trends: (1) GLP-1s are being increasingly used as an adjunct after bariatric surgery, and (2) there is substantial variability in the timing of their initiation.”

 

‘Logical’ to Use GLP-1s Post Surgery

Commenting on the study findings for GI & Hepatology News, Louis Aronne, MD, director of the Comprehensive Weight Control Center at Weill Cornell Medicine in New York City, who was not involved in the study, said, “I think it is perfectly logical to use GLP-1s in patients who have had bariatric surgery.”

In this study, weight loss in those who took GLP-1s was about 12% (from a median BMI of 42 pre-surgery to 36.7 when a GLP-1 was initiated), which is significantly less than average, Aronne noted. “The patients still had Class 2 obesity.”

“Obesity is the same as other metabolic diseases,” he added. “We have to use common sense and good medical judgment when treating patients. If surgery isn’t completely effective and weight loss is inadequate, I would recommend medications.”

Of note, his team has found that lower doses of GLP-1s are required in those who have had surgery than in those who have not. “My opinion is that patients who have undergone bariatric surgery seem to be more sensitive to the medications than the average patient, but this hasn’t been carefully studied.”

To prepare patients for the possible use of GLP1s post-surgery, he suggested telling those with very high BMI that “they may need medication in addition to the procedure in order to get the best result.”

Mehta added, “Ultimately, the decision to start GLP-1s after surgery is shared between patients and clinicians. Given the amount of media coverage on GLP-1 therapies, it is not surprising that more patients are initiating these discussions with their doctors.”

Mehta is supported by the US National Institute on Aging and reported receiving grants from the institute for this study; no other funding was reported. Lauer reported receiving grants from the US National Institutes of Health.

A version of this article first appeared on Medscape.com.

The proportion of patients taking a GLP-1 weight-loss drug following bariatric surgery increased substantially in recent years, although the timing of initiation after surgery varied widely, a large retrospective cohort study showed.

GLP-1 initiation was also more common among women, those who underwent sleeve gastrectomy, and those with lower postoperative weight loss as measured by BMI.

“Some patients do not lose as much weight as expected, or they regain weight after a few years. In such cases, GLP-1 therapies are emerging as an important option for weight management,” said principal investigator Hemalkumar Mehta, PhD, associate professor at Johns Hopkins Bloomberg School of Public Health in Baltimore. 

“We also noted many personal stories circulating on social media in which patients shared their experiences using GLP-1 after bariatric surgery,” he told GI & Hepatology News

But when the researchers reviewed the scientific literature, they found no published evidence on GLP-1 use in this setting and little or no data on outcomes with the newer drugs such as semaglutide and tirzepatide. “This gap motivated us to conduct the current study,” said Mehta. The study was published in JAMA Surgery.

The researchers analyzed data from a national multicenter database of electronic health records of approximately 113 million US adults to characterize the use of and factors associated with GLP-1 initiation after bariatric surgery.

Among 112,858 individuals undergoing bariatric surgery during the study period, the mean age was 45.2 years, and 78.9% were women.

By self-report race, 1.1% were Asian, 22.1% were Black or African American, 64.2% were White individuals, and 12.6% reported belonging to other races (American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, or unknown).

A total of 15,749 individuals (14%) initiated GLP-1s post-surgery, with 3391 (21.5%) beginning within 2 years of surgery and the remainder initiating during postsurgical years 3-4 (32.3%), 5-6 (25.2%), or later (21%).

Notably, the proportion of GLP-1 use increased more in the more recent cohort, from 1.7% in the January 2015-December 2019 cohort to 12.6% from June 2020 to May 2025.

 

Differences Between Users and Nonusers

Those who initiated GLP-1s differed significantly from those who did not: GLP-1 users vs nonusers were younger (mean age, 44.9 years vs 45.2 years), and use was more common among women vs men (15.1% vs 9.7%), among Black or African American vs White patients (15.8% vs 13.5%), and among those who underwent sleeve gastrectomy vs Roux-en-Y gastric bypass (14.9% vs 12.1%).

Looked at another way, women (adjusted hazard ratio [aHR], 1.61), those undergoing sleeve gastrectomy (aHR, 1.42), and those with type 2 diabetes (aHR, 1.34) were more likely to initiate GLP-1s than their counterparts.

The overall median presurgical BMI was 42. On analyzing obesity classification based on BMI, the researchers found that the chances of GLP-1 use were 1.73 times higher among class 1 obesity patients (BMI, 30.0-34.9), 2.19 times higher among class 2 obesity patients (BMI, 35.0-39.9), and 2.69 times higher among patients with class 3 obesity (BMI ≥ 40) than among overweight patients (BMI, 25.0-29.9).

The median post-surgery BMI for GLP-1 users at drug initiation was 36.7. Each one-unit increase in postsurgical BMI was associated with an 8% increase in the likelihood of GLP-1 initiation (aHR, 1.08).

“Importantly, our study did not specifically evaluate the effectiveness of GLP-1 therapy on weight loss after surgery,” Mehta noted. That issue and others, such as optimal timing for initiating GLP-1s, are currently under investigation.

In a related editorial, Kate Lauer, MD, of the University of Wisconsin-Madison and colleagues noted that the study had several limitations. It relied on data prior to the USFDA approvals of semaglutide and tirzepatide, the two most prescribed GLP-1s currently, potentially limiting its applicability to current practice.

Furthermore, the prescribing data did not capture dose, titration schedules, or adherence, which are “critical for understanding treatment efficacy,” they wrote. “Nonetheless, the findings highlight two important trends: (1) GLP-1s are being increasingly used as an adjunct after bariatric surgery, and (2) there is substantial variability in the timing of their initiation.”

 

‘Logical’ to Use GLP-1s Post Surgery

Commenting on the study findings for GI & Hepatology News, Louis Aronne, MD, director of the Comprehensive Weight Control Center at Weill Cornell Medicine in New York City, who was not involved in the study, said, “I think it is perfectly logical to use GLP-1s in patients who have had bariatric surgery.”

In this study, weight loss in those who took GLP-1s was about 12% (from a median BMI of 42 pre-surgery to 36.7 when a GLP-1 was initiated), which is significantly less than average, Aronne noted. “The patients still had Class 2 obesity.”

“Obesity is the same as other metabolic diseases,” he added. “We have to use common sense and good medical judgment when treating patients. If surgery isn’t completely effective and weight loss is inadequate, I would recommend medications.”

Of note, his team has found that lower doses of GLP-1s are required in those who have had surgery than in those who have not. “My opinion is that patients who have undergone bariatric surgery seem to be more sensitive to the medications than the average patient, but this hasn’t been carefully studied.”

To prepare patients for the possible use of GLP1s post-surgery, he suggested telling those with very high BMI that “they may need medication in addition to the procedure in order to get the best result.”

Mehta added, “Ultimately, the decision to start GLP-1s after surgery is shared between patients and clinicians. Given the amount of media coverage on GLP-1 therapies, it is not surprising that more patients are initiating these discussions with their doctors.”

Mehta is supported by the US National Institute on Aging and reported receiving grants from the institute for this study; no other funding was reported. Lauer reported receiving grants from the US National Institutes of Health.

A version of this article first appeared on Medscape.com.

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