Bariatric Surgery Outperforms GLP-1 Drugs in Landmark Heart Risk Analysis

For millions of people living with obesity, the two most powerful tools for protecting the heart have long competed in separate corners: the operating theatre and the pharmacy. Now, one of the largest comparative analyses ever attempted has weighed them against each other, and the result is striking. A systematic review and network meta-analysis published in Health Science Reports pooled data from 43 studies covering 932,380 patients and found that bariatric surgery consistently outperformed glucagon-like peptide-1 receptor agonists, the class of drugs behind semaglutide and liraglutide, in reducing major cardiovascular events. Surgery cut the risk of major adverse cardiovascular events by roughly 34 percent under random-effects models, while the drugs achieved a 15 percent reduction. For heart failure, the gap widened dramatically: surgery reduced risk by about 55 percent, whereas the drug class showed reductions that did not reach statistical significance once the most conservative statistical models were applied.

The stakes of this comparison could hardly be higher. According to the World Obesity Atlas 2023, 38 percent of the global population is currently overweight or living with obesity, a figure projected to climb to 51 percent by 2035. The World Health Organization reports that adult obesity rates have doubled since 1990, while adolescent rates have quadrupled. Obesity is not merely a matter of weight; it is a metabolic engine that drives dyslipidemia, hypertension, sleep apnea and a prothrombotic state, each of which compounds cardiovascular danger. Evidence cited in the analysis shows that individuals with both obesity and diabetes face a 96 percent higher risk of cardiovascular mortality than people of normal weight without diabetes, and obesity alone raises the likelihood of myocardial infarction by approximately 10 percent compared with normal-weight individuals.

Both interventions have individually demonstrated impressive cardiovascular credentials. Previous meta-analytic work summarized in the study indicates that GLP-1 receptor agonists reduce major adverse cardiovascular events by 14 percent, heart failure by 11 percent, myocardial infarction by 10 percent, stroke by 17 percent and cardiovascular mortality by 13 percent. Bariatric surgery, by comparison, has been associated with a 50 percent decrease in heart failure, 42 percent in myocardial infarction, 36 percent in stroke and 41 percent in cardiovascular mortality. What was missing was a rigorous head-to-head verdict, because large randomized trials directly comparing the two approaches simply do not exist. The research team, led by Erfan Shirmohammadi and colleagues, turned to network meta-analysis, a statistical framework that combines direct comparisons, such as surgery versus control, with indirect ones, allowing surgery and drugs to be ranked through their shared comparator.

The methodological architecture of the study is worth appreciating, because its conclusions rest on it. The researchers searched PubMed/MEDLINE, Ovid/Embase, Google Scholar and the Cochrane Library for publications from January 2000 to September 30, 2024, screening 932 records down to 43 included studies reported under PRISMA guidelines. The evidence network contained three nodes: bariatric surgery, GLP-1 receptor agonists and control. Twenty-eight cohort studies supplied the surgical evidence, eleven randomized controlled trials supplied the pharmacological evidence, and four observational cohorts provided direct surgery-versus-drug comparisons. Risk of bias was assessed with the Cochrane Risk of Bias Tool for the randomized trials and the Newcastle-Ottawa Scale for the observational studies, with the surgical cohorts generally rated as good quality and the drug trials as low risk.

The headline numbers come from the random-effects hazard ratio models, which are considered the more conservative reading because they account for variability between studies. Bariatric surgery versus control yielded a hazard ratio of 0.66 for major adverse cardiovascular events, meaning a 34 percent risk reduction, while GLP-1 receptor agonists versus control produced a hazard ratio of 0.85, a 15 percent reduction. For heart failure, surgery achieved a hazard ratio of 0.45, a 55 percent reduction, whereas the drugs showed a non-significant hazard ratio of 0.87. For myocardial infarction, surgery delivered a hazard ratio of 0.53, cutting risk by 47 percent, while the drug class showed a non-significant 0.91. Fixed-effects models told a similar story with somewhat smaller effect sizes, and parallel analyses using risk ratios rather than hazard ratios reproduced the same directional pattern, an internal consistency check the authors describe as validation of their trends.

Because network meta-analysis lives or dies by the coherence of its evidence web, the team ran node-splitting analyses to test whether direct and indirect estimates disagreed. They did not. For major adverse cardiovascular events, the network estimate for surgery versus GLP-1 receptor agonists was 0.54 in the common-effects model, with direct evidence at 0.50 and indirect evidence at 0.56, and the ratio of odds ratios produced p-values ranging from 0.62 to 0.94, far from any threshold of inconsistency. Heart failure showed the same harmony, with inconsistency p-values between 0.42 and 0.60. Funnel plots displayed largely symmetrical distributions, suggesting low likelihood of publication bias. For myocardial infarction, no node-splitting was possible because no direct comparative evidence existed for that outcome, a gap the authors flag as a limit on the precision of that particular indirect estimate.

Why would surgery so decisively outpace a drug class celebrated as one of the great cardiovascular breakthroughs of the decade? The authors point to weight loss-dependent and weight loss-independent mechanisms. Bariatric surgery induces broader and more durable metabolic remodelling: meta-analytic evidence shows it enhances the cholesterol efflux capacity of high-density lipoprotein particles and significantly lowers low-density lipoprotein and lipoprotein(a) concentrations, modifying atherogenic lipoprotein pathways in ways that persist for years. GLP-1 receptor agonists, for their part, exert direct effects on natriuresis, vascular tissue, myocardium and endothelium, but they produce a smaller magnitude of weight loss through sustained pharmacological modulation of metabolic, inflammatory and atherosclerotic pathways. In essence, the scalpel appears to reset the metabolic system more profoundly than the injection fine-tunes it.

The authors are careful, however, to attach substantial caveats to their verdict. The evidence base is fundamentally asymmetric: nearly all surgical data come from observational cohorts, while nearly all drug data come from randomized trials, a design mismatch that can introduce residual confounding into the surgical arm, since patients selected for surgery may differ systematically from those who are not. Heterogeneity across the analyses was moderate to high, with I-squared values reaching 92.5 percent in some risk-ratio models, reflecting variation in follow-up duration, intervention type, baseline diabetes prevalence and obesity severity. The randomized trials included mostly first-generation GLP-1 receptor agonists rather than newer agents such as tirzepatide, and subgroup analyses or meta-regression could not be performed due to data limitations. The absence of large-scale head-to-head randomized trials remains the central constraint on the field.

Those caveats shape, but do not erase, the clinical message. The authors suggest that bariatric surgery may be the preferred intervention for patients with obesity who are surgical candidates and carry high cardiovascular risk, particularly those with established heart failure or prior myocardial infarction. GLP-1 receptor agonists remain an effective and far less invasive alternative for reducing major adverse cardiovascular events when surgery is contraindicated, declined or inaccessible, and the choice between the two should be individualized according to surgical risk, patient preference, comorbidity profile and healthcare access. With obesity projected to encompass half of humanity within a decade, and cardiovascular disease its deadliest shadow, the analysis signals that the next frontier is not choosing a winner but mapping which patient profiles benefit most from which intervention, through trials stratified by surgery type, drug generation, diabetes status and baseline risk.

Subject of Research: Comparative cardiovascular outcomes of bariatric surgery versus GLP-1 receptor agonist therapy in people with obesity

Article Title: Comparative Cardiovascular Outcomes of GLP‐1 Receptor Agonists Versus Bariatric Surgery: A Systematic Review and Network Meta‐Analysis

Article References: Shirmohammadi, E., Ghasemloo, N., Ebrahimi, N., Mohammadzadeh, N., Ehtemami, A., Babaei, M., & Fardoost, S. (2026). Comparative Cardiovascular Outcomes of GLP ‐1 Receptor Agonists Versus Bariatric Surgery: A Systematic Review and Network Meta‐Analysis. Endocrinology, Diabetes & Metabolism, 9(5), Article e70311. https://doi.org/10.1002/edm2.70311

Image Credits: AI Generated

DOI: 10.1002/edm2.70311

Keywords: bariatric surgery, GLP-1 receptor agonists, cardiovascular outcomes, major adverse cardiovascular events, heart failure, myocardial infarction, network meta-analysis, obesity, semaglutide, systematic review, metabolic surgery, cardiovascular risk