Mice Study Suggests Tirzepatide Enhances Metabolism by Activating Brown Fat in Addition to Reducing Weight
Key Takeaways:
- A preclinical mouse study indicates that tirzepatide may improve metabolism not only by reducing appetite, but also by activating brown adipose tissue.
- The research suggests that this activation increases energy expenditure and supports improvements in blood glucose and lipid levels.
- Findings remain preliminary and require confirmation in human studies before clinical conclusions can be drawn.
A closer look at tirzepatide’s metabolic effects
Tirzepatide has transformed the treatment landscape for people living with obesity and for those with poorly controlled type 2 diabetes mellitus. Despite its established clinical benefits, the precise molecular and cellular mechanisms underpinning its effects are not yet fully understood.
A recent study conducted in mice provides new insight into how the drug may influence metabolism beyond its well-recognised impact on body weight. The findings suggest that tirzepatide directly activates brown adipose tissue, a specialised form of fat involved in energy expenditure. According to the researchers, this discovery helps clarify how the drug works and may inform the development of more comprehensive treatments for obesity and related metabolic diseases.
The study was led by Marion Peyrou, Ramón y Cajal researcher at the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona, the Sant Joan de Déu Research Institute and the CIBER in Physiopathology of Obesity and Nutrition.
A dual-action therapy
Tirzepatide, marketed under the name Mounjaro, is approved for weight management in adults living with obesity or with overweight accompanied by comorbidities. It is also indicated for the treatment of inadequately controlled type 2 diabetes.
Unlike earlier anti-obesity medicines, tirzepatide acts simultaneously on two hormonal receptors – glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). This dual mechanism leads to substantial reductions in body weight, primarily through decreased food intake driven by appetite suppression.
However, appetite reduction alone may not explain the full spectrum of its metabolic effects.
Investigating effects on adipose tissue
To better understand how tirzepatide exerts its actions, researchers conducted a detailed analysis of its effects on different fat depots in an experimental mouse model. Such in-depth tissue analysis is not feasible in humans.
In the study, mice were rendered obese through a high-fat diet and then treated with tirzepatide. Their outcomes were compared with a control group of mice that consumed the same quantity of food but did not receive the drug. This design allowed the researchers to distinguish between effects caused directly by the drug and those resulting solely from reduced caloric intake.
The analysis revealed that tirzepatide activates brown adipose tissue. Unlike white adipose tissue, which primarily stores excess energy and accumulates in obesity, brown adipose tissue specialises in burning calories to generate heat.
“This activation is associated with an increased capacity to burn metabolic energy and with the production of batokines by brown adipose tissue, molecules that are beneficial for metabolism,” says Marion Peyrou.
Metabolic benefits beyond appetite suppression
The activation of brown adipose tissue is particularly significant because it indicates that tirzepatide may exert metabolic benefits independent of weight loss due to appetite reduction.
“This drug not only reduces body weight, but also has beneficial effects on metabolism. Active brown adipose tissue ‘burns’ glucose and fat within the body, which would contribute to its positive effect not only in reducing body weight, but also in lowering blood glucose and fat levels, and improving metabolism,” the researcher points out.
By enhancing the body’s ability to utilise both glucose and lipids, activation of brown fat may contribute to improved glycaemic control and lipid profiles in addition to weight reduction.
Implications for obesity treatment strategies
For several years, activation of brown adipose tissue has been viewed as a promising strategy for tackling obesity and metabolic disorders. However, previous pharmacological attempts to stimulate brown fat have frequently been limited by adverse effects, particularly cardiovascular complications.
“Tirzepatide, although it activates brown adipose tissue, does not have these negative effects; on the contrary, it shows cardiovascular benefits. If our findings are confirmed in humans, it would reinforce the importance of developing therapeutic strategies that not only reduce food intake but also increase energy expenditure and brown fat activation,” explains the researcher.
These findings support the broader principle that obesity treatments may be more effective when they target multiple physiological pathways simultaneously. Addressing both energy intake and energy expenditure could offer a more comprehensive approach to weight management and metabolic health.
“This could help improve weight control and reduce associated disorders, such as type 2 diabetes and other metabolic disorders,” she adds.
Towards more personalised prescribing
A deeper understanding of tirzepatide’s mechanisms may also influence how such medicines are prescribed in future.
“Identifying which patient profiles could benefit most, for example those with more compromised energy expenditure, would open the door to more personalized medicine, based not only on appetite or weight control, but also on overall metabolic status,” she emphasizes.
Such an approach could support more tailored treatment strategies for people living with obesity and metabolic disease, taking into account differences in metabolic function rather than focusing solely on body weight.
The need for caution and further research
Despite the promising findings, the researchers emphasise that the results are based on animal data and cannot yet be directly translated into clinical practice.
“As this is a study conducted on mice, we must be cautious, as there may be significant differences between species in terms of metabolism regulation, adipose tissue distribution and response to drugs. Therefore, we need more clinical evidence on the action of these drugs on fat in humans,” concludes Peyrou.
Further human studies will be required to confirm whether the activation of brown adipose tissue observed in mice also occurs in people receiving tirzepatide and whether it meaningfully contributes to its metabolic benefits.
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GPs Offered £3,000 Incentive to Increase Prescribing of NHS Weight Loss Injections
Key Takeaways:
- GP practices in England will be eligible for a £3,000 annual payment for prescribing the maximum number of eligible patients the weight loss drug Mounjaro.
- Access to NHS weight loss injections remains tightly restricted, with eligibility based on BMI and specific health conditions.
- Professional bodies stress that prescribing decisions are driven by clinical judgement, not financial incentives, and warn that workload pressures may increase.
New financial incentives added to GP contract
GP practices across England are set to receive annual incentive payments of £3,000 for prescribing weight loss medication to the maximum number of patients who meet NHS eligibility criteria.
The payments will be incorporated into the national GP contract from April. In addition, practices will be able to receive approximately £1,000 per year for referring patients to weight loss support programmes.
Ministers have said the objective is to ensure that people who could benefit from structured weight management and pharmacological support are able to access it within primary care.
However, specialists in obesity care have cautioned that the overall impact of the scheme may be modest. They note that eligibility for NHS weight loss injections remains tightly restricted and that the incentive does not expand access to a broader population.
Focus on Mounjaro within primary care
The new incentive applies solely to Mounjaro, a next-generation injectable treatment for weight management.
Mounjaro became available on the NHS in 2025. Despite this, prescribing rates in general practice have reportedly been lower than expected, with some variation in uptake across different areas.
Another injectable weight loss medication, Wegovy, is also available through the NHS. However, it is not prescribed by GPs and is instead provided through specialist NHS weight management services.
More than one million people are estimated to be using weight loss injections in the UK. The majority, around nine in ten, are paying privately rather than receiving the medication through the NHS.
Government position: access based on need
The Health Secretary, Wes Streeting, described the medicines as potentially transformative for people living with obesity.
He said: “Weight loss drugs can be a real game changer for those who need them. I’m determined that access should be based on need, not ability to pay.
“Outside the NHS, we’ve seen those who can spare the cash buying privately, and the proliferation of rogue prescribers peddling dangerous unlicensed drugs that are putting patients at risk.
“Investing in general practice will help bring this modern medicine to the many, not just the few, and help shift the focus of the NHS from treatment to prevention.“
The government argues that embedding prescribing targets within the GP contract is consistent with longstanding practice. Incentive payments have previously been used to improve dementia diagnosis rates, increase vaccination uptake, and encourage the prescription of statins to reduce cardiovascular risk.
This marks the first time that weight loss injections have been formally included in the GP contract framework, with the £3,000 payment linked to prescribing the maximum number of eligible patients Mounjaro.
Strict eligibility criteria remain in place
Although the incentive has been introduced, NHS access to Mounjaro remains limited.
During the current financial year, GPs have only been permitted to prescribe the medication to people with severe obesity defined as a body mass index over 40, alongside certain weight-related health conditions.
From next year, eligibility is expected to expand to include people with a BMI over 35. By 2028, it is anticipated that 220,000 patients will be receiving Mounjaro through the NHS. Lower BMI thresholds apply for some ethnic groups.
Despite these planned expansions, the roll-out to date has been described as uneven, with variation between practices and regions.
Support from obesity advocates – with caveats
Katharine Jenner, Director of the Obesity Health Alliance, welcomed the move but emphasised its limitations.
She said: “This doesn’t mean weight loss drugs will suddenly be available to everyone who wants them.
“NHS access will remain very limited and focused on those with the greatest clinical need, and these treatments are most effective when combined with sustained support.“
She also stressed the importance of prevention alongside treatment:
“If we’re serious about moving from sickness to prevention, expanded treatment must go alongside stronger action to improve the food environment and prevent obesity in the first place.“
Her comments reflect a broader concern within public health that medication alone cannot address the structural drivers of obesity.
Concerns about equity and workload
Dr Katie Bramall, representing the British Medical Association, questioned whether the scheme would meaningfully reduce inequalities in access.
She said: “While the headlines promise much, in reality there will be no change to NHS England’s eligibility criteria for patients to access injectable weight-loss medication on the NHS.
“These proposals will do nothing over the next year to address the divide between those able to pay and those left waiting unable to afford private self-funded treatments“
Similarly, Professor Victoria Tzortziou Brown of the Royal College of GPs emphasised that prescribing decisions are rooted in clinical appropriateness rather than financial drivers.
She said: “GPs do not withhold treatment or prescribe based on financial incentives. Decisions are guided by clinical judgement and what is safest and most appropriate for individual patients.
“Widening the roll-out of these medications in general practice could end up increasing workload in a way that may not be sustainable and risk raising unrealistic expectations among patients who may not be eligible or for whom these medicines are not suitable.“
Her comments highlight the tension between expanding pharmacological options in primary care and managing existing workforce pressures.
A cautious step in a tightly controlled rollout
The introduction of incentive payments signals the government’s intention to embed weight loss pharmacotherapy more firmly within general practice. However, strict eligibility criteria remain in place and access is expected to expand gradually over several years.
While the policy aims to increase NHS provision and reduce reliance on private prescribing, professional bodies and advocacy groups have made clear that the immediate effect will be limited. For now, access continues to be targeted at people with the greatest clinical need, with broader prevention strategies still viewed as essential to addressing obesity at population level.
CCH insight:
It is surprising that GPs need incentivising to prescribe GLP-1 medications like Mounjaro – there is undoubtedly a huge need and demand for these drugs. The reluctance to prescribe them is most likely due to the weight bias that still pervades our society and our health system, the view that people shouldn’t need medication to manage their weight. Referring to these drugs as ‘weight loss jabs’ is not helpful – they are anti-obesity medications. Rather than offer a £3k bonus, GPs should be offered training in understanding obesity as a chronic, relapsing disease, and how GLP-1 medications not only support weight loss but can also improve long-term metabolic and cardiovascular health, and in the long run will save billions of pounds by reducing diabetes and heart disease.
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Tirzepatide Not Linked to Increased Depression or Suicidal Ideation in Obesity Trials
Key Takeaways:
- A post hoc analysis of three SURMOUNT trials found no evidence that tirzepatide increases the risk of depression compared with placebo over 72 weeks.
- Rates of suicidal ideation and behaviour were low and similar between tirzepatide and placebo groups, with most reports assessed as low risk.
- Experts emphasise the need for routine mental health assessment in people living with obesity, alongside further research in populations with established psychiatric conditions.
Overview of the analysis
Once-weekly subcutaneous tirzepatide was not associated with an increased risk of depression compared with placebo, according to a post hoc analysis of the SURMOUNT clinical trial programme. The findings were published in Obesity and add to the growing body of evidence examining the psychiatric safety of incretin-based therapies used for weight management.
As previously reported by Healio, in January the Food and Drug Administration requested the removal of warnings related to suicidal ideation and behaviours from the labels of several obesity medications, including liraglutide 3 mg (Saxenda), semaglutide 2.4 mg (Wegovy) and tirzepatide (Zepbound).
In the newly published analysis, researchers reported that adults receiving tirzepatide across three SURMOUNT trials did not experience worsening of depression over the course of the studies.
“The low occurrence of these events with tirzepatide is similar to that observed in pooled analyses of semaglutide 2.4 mg and liraglutide 3 mg, both GLP-1 receptor agonists approved for weight management,” said Thomas A. Wadden, PhD, professor of psychology in psychiatry at the Perelman School of Medicine, University of Pennsylvania, in comments to Healio. “The present report provides the first detailed analysis of the risk of these psychiatric events with tirzepatide.”
Study design and assessment methods
The analysis included data from the SURMOUNT-1, SURMOUNT-2 and SURMOUNT-3 studies. Across all three trials, adults living with obesity or with overweight and at least one weight-related comorbidity were randomly assigned to receive once-weekly subcutaneous tirzepatide or placebo for 72 weeks.
Depression symptoms were evaluated using the Patient Health Questionnaire-9 (PHQ-9). Suicidal ideation and behaviour were assessed using the Columbia-Suicide Severity Rating Scale. In addition, investigators recorded neuropsychiatric adverse events during scheduled study visits.
Depression symptoms over time
A total of 4,056 adults were included in the pooled analysis, of whom 63 percent were women and 74 percent were White. Overall, 2,806 participants received tirzepatide and 1,250 received placebo. At baseline, mean PHQ-9 scores were 2.7 in the tirzepatide group and 2.6 in the placebo group, indicating minimal or no depressive symptoms.
By week 72, participants receiving tirzepatide experienced a 0.6-point greater reduction in PHQ-9 score compared with those receiving placebo.
Among participants who had no or minimal depression symptoms at baseline and received tirzepatide, 79.4 percent remained in that category through the end of safety follow-up. During follow-up, 17 percent reported mild symptoms, 2.9 percent reported moderate symptoms, 0.7 percent reported moderately severe symptoms and 0.1 percent reported severe symptoms.
A smaller proportion of participants in the tirzepatide group moved to a more severe depression category compared with the placebo group, 18.2 percent versus 24.3 percent respectively, with this difference reaching statistical significance (P < .001). Conversely, a higher proportion of those receiving tirzepatide moved to a less severe depression category compared with placebo, 52.4 percent versus 41.8 percent (P < .001).
Suicidal ideation and behaviour
At baseline, a history of suicidal ideation or behaviour was reported by 70 participants receiving tirzepatide and 38 participants receiving placebo. Through the end of safety follow-up, 0.6 percent of participants in both the tirzepatide and placebo groups reported suicidal ideation. Most of these events were classified as low risk.
Moderate-risk suicidal ideation was reported by 0.3 percent of participants receiving tirzepatide and 0.1 percent of those receiving placebo. High-risk suicidal ideation occurred in three participants receiving tirzepatide and one participant receiving placebo.
Suicidal behaviour was reported by two participants in the tirzepatide group and by none in the placebo group.
Treatment-emergent nervous system disorder adverse events occurred in 15.8 percent of participants receiving tirzepatide and 13 percent of those receiving placebo. The investigators reported no difference between groups in the occurrence of treatment-emergent psychiatric disorders overall.
Implications for mental health care in obesity
Wadden noted that he and his colleagues supported the FDA decision to remove warnings related to suicidal ideation and behaviour from the labels of incretin-based obesity medications. However, he stressed that mental health assessment remains essential in the care of people living with obesity.
“Persons with obesity, particularly with a BMI of more than 40 kg/m2, are at substantially increased risk of major depression and anxiety disorders,” Wadden said. “It’s critical that they receive the same mental health care that persons of average weight would when presenting with these conditions.”
He also highlighted the need for further research to better understand the effects of incretin-based therapies in people with established psychiatric conditions.
“Randomized trials of the GLP-1 obesity medications largely excluded persons who, in the past 2 years, had experienced major depression, schizophrenia or bipolar disorder, or who had a lifetime history of suicide attempt,” Wadden said. “GLP-1 medications potentially could be beneficial to individuals who suffer from these conditions. Small, carefully controlled studies would appear warranted, as would a close examination of the FDA’s recent retrospective cohort study of more than 2 million individuals. The FDA’s dataset likely included a far greater range of psychiatric status than found in the randomized controlled trials that evaluated tirzepatide and semaglutide for chronic weight management.”
Disclosures
Wadden reports advising for Novo Nordisk and WW and receiving grants on behalf of the University of Pennsylvania from Eli Lilly, Epitomee Medical and Novo Nordisk. All other relevant financial disclosures are reported in the study.
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Nutrition Gaps Raise Safety Concerns as Use of GLP-1 Weight Loss Drugs Accelerates
Key Takeaways:
- Many people prescribed GLP-1 weight loss medications receive little or no structured nutritional guidance, increasing the risk of preventable vitamin and mineral deficiencies and loss of muscle mass.
- New research highlights a lack of high-quality evidence on how diet quality, protein intake, and micronutrient intake are affected during treatment with drugs such as semaglutide and tirzepatide.
- Experts warn that without integrated nutritional care, the rapid expansion of GLP-1 drug use could undermine long-term health benefits despite effective weight loss.
Experts from University College London and the University of Cambridge are warning that many people prescribed newer weight loss medications may not be receiving sufficient nutritional guidance to support safe and sustainable weight loss. As a result, some individuals may face avoidable risks, including vitamin and mineral deficiencies and loss of lean body mass, particularly muscle.
The concerns arise from new research published in Obesity Reviews. Led by Dr Marie Spreckley of the University of Cambridge, the review identified limited high-quality evidence on how nutritional advice influences calorie intake, body composition, protein consumption, and patient experiences among people using these medications.
How GLP-1 weight loss drugs work
Drugs such as semaglutide and tirzepatide, sold under brand names including Ozempic, Wegovy, and Mounjaro, work by mimicking the action of glucagon-like peptide-1 (GLP-1). This hormone is released after eating and plays a role in regulating appetite and glucose metabolism. By enhancing feelings of fullness, reducing hunger, and dampening food cravings, these medications can substantially lower energy intake.
Studies suggest that calorie intake may fall by 16–39%, helping to explain why these drugs are highly effective for people living with obesity or overweight. However, the researchers note that there has been very little detailed study of how such reductions affect overall diet quality, protein intake, or micronutrient intake, including vitamins and minerals. Existing evidence indicates that lean body mass, including muscle tissue, can account for as much as 40% of total weight lost during treatment.
Experts warn of risks without nutrition support
Dr Adrian Brown, an NIHR Advanced Fellow at UCL’s Centre of Obesity Research and the study’s corresponding author, described how these medications alter eating behaviour.
“Obesity management medications work by suppressing appetite, increasing feelings of fullness, and altering eating behaviors, which often leads people to eat significantly less. This can be highly beneficial for individuals living with obesity, as it supports substantial weight loss and improves health outcomes.
“However, without appropriate nutritional guidance and support from healthcare professionals, there is a real risk that reduced food intake could compromise dietary quality, meaning people may not get enough protein, fiber, vitamins, and minerals essential for maintaining overall health.”
Without structured support, reduced intake may unintentionally lead to inadequate consumption of nutrients needed to preserve muscle mass, bone health, immune function, and overall physical resilience.
Public guidelines versus private use
Guidance from the National Institute for Health and Care Excellence recommends semaglutide for weight management only for people who meet strict eligibility criteria, such as a body mass index of at least 35.0 kg/m² alongside obesity-related comorbidities including type 2 diabetes or cardiovascular disease. When prescribed through the NHS, the medication is intended to be delivered as part of a comprehensive programme that includes dietary changes and increased physical activity.
In reality, most people currently using GLP-1 drugs in the UK obtain them outside the NHS. An estimated 1.5 million people are now using these medications, with around 95% accessing them through private providers. In these settings, ongoing nutritional advice and follow-up support are not always consistently offered.
Rising use outpaces nutrition guidance
Dr Spreckley, who works at the Medical Research Council Epidemiology Unit at the University of Cambridge, said nutritional care has not kept pace with the rapid uptake of these therapies.
“Use of GLP-1 receptor agonist therapies has increased rapidly in a very short period of time, but the nutritional support available to people using these medications has not kept pace. Many people receive little or no structured guidance on diet quality, protein intake, or micronutrient adequacy while experiencing marked appetite suppression.
“If nutritional care is not integrated alongside treatment, there’s a risk of replacing one set of health problems with another, through preventable nutritional deficiencies and largely avoidable loss of muscle mass. This represents a missed opportunity to support long-term health alongside weight loss.”
Low intakes of essential vitamins and minerals are associated with fatigue, impaired immune function, hair loss, and increased risk of osteoporosis. Loss of lean mass, most commonly muscle, can also raise the likelihood of weakness, injuries, and falls, particularly in older adults.
Limited research leaves major questions unanswered
The review identified only 12 studies that examined diet and nutritional outcomes alongside treatment with semaglutide or tirzepatide. These studies differed widely in how dietary advice was delivered and how nutritional outcomes were measured. Many lacked standardised methods and consistent reporting, making it difficult to draw firm conclusions about best practice.
Despite the rapid expansion of GLP-1 drug use, the researchers found little robust evidence to guide clinicians on how to support people nutritionally during treatment.
Lessons from bariatric nutrition care
Given the urgent need for practical guidance, the researchers suggest that interim lessons could be drawn from nutritional care used after bariatric surgery. Procedures such as gastric banding and gastric bypass lead to similar reductions in appetite and food intake.
Dr Cara Ruggiero, a co-author from the MRC Epidemiology Unit at the University of Cambridge, said established post-surgery principles could help address current gaps.
“While GLP-1 receptor agonists are increasingly used, there remains a clear gap in structured nutritional guidance. In the interim, we can draw on well-established post-bariatric nutrition principles. Our previous work highlights the importance of prioritizing nutrient-dense foods including high-quality protein intake, ideally distributed evenly across meals, to help preserve lean mass during periods of reduced appetite and rapid weight loss.”
The available evidence did not support recommending strict low-fat diets alongside GLP-1 therapies. However, some observational studies reported that people using these medications consumed relatively high amounts of total and saturated fat, suggesting a potential need for personalised guidance that aligns with national dietary recommendations.
Meal timing was rarely examined in clinical trials. Nevertheless, the researchers note that eating smaller meals more frequently may help manage side effects such as nausea and improve tolerability, particularly during the early stages of treatment.
Studying real-world experiences
The research team also emphasised the importance of incorporating the perspectives of people using GLP-1 medications into future studies. Understanding what types of information and support individuals find most helpful could improve real-world care and long-term outcomes.
To address this, the team has launched AMPLIFY – Amplifying Meaningful Perspectives and Lived experiences of Incretin therapy use From diverse communitY voices. The project aims to explore how people experience next-generation weight loss medications in everyday life.
“These medications are transforming obesity care, but we know very little about how they shape people’s daily lives, including changes in appetite, eating patterns, well-being, and quality of life,” Dr Spreckley said. “That’s what we’ll explore, working in particular with people from communities historically under-represented in obesity research, to help shape the future of obesity treatment.”
The research was funded by the National Institute for Health and Care Research, with additional support from the Medical Research Council and the NIHR UCLH Biomedical Research Centre.
CCH insights:
GLP-1 medications are licensed for the treatment of diabetes and obesity and they should be used alongside diet and lifestyle advice to improve cardiometabolic health. However, they are now commonly known as ‘weight loss drugs’, implying their primary aim is for people to lose weight. But this is kind of missing the point – the weight loss outcome is one of the mediating effects of the drugs which leads to improved health. However, if weight loss is not accompanied by a move to a healthy diet, which provides adequate levels of essential nutrients, then health outcomes will be compromised, as highlighted by this study.
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GLP-1 Receptor Agonists Linked to Lower Mortality After Diabetic Foot Ulcers, Nationwide French Study Finds
Key Takeaways:
- Nearly one in seven people experienced death within one year of a first diabetic foot ulcer, highlighting the severity of risk following ulcer onset.
- Treatment with GLP-1 receptor agonists was independently associated with improved survival, including after major lower-limb amputation.
- Multidisciplinary care and early specialist involvement were associated with better outcomes, reinforcing the importance of structured follow-up.
Background and study aims
Diabetic foot ulcers remain one of the most serious complications of diabetes, often signalling advanced disease and a high burden of comorbidity. Despite advances in diabetes care, mortality following a first diabetic foot ulcer continues to be substantial.
This nationwide observational study set out to identify factors associated with one-year mortality after a first recorded diabetic foot ulcer using data from the French National Health Data System (SNDS). A secondary objective was to examine mortality within one year following major lower-limb amputation in the same population.
Study design and data sources
Researchers conducted a retrospective cohort analysis using the SNDS, a comprehensive national database that captures hospital admissions, outpatient care, prescribed medications, and long-term disease registrations across France.
Adults with a first incident diabetic foot ulcer recorded between January 2017 and December 2018 were included. Case identification combined hospital discharge diagnoses and community care records, allowing capture of people diagnosed both in hospital and in outpatient settings. All individuals were followed for 12 months after ulcer identification.
To examine associations with mortality, the researchers used Cox proportional hazards models. These models adjusted for a wide range of variables, including demographic characteristics, clinical comorbidities, diabetes treatments, major amputation, and access to specialist care.
Mortality and amputation outcomes
In total, 133,791 people with a first diabetic foot ulcer were identified. Within one year of diagnosis, 14.6% died, underlining the high short-term mortality associated with this complication. During the same period, 3.5% underwent a major lower-limb amputation.
Outcomes following amputation were particularly poor. Among those who had a major amputation, 28.8% died within one year, indicating a markedly elevated risk compared with people who did not undergo amputation.
Factors associated with increased mortality
Several factors were independently associated with a higher risk of death within one year of a first diabetic foot ulcer. These included male sex, increasing age, and ulcers identified during a hospital admission rather than in the community.
Clinical and treatment-related predictors of higher mortality included insulin use, major lower-limb amputation, and a range of comorbid conditions. Cardiovascular disease, cancer, dementia, end-stage kidney disease, and liver disease were all strongly associated with poorer survival.
Similar patterns were observed when analysing mortality after major amputation, suggesting that underlying health status and disease severity play a central role in outcomes across the care pathway.
Protective factors and the role of GLP-1 receptor agonists
Several factors were associated with a lower risk of death. Use of lipid-lowering therapy emerged as a protective factor, as did prior contact with specialist healthcare professionals. People who had consulted diabetologists, ophthalmologists, or podiatrists before ulcer onset experienced better survival, pointing to the benefits of ongoing, multidisciplinary diabetes care.
Notably, treatment with glucagon-like peptide-1 receptor agonists was independently associated with reduced mortality at one year. This association persisted both in the overall cohort and among people who underwent major lower-limb amputation, suggesting a consistent survival benefit linked to this class of medication.
Interpretation and implications for care
The findings confirm that one-year mortality after a diabetic foot ulcer remains unacceptably high and is closely linked to age, comorbidity burden, and disease severity. Importantly, the inclusion of community-identified ulcers highlights that people with diabetic foot disease are highly vulnerable even outside hospital settings.
The observed association between GLP-1 receptor agonist use and improved survival adds to growing evidence that these therapies may offer benefits beyond glycaemic control. Alongside pharmacological treatment, structured follow-up and early involvement of specialist services appear to play a critical role in improving outcomes.
Conclusions
This nationwide study shows that mortality following a first diabetic foot ulcer is substantial, particularly among people with advanced comorbidities and those requiring major amputation. Glucagon-like peptide-1 receptor agonists and coordinated, multidisciplinary care were associated with better survival and should be prioritised in high-risk populations.
Together, these findings underscore the urgent need to strengthen preventive strategies, optimise care pathways, and ensure timely access to specialist diabetes and foot care services for people living with diabetes who are at risk of ulceration.
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Combination of Hormone Therapy and Tirzepatide Linked to Greater Weight Loss After Menopause, Study Finds
Key Takeaways:
- Postmenopausal women using menopausal hormone therapy alongside tirzepatide lost around 35% more weight than those using tirzepatide alone in an observational study.
- The findings suggest a potential interaction between hormone therapy and GLP-1-based obesity medications, although causality cannot be confirmed.
- Researchers say the results warrant randomised clinical trials to explore mechanisms and broader cardiometabolic effects.
Weight management challenges after menopause
A new study led by researchers at Mayo Clinic suggests that combining menopausal hormone therapy with tirzepatide may be associated with substantially greater weight loss in postmenopausal women. The findings, published in The Lancet Obstetrics, Gynaecology, & Women’s Health, indicate that women receiving hormone therapy lost around 35% more weight while taking tirzepatide compared with those treated with tirzepatide alone.
Tirzepatide is approved by the US Food and Drug Administration for the treatment of overweight and obesity. The study’s authors say the results could expand treatment options for the many women who experience weight gain and related health risks following menopause.
Menopause is associated with accelerated age-related weight gain and a higher likelihood of developing overweight or obesity, both of which are major risk factors for cardiovascular disease, type 2 diabetes, and other long-term conditions. In addition to changes in body weight, the decline in oestrogen levels that occurs during menopause is also linked to physiological changes that may independently increase cardiovascular risk.
“This study provides important insights for developing more effective and personalized strategies for managing cardiometabolic risk in postmenopausal women,” says Regina Castaneda, MD, postdoctoral research fellow at Mayo Clinic and first author of the study.
Hormone therapy and obesity treatments
Menopausal hormone therapy is considered the most effective first-line treatment for common menopausal symptoms, such as hot flashes and night sweats, which affect up to 75% of postmenopausal women. Despite its widespread use, evidence on how hormone therapy may interact with pharmacological obesity treatments remains limited.
Previous research has suggested that postmenopausal women using hormone therapy may experience greater weight loss when treated with semaglutide, another GLP-1-based medication for obesity. However, until now, no studies had specifically examined whether hormone therapy might influence outcomes in people treated with tirzepatide.
To explore this question, Dr Castaneda and colleagues reviewed data from 120 participants with overweight or obesity who had received tirzepatide for weight management for at least 12 months. Outcomes among participants who were also using menopausal hormone therapy were compared with those of participants with similar characteristics who were not receiving hormone therapy.
Findings and limitations
According to the researchers, women using both treatments experienced markedly greater weight loss than those using tirzepatide alone.
“In this observational study, women who used menopausal hormone therapy lost about 35% more weight than women taking tirzepatide alone. Because this was not a randomized trial, we cannot say hormone therapy caused additional weight loss,” says Maria Daniela Hurtado Andrade, MD, PhD, endocrinologist at Mayo Clinic and senior author of the study.
She adds that other factors may partly explain the difference observed between the groups.
“It is possible that women using hormone therapy were already engaged in healthier behaviors, or that menopause symptom relief improved sleep and quality of life, making it easier to stay engaged with dietary and physical activity changes.”
The authors emphasise that, as an observational analysis, the study cannot establish a causal relationship between hormone therapy and enhanced weight loss. Nonetheless, they argue that the size of the observed difference is clinically meaningful.
Possible biological synergy
Dr Castaneda notes that the findings align with emerging preclinical evidence suggesting a biological interaction between oestrogen and GLP-1-based therapies.
“The magnitude of this difference warrants future studies that could help clarify how GLP-1-based obesity medications and menopausal hormone therapy may interact. Interestingly, preclinical data suggest a potential synergy, with estrogen appearing to enhance the appetite-suppressing effects of GLP-1,” she says.
Such a mechanism could help explain why women receiving hormone therapy appeared to derive additional benefit from tirzepatide in this study.
Next steps for research
The research team plans to build on these findings through more rigorous study designs.
“Next, we plan to test these observations in a randomized clinical trial and determine if benefits extend beyond weight loss – specifically, whether hormone therapy also enhances the effects of these medications on cardiometabolic measures,” says Dr Hurtado Andrade. “If confirmed, this work could speed the development and adoption of new, evidence-based strategies to reduce this risk for millions of postmenopausal women navigating this life stage.”
The study was funded by the Mayo Clinic Center for Women’s Health Research. The full publication includes a complete list of authors, disclosures, and funding sources.
CCH insight:
This is an interesting study, but as the authors state, no conclusions can be drawn from the findings. But it does raise many questions about the possible potential synergistic effects of oestrogen and GLP-1 therapy. Establishing whether cardiometabolic benefits of GLP-1 medications are amplified, as well as weight loss, should be a priority.
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More Than One in Four Adults Worldwide May Be Eligible for GLP-1 Weight-Loss Medicines, Global Analysis Suggests
Key Takeaways:
- More than 27 percent of adults globally may be eligible for GLP-1 receptor agonists for weight management, based on pooled data from 99 countries.
- Eligibility is highest among women, older adults, and people living in low- and middle-income countries, raising significant questions around access and health equity.
- Researchers emphasise that medicines alone are not sufficient, and sustained investment in prevention and non-pharmacological obesity care remains essential.
A growing global obesity challenge
The worldwide prevalence of obesity has more than doubled over the past three decades, accompanied by sharp rises in weight-related conditions such as type 2 diabetes, cardiovascular disease, and several cancers. This escalating public health challenge places increasing strain on healthcare systems and national economies across the globe.
Against this backdrop, a new international study suggests that glucagon-like peptide-1 receptor agonists, commonly referred to as GLP-1 medications, could play a substantial role in addressing obesity and its related complications at scale. The analysis was co-led by investigators from Mass General Brigham and aimed to estimate how many adults worldwide might benefit from these medicines.
Large-scale global data analysis
Researchers from Mass General Brigham collaborated with colleagues at Washington University School of Medicine in St. Louis and Emory University’s Rollins School of Public Health to pool household health survey data from 99 countries, collected between 2008 and 2021.
The final dataset included 810,635 adults aged 25 to 64 years, selected based on the availability of key clinical measures, including:
- Body mass index
- Blood pressure
- Diabetes biomarkers
- Diagnostic history of hypertension and diabetes
Eligibility for GLP-1 treatment was defined using established clinical thresholds. Adults were considered eligible if they had:
- A BMI greater than 30, or
- A BMI greater than 27 in the presence of hypertension, diabetes, or both
One in four adults eligible worldwide
Using these criteria, the researchers found that 27 percent of adults globally would be eligible for GLP-1 medications for weight management. Notably, around four-fifths of eligible individuals lived in low- and middle-income countries, highlighting a potential mismatch between need and access.
Eligibility varied substantially by region:
- Europe and North America showed the highest rates at 42.8 percent
- The Pacific Islands followed closely at 41.0 percent
Differences were also observed across demographic groups:
- Women were more likely to be eligible than men, at 28.5 percent versus lower rates among men
- Older adults showed markedly higher eligibility at 38.3 percent, compared with 17.9 percent among younger adults
The findings were published as a research letter in The Lancet Diabetes & Endocrinology.
Rethinking obesity through biology
Commenting on the findings, co-senior author Jennifer Manne-Goehler, MD, ScD, a physician at Brigham and Women’s Hospital and Mass General Brigham, highlighted the paradigm shift represented by GLP-1 therapies.
“There has never been such a potentially transformational and scalable tool for obesity, type 2 diabetes, and other health-related complications of obesity.”
She also reflected on the historical framing of obesity as a personal failing rather than a biologically driven disease.
“For so many decades, we told everyone the problem was you – you need to move more and eat less, then you will not struggle with this problem. GLP-1 receptor agonists have allowed us to really understand that biology is much more powerful than that, and ‘eat less, move more’ is just an oversimplified way to think about things.”
Global interest meets practical constraints
The potential of GLP-1 medicines has already been recognised by the World Health Organization, which is actively exploring ways to make these treatments more widely available as standard therapies. However, translating this promise into real-world impact depends on understanding the scale of need and addressing significant barriers to access.
Corresponding author Sang Gune K. Yoo, MD, who conducted the work while a research fellow in cardiology at Washington University School of Medicine, noted that the findings were consistent with global obesity trends.
“Given the steadily increasing prevalence of obesity, it is not surprising that our analysis found that more than one quarter of adults around the world may be eligible for this medication.”
He cautioned, however, that important questions remain unanswered.
“This medication has the potential to help many individuals, although further research is needed to better understand its long-term safety and sustainability. Access remains a major challenge as these medications are difficult to obtain in many settings. Most importantly, we must continue to invest in and develop effective non-pharmacological strategies for the prevention and treatment of obesity, an area where substantial gaps remain.”
Equity at the centre of global implementation
The study also underscores profound equity considerations. Eligibility was disproportionately high among women and people living in regions with limited healthcare resources.
Manne-Goehler highlighted the urgency of addressing these disparities.
“These socioeconomic and gender eligibility percentiles are especially staggering. As of last year, type 2 diabetes was the top cause of death for women in South Africa. There are parts of the world where women can really benefit from these medicines, and it is our job to see through their implementation.”
Co-lead author Felix Teufel, MD, from Emory University’s Rollins School of Public Health, framed access to GLP-1 therapies as a broader ethical issue.
“Global access to GLP-1s is a question of health equity. The goal is to ensure large-scale access for people who would benefit most – not just those easiest to reach.”
Beyond medicines alone
While the findings point to a potentially transformative role for GLP-1 medications in global obesity care, the authors stress that pharmacological approaches cannot replace comprehensive prevention and treatment strategies. Addressing obesity at scale will continue to require sustained investment in public health, supportive environments, and evidence-based, non-pharmacological interventions alongside new medical therapies.
CCH insight:
This study reminds us of the scale of the obesity pandemic. There are more than 1 billion people estimated to be living with obesity, according to the World Health Organisation – most of whom could in theory benefit from GLP-1 medications. The priority should be to provide access for those who are in greatest need, rather than those who can afford to pay for them. The development of oral GLP-1s is a big step, as this will increase access and bring prices down, but there is a very long way to go.
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GLP-1 Weight-Loss Medications Linked to Fewer Severe Asthma Attacks in Adolescents with Excess Weight
Key Takeaways:
- Adolescents with excess weight and asthma who were prescribed GLP-1 medications experienced around half as many asthma-related emergency room visits over one year compared with peers not taking these drugs.
- Use of GLP-1 therapies was also associated with reduced reliance on steroids and rescue inhalers, suggesting improved asthma control.
- Researchers suggest these medicines may offer a dual benefit, supporting weight management while lowering the risk of asthma exacerbations in this population.
Study suggests dual benefit for weight and asthma control
Severe asthma attacks among adolescents with excess weight may be significantly reduced with the use of newer weight-loss medications such as Ozempic and Zepbound, according to a new observational study.
The research found that emergency room visits for asthma were cut by more than half among teenagers who were prescribed a glucagon-like peptide-1 (GLP-1) receptor agonist. The findings were reported on 29 December in JAMA Network Open.
“Our findings suggest a potential dual benefit for this population, where a single class of medication could address both weight management and lower risk for asthma exacerbation, thereby potentially reducing the burden of two common and interconnected chronic conditions,” the researchers concluded.
The study was led by Dr Lin‑Shien Fu, chief of paediatric nephrology and immunology at Taichung Veterans General Hospital.
How the study was conducted
Researchers followed 1,070 adolescents aged 12 to 18 years who were living with excess weight and had a clinical diagnosis of asthma. Approximately half of the group had been prescribed a GLP-1 medication, while the remainder had not received a weight-loss drug.
GLP-1 receptor agonists mimic the naturally occurring GLP-1 hormone, which plays a role in regulating insulin and blood glucose levels. These medicines also reduce appetite and slow gastric emptying, contributing to weight loss.
Over a 12-month follow-up period, the researchers recorded:
- Eight asthma-related emergency department visits among adolescents taking a GLP-1 medication
- Nineteen asthma-related emergency visits among those not prescribed a weight-loss drug
Reduced need for asthma medications
In addition to fewer emergency visits, adolescents taking GLP-1 medications were less likely to require other treatments for asthma control.
The study found that:
- 21% of adolescents taking a GLP-1 medication required steroid treatment for asthma, compared with 31% of those not taking the drugs
- 32% of adolescents in the GLP-1 group needed a rescue inhaler, compared with 45% in the non-GLP-1 group
These differences suggest an overall reduction in asthma severity and symptom burden among those prescribed GLP-1 therapies.
Weight loss and inflammation may explain the findings
Experts not involved in the research say the observed improvements are likely linked to the degree of weight loss achieved with these newer medications.
Dr Michelle Katzow, medical director of the POWER Kids Weight Management Program and associate professor of paediatrics at Cohen Children’s Medical Center in New York City, commented on the findings in a news release.
“I think it is not surprising and not so new, except for the degree of weight loss that the drug induces is so much bigger in magnitude than we have seen before,” she said.
Dr Katzow explained that excess weight contributes to systemic inflammation, which can worsen asthma symptoms and increase the likelihood of exacerbations.
“The sort of inflammation associated with obesity predisposes somebody to having worse asthma or worse symptoms of asthma,” she said.
“If you can help people lose enough weight by whatever means, then you can improve their asthma severity.”
Implications for adolescents struggling with appetite control
Dr Katzow added that GLP-1 medications may be particularly helpful for adolescents who struggle to adopt healthy behaviours because of persistent hunger.
She noted that this is a common challenge among young people with excess weight.
“And that is true for a lot of kids,” she said. “They are just really hungry and they are thinking about food a lot. Trying to make healthier choices or eat less is really hard to do if you are hungry all the time.”
A cautious but promising signal
While the study does not establish a direct causal relationship, it adds to growing evidence that weight-loss interventions can have meaningful benefits beyond body weight alone. The findings suggest that, for some adolescents living with excess weight and asthma, GLP-1 receptor agonists may help reduce the frequency and severity of asthma exacerbations alongside supporting weight management.
Further research will be needed to confirm these findings and to better understand the long-term safety and clinical role of GLP-1 therapies in paediatric populations.
CCH insight:
The long list of benefits of GLP-1 therapy continues to grow. If obesity increases the risk of asthma, it is not surprising that GLP-1 therapy results in a reduction in hospital visits due to asthma. Further studies are needed to back up these results, and also to see if the same benefits are seen in adults, as well as adolescents.
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GLP-1 Receptor Agonists Unlikely to Meaningfully Influence Obesity-Related Cancer Risk, Review Suggests
Key Takeaways:
- Evidence from randomised trials suggests GLP-1 receptor agonists are unlikely to meaningfully increase or reduce the risk of most obesity-related cancers.
- For several cancer types, including colorectal, liver and endometrial cancer, the certainty of evidence remains low due to limited follow-up.
- Researchers emphasise the need for longer-term studies with cancer-specific outcomes to fully understand potential risks or protective effects.
A comprehensive systematic review published online on 8 December in Annals of Internal Medicine suggests that glucagon-like peptide-1 receptor agonists, commonly known as GLP-1 RAs, have little or no effect on the risk of developing cancers associated with obesity.
The review was led by Albert Ko, MD, of the Harvard T.H. Chan School of Public Health in Boston, and examined data from randomised, placebo-controlled trials involving people treated with GLP-1 RAs for type 2 diabetes or overweight and obesity. While these medications have transformed metabolic care in recent years, concerns have persisted about their long-term safety, including potential cancer risk.
Scope and purpose of the review
GLP-1 receptor agonists are widely prescribed for glycaemic control and weight management, yet their association with cancer has remained uncertain. To address this gap, the researchers conducted a systematic review and meta-analysis to assess whether treatment with GLP-1 RAs is associated with an increased or reduced risk of obesity-related cancers.
The review focused on cancers known to have strong links with excess adiposity, including thyroid, pancreatic, colorectal, gastric, oesophageal, liver, gallbladder, breast, ovarian, endometrial and kidney cancers. It also included multiple myeloma and meningioma.
Data sources and study selection
The authors searched PubMed, Embase, Web of Science, Scopus and the Cochrane Central Register of Controlled Trials from database inception through to August 2025. Only randomised, placebo-controlled trials reporting at least one of the specified cancer outcomes were eligible for inclusion.
In total, 48 trials met the inclusion criteria, encompassing 94,245 participants. None of the trials had been specifically designed to evaluate cancer outcomes, and follow-up durations were generally short.
Methods and quality assessment
Risk of bias across the included trials was assessed using the Cochrane Risk of Bias 2 tool. The certainty of evidence for each outcome was evaluated using the GRADE framework, which considers factors such as study limitations, consistency of results and precision of estimates.
Pooled odds ratios were calculated using random-effects meta-analysis to account for variation between studies.
Main findings by cancer type
The analysis found that GLP-1 receptor agonists probably have little or no effect on the risk of several common obesity-related cancers, based on evidence of moderate certainty.
Specifically:
- Thyroid cancer showed no clear association with GLP-1 RA use, with an odds ratio of 1.37 (95% CI, 0.82 to 2.31), corresponding to between one fewer and nine more cases per 10,000 people treated.
- Pancreatic cancer risk was similarly unaffected, with an odds ratio of 0.84 (95% CI, 0.53 to 1.35), equating to nine fewer to six more cases per 10,000 people.
- Breast cancer showed an odds ratio of 0.95 (95% CI, 0.60 to 1.49), indicating no meaningful difference in risk.
- Kidney cancer also demonstrated no significant association, with an odds ratio of 1.12 (95% CI, 0.78 to 1.60).
For other cancers, including colorectal, oesophageal, liver, gallbladder, ovarian and endometrial cancer, as well as multiple myeloma and meningioma, the evidence suggested little or no effect. However, the certainty of this evidence was rated as low.
For gastric cancer, the findings were described as very uncertain, reflecting sparse data and wide confidence intervals.
Consistency across analyses
The results remained consistent across multiple sensitivity and subgroup analyses. These included analyses restricted to trials with a low risk of bias, studies involving newer agents such as semaglutide or tirzepatide, and comparisons across different follow-up durations, populations, GLP-1 RA classes, doses, weight-loss profiles and durations of action.
This consistency strengthens confidence that the observed lack of association is not driven by a specific drug, dose or patient group.
Limitations of the evidence
The authors highlight important limitations that temper the conclusions. Most notably, the included trials were not designed to detect cancer outcomes and generally had relatively short follow-up periods. As a result, rare cancers or effects that emerge only after prolonged exposure may not have been captured.
Implications and next steps
Summarising the findings, the authors conclude that GLP-1 receptor agonists “may have little or no effect on risk for obesity-related cancers,” while emphasising the need for further research. As they write, “These findings offer important insights into the safety of GLP-1 RAs but highlight the need for longer-term studies with cancer-specific end points to clarify potential risks or protective effects.”
For clinicians and people considering or already using GLP-1 receptor agonists, the review provides a degree of reassurance regarding cancer risk in the short to medium term. However, ongoing surveillance and dedicated long-term studies will be essential as use of these medications continues to expand globally.
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Metabolic Bariatric Surgery Shows Greater Two-Year Weight Loss Than GLP-1 RAs
Key Takeaways:
- Metabolic bariatric surgery was associated with substantially greater and more durable weight loss over two years than treatment with GLP-1 receptor agonists in adults living with class II or III obesity.
- Overall health care costs over two years were lower for people who underwent surgery, largely due to the ongoing pharmacy costs associated with GLP-1 receptor agonist therapy.
- The findings underline the importance of multidisciplinary care, particularly for clinicians managing obesity-related conditions where sustained weight reduction is central to disease control.
Overview
A large retrospective, claims-based cohort study has found that metabolic bariatric surgery delivers greater long-term weight loss benefits and lower overall health care costs over two years compared with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in adults living with severe obesity. The analysis suggests that, in real-world clinical practice, surgical approaches may offer more durable outcomes than pharmacotherapy alone for this population.
Study design and data sources
This retrospective cohort study compared outcomes following metabolic bariatric surgery with those achieved using GLP-1 receptor agonist therapy for weight management. Surgical procedures included sleeve gastrectomy and gastric bypass. Pharmacological treatments included dulaglutide, exenatide, liraglutide, lixisenatide, semaglutide, and tirzepatide.
The analysis drew on data from the Highmark Health insurance claims database linked with electronic health records from the Allegheny Health Network. In total, 30,458 adults living with class II or III obesity were included. All individuals in the weight-loss analysis had a body mass index of at least 40 at the time of enrolment.
To minimise baseline differences between groups, the researchers used propensity score weighting to balance key characteristics, including body mass index, age, sex, comorbid conditions, and patterns of health care utilisation. Adjusted analyses then compared weight-loss trajectories, obesity-related comorbidities, and total health care costs over a two-year follow-up period.
Weight loss outcomes and durability
Of the total cohort, 14,101 people underwent metabolic bariatric surgery, with a mean follow-up of 34 months. A further 16,357 people were prescribed GLP-1 receptor agonists, with a mean follow-up of 32 months.
After two years, metabolic bariatric surgery was associated with markedly greater mean total weight loss than GLP-1 receptor agonist therapy, at 28.3 per cent compared with 10.3 per cent. Weight loss following surgery was also more durable. Ninety-six per cent of people in the surgical group achieved sustained weight loss of at least 10 per cent, compared with 46 per cent of those treated with GLP-1 receptor agonists.
In addition to superior weight outcomes, people who underwent metabolic surgery experienced fewer obesity-related comorbidities and lower health care utilisation across inpatient, outpatient, and emergency care settings.
Cost analysis
Over the two-year follow-up period, metabolic bariatric surgery was associated with significantly lower mean total health care costs than GLP-1 receptor agonist therapy. Average costs were reported as $51,794 for the surgical group compared with $63,483 for those receiving GLP-1 receptor agonists.
The higher costs observed in the pharmacotherapy group were largely driven by ongoing pharmacy expenses related to long-term GLP-1 receptor agonist use. While surgery involves a higher upfront cost, the findings suggest this is offset over time by reduced medication use and lower overall health care utilisation.
Study limitations
The authors note several important limitations. Weight data were available for only a small proportion of participants, comprising 9 per cent of the surgery group and 1.6 per cent of the GLP-1 receptor agonist group. This limits the generalisability of the weight-loss findings to the full cohort.
In addition, the indication for GLP-1 receptor agonist prescriptions was not always clear, meaning some individuals may have been treated primarily for diabetes rather than obesity. However, an obesity-only subgroup analysis restricted to people without a diabetes diagnosis produced similar results, supporting the robustness of the main findings.
Follow-up duration differed slightly between groups, and adherence to GLP-1 receptor agonist therapy was likely lower in this real-world setting than would be expected in a controlled clinical trial. Finally, the cost data reflect the United States health care system and may not be directly transferable to other countries or funding models.
Clinical relevance
For clinicians managing obesity-related complications, including ophthalmologists caring for people with obesity-associated eye disease such as idiopathic intracranial hypertension, these findings highlight the broader systemic benefits of durable weight reduction. Although GLP-1 receptor agonists are increasingly recommended in the management of idiopathic intracranial hypertension, the study suggests that metabolic bariatric surgery may offer greater sustained weight loss at a lower long-term cost.
The results emphasise the value of close collaboration between ophthalmology, endocrinology, and bariatric surgery teams when supporting people whose disease burden is driven by obesity. While ongoing government discussions around medication pricing may influence future cost-effectiveness analyses, the substantial differences observed in this study indicate that metabolic surgery is likely to remain a cost-effective intervention even if GLP-1 receptor agonist costs were to decrease.
Disclosures and publication details
Financial disclosures: Dr Chantal Boisvert reports a financial relationship with Viridian Therapeutics, serving as a consultant or advisor and receiving grant support.
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Manchester Launches Landmark Five-Year Mounjaro Trial to Assess Real-World Outcomes
Key Takeaways:
- A five-year real-world trial in Greater Manchester will evaluate the long-term health, employment, and quality-of-life effects of the anti-obesity medication tirzepatide.
- Up to 3,000 people will participate, with recruitment taking place through GP practices to reflect everyday clinical conditions.
- The study is part of a £279 million partnership between Eli Lilly and the UK government aimed at addressing obesity and improving population health.
Introduction: A major real-world test of tirzepatide
A five-year clinical study has begun in Greater Manchester to examine the real-world effectiveness of the anti-obesity medication tirzepatide, marketed in the United Kingdom as Mounjaro. The trial aims to understand how the treatment affects long-term health outcomes when delivered through primary care. The first participants have now been enrolled after visiting their GP, marking the formal start of the project.
Scope and scale of the trial
Up to 3,000 people are expected to take part in what is described as a first-of-its-kind real-world study. The trial forms part of a broader £279 million initiative jointly developed by US pharmaceutical company Eli Lilly and the UK government. The aim is to evaluate new ways of addressing major public health challenges, including obesity and related long-term conditions.
Professor Martin Rutter, professor of cardiometabolic medicine at the University of Manchester, emphasised the focus on early intervention. He explained that the research will assess “how effective early intervention is in tackling obesity”, and will examine a wide range of clinical and social outcomes.
What is tirzepatide?
Tirzepatide is an injectable medication that works by mimicking a hormone that helps people feel fuller for longer, thereby suppressing appetite. While marketed as Mounjaro in the UK, it is sold under the brand name Zepbound in the United States.
Clinical trials have previously shown that people receiving Mounjaro experienced up to 20 percent weight loss after 72 weeks of treatment. The Greater Manchester study will build on this evidence by measuring how the medication performs in routine practice rather than controlled trial conditions.
Real-world outcomes beyond weight
A distinctive feature of the trial is its focus on long-term and practical indicators of wellbeing. Researchers will assess health metrics but will also study broader outcomes such as employment status, sick-day absences, and quality of life. These measures are particularly relevant given the significant economic and social impact of obesity.
According to Health Secretary Wes Streeting, illnesses linked to obesity currently cost the NHS £11 billion annually. In Greater Manchester alone, approximately 600,000 adults live with obesity, said Mark Fisher, chief executive officer of the NHS Greater Manchester Integrated Care Board.
A 2023 report by Health Innovation Manchester also estimated that obesity costs the region more than £3 billion each year when NHS treatment, social care, and the impact on quality of life are taken into account.
Role of primary care in the study
The trial is major in part because it is being delivered through GP practices, providing insights into how tirzepatide performs when prescribed in everyday settings. Dr Imran Ghafoor, GP Partner at Peterloo Medical Centre in Middleton, highlighted the importance of local trust and accessibility. He stated that patients see their GP practice as a “familiar and accessible space”, adding that the research will help “test solutions tailored to real lives”.
A diverse participant group
Professor Rutter, who also serves as the trial’s chief investigator, noted that the study intends to evaluate the medication’s health effects “in a diverse group of individuals”. This emphasis on diversity aims to ensure that the findings reflect the varied experiences of people living with obesity across the region.
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WHO Warns of Severe Global Shortages of GLP-1 Obesity Medicines as Demand Surges
Key Takeaways:
- Fewer than one in ten people worldwide who could benefit from GLP-1 medicines such as Wegovy and Mounjaro are currently able to access them, due to major limitations in production, affordability, and health system readiness.
- The World Health Organization has issued its first formal guidance on the clinical use of GLP-1 therapies, describing them as “a new chapter” in the treatment of obesity, but emphasising the need for equitable access and comprehensive lifestyle support.
- Without urgent action, global obesity prevalence is projected to double to two billion people by 2030, with associated economic costs reaching three trillion US dollars.
WHO Issues first guidance on GLP-1 medicines amid severe supply constraints
The World Health Organization has warned that fewer than one in ten people globally who could benefit from modern GLP-1 obesity medicines are currently able to obtain them, despite the scale of the obesity epidemic and the transformative clinical potential of drugs such as Wegovy and Mounjaro.
With more than one billion people worldwide now living with obesity, the WHO has called for far more widespread, affordable, and equitable access to GLP-1 therapies. Projections indicate that more than two billion people will be living with obesity by 2030 unless governments implement decisive action. The economic burden is expected to rise steeply, with global costs anticipated to reach three trillion US dollars by the same date.
Dr Tedros Adhanom Ghebreyesus, WHO Director-General, stressed that modern pharmacological treatments must be understood as part of a long-term care approach. He stated: “Our new guidance recognises that obesity is a chronic disease that can be treated with comprehensive and lifelong care. While medication alone will not solve this global health crisis, GLP-1 therapies can help millions overcome obesity and reduce its associated harms.”
The WHO has already added GLP-1 medicines to its essential medicines list for people who are overweight and living with diabetes, signalling that countries are advised to provide access to them. The organisation’s new guidance, described as a “special communication” aimed at clinicians, sets out for the first time its formal position on the value, limitations, and safe use of these drugs.
A new chapter in obesity treatment
The WHO notes that GLP-1 therapies represent “more than a scientific breakthrough”. They mark a decisive shift in how obesity is conceptualised, moving away from viewing it solely as a “lifestyle condition” and towards recognising it as a complex, preventable, and treatable chronic disease. The statement published in the Journal of the American Medical Association asserted: “GLP-1 therapies … have emerged as an important innovation in addressing the global obesity challenge. The advent of these medications represents a tipping point in the treatment of obesity, its complications and related co-morbidities.”
The WHO highlighted increasing evidence that GLP-1 therapies may also reduce the risk of several serious conditions, including heart attacks, strokes, type 2 diabetes, high blood pressure, elevated cholesterol, sleep apnoea, and kidney and arterial disease.
However, the organisation emphasised that these medicines must always be paired with holistic support. Individuals prescribed GLP-1s should receive advice on nutrition, physical activity, and behavioural counselling to maintain weight loss and improve long-term health outcomes. The WHO also reiterated that pregnant women should not use GLP-1 therapies.
Global access limited by production, affordability, and system capacity
Despite rising demand, global production capacity remains a major barrier. The WHO estimates that even under the most optimistic forecasts, manufacturers could produce enough GLP-1 medicines for only about 100 million people. This represents less than 10 per cent of the more than one billion who could benefit.
High prices, limited manufacturing capability, and supply chain constraints all significantly restrict access. The WHO has urged pharmaceutical companies to expand production rapidly and to reduce the prices of medications such as Mounjaro and Ozempic to prevent people in low-income countries from being excluded.
The guideline calls for measures such as voluntary licensing, through which patent-holding companies allow other manufacturers to produce low-cost generic versions. This pathway may soon become more viable as key patents expire. The patent on semaglutide, the active ingredient in Novo Nordisk’s Wegovy, is due to expire in several countries in 2026. Once this occurs, manufacturers in India, Canada, China, Brazil, Turkey, and other jurisdictions will be able to develop and sell more affordable versions.
The WHO also underscored three persistent barriers that must be addressed to achieve global access:
- Limited production capacity, availability, and affordability.
- Health system readiness to prescribe and monitor the medicines.
- Universal access to healthcare services.
Dr Tedros stressed the organisation’s “greatest concern is equitable access”.
Calls for national action on prevention and supportive environments
While pharmacotherapy can assist individuals living with obesity, the WHO stated that countries must continue to prioritise prevention and create healthier environments. This includes promoting physical activity, improving food systems, and ensuring that population-level interventions accompany advances in medical treatment.
How GLP-1 obesity medicines work
GLP-1 medicines work by mimicking a natural hormone that slows digestion, suppresses appetite, and increases feelings of fullness. This results in people eating less and typically losing weight within a few weeks of starting treatment.
In the United Kingdom, GLP-1 medicines are prescription-only and can only be supplied following clinical assessment by a healthcare professional. Some formulations are available through the NHS, although many are obtained privately. A black market for these medicines exists, and the WHO and UK regulators warn that people should avoid unregulated sources such as beauty salons or social media sellers.
Research suggests that people often regain much of the weight within a year after stopping GLP-1 therapy, as physiological hunger cues return. This further reinforces the need for comprehensive, long-term behavioural support.
Global obesity burden and associated risks
Obesity affects people in every country and was associated with 3.7 million deaths worldwide in 2024, according to the WHO. Being overweight or living with obesity increases the risk of numerous serious health conditions, including type 2 diabetes, cardiovascular disease, stroke, and several cancers. The WHO’s statement highlights the immense public health implications if access to effective interventions continues to lag far behind global need.
Expert commentary
The WHO statement was authored by senior clinicians Francesca Celletti, Luz De Regil, and Jeremy Farrar, the organisation’s Assistant Director for Health Promotion and Disease Prevention and Control. Dr Farrar formerly served as WHO Chief Scientist and Director of the Wellcome Trust in London.
Katherine Jenner, Executive Director of the United Kingdom’s Obesity Health Alliance, emphasised that medicines are only part of the solution. She stated: “Weight loss drugs have an important role to play, but they are not a silver bullet. In the United Kingdom right now, access is still limited, supply is fragile, and NHS use is tightly targeted. These powerful medicines can help individuals with chronic obesity, but they are not suitable for everyone and must be accompanied by comprehensive support to be used safely and effectively. Evidence shows that most people regain weight once they stop taking these drugs, and we cannot medicate two-thirds of the population indefinitely.”
CCH insight:
The limited supply of GLP-1 medicines globally is of course frustrating, but until new drugs come to market, and just liraglutide, semaglutide and tirzepatide available, this is likely to continue. All three of these drugs are polypeptides, delivered via injection ‘pens’ and must be refrigerated, so they are expensive and complicated to produce. However, new GLP-1 medications are in development which should improve access and reduce costs, such as orforglipron – a small molecule which is easier to produce and can be taken orally in pill form.
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