'Move Beyond BMI,' New European Obesity Framework Advises

A new European framework statement calls for consideration of metrics beyond body mass index (BMI) when diagnosing and classifying obesity.

The consensus-based statement, from the European Association for the Study of Obesity (EASO), provides an algorithm for diagnosing and staging obesity based on BMI, fat accumulation, and a clinical component including medical, functional, and mental domains. Also included is a set of 28 consensus statements covering clinical staging and diagnosis, "pillars of treatment," therapeutic targets, and initial level of intervention.

"The incidence and prevalence of obesity remains on the rise globally. Despite the wide recognition of obesity as a multifactorial, complex, chronic disease, clinical recommendations that guide the diagnosis and management of obesity are not aligned with clinical processes normally adopted for other chronic diseases. Moreover, effective new management modalities are emerging," the authors said in a joint statement provided to Medscape Medical News.

Thus, they say, "there is an urgent need to adapt the framework currently used in obesity management. A framework that better aligns with the concept of obesity as an adiposity-based chronic disease is needed. Crucially, we need to move beyond BMI, taking into account abdominal fat accumulation, along with medical, functional and psychological impairments."

The statement was published on July 5, 2024, in Nature Medicine. The first author is Luca Busetto, MD, associate professor of medicine at the University of Padova, Padua, Italy. It is not a guideline but rather a "framework on which guidelines can be built," Busetto said.

New Paradigms: Lower BMI Cutoff Plus High Waist-Height Ratio, Cancer Assessment

Asked to comment, W. Timothy Garvey, MD, professor and director of the University of Alabama Diabetes Research Center, Birmingham, Alabama, told Medscape Medical News, "I think it's a very concise, straightforward document. You stage the disease and treat according to how sick the patient is, which means the severity of their complications. This is consistent with a lot of other guidelines, beginning with those of the American Association of Clinical Endocrinology [AACE] in 2016."

However, there are several new and noteworthy elements in this framework, noted Garvey, who was lead author of the 2016 AACE guidelines. One is a call for measuring waist to height ratio rather than just waist circumference. Another is the lowering of the BMI cutoff to ≥ 25 kg/m2 plus a waist-to-height ratio > 0.5 as "conferring an increased risk for progressing to medical, functional, or psychological impairments or complications in adults of European descent." This tenet, with a 65% consensus, was based on the recognition of excessive fat accumulation even with lower BMI, according to the document.

Also new are recommendations for assessing sarcopenic obesity in those who may be at risk and for ensuring that people with obesity have regular screening for obesity-related cancers. The latter, Garvey said, "isn't across the board in all guidelines, but it makes sense from what we know."

According to the authors, "The refinement of obesity diagnosis is under construction. We anticipate that, in conjunction with other ongoing initiatives, this new framework will contribute to improving obesity management for adults with obesity. We are sure that more detailed diagnostic parameters and possibly therapeutic algorithms will be developed in the future."

Treatment 'Pillars' Await More Data to Enable Personalized Guidelines

Seven of the 28 statements address "pillars of treatment," focusing on long-term, multidisciplinary management including behavioral modification for all with obesity, and consideration of psychological therapy, obesity medications, and bariatric surgery for some.

The statement advises prescribing medications as adjunct to behavioral modification confirming to the approved labeling — ie, BMI ≥ 30 kg/m2 or ≥ 27 kg/m2 with an obesity-related disease or complication. However, they also suggest considering the use of obesity medications in adults of European descent with BMI ≥ 25 kg/m2 and a waist-to-height ratio > 0.5 and the presence of medical, functional, or psychological impairments or complications.

"Taking medicines into the 25 [BMI] range is new…It recognizes that what's important is not just fat mass, it's fat distribution and function. Again, that's consistent with adiposity-based chronic disease," Garvey commented.

Missing from the document, Garvey pointed out, are detailed treatment guidelines and detailed descriptions of how to evaluate patients. There is also no discussion of social determinants of health or internalized weight bias and stigma, the subject of a recent AACE consensus statement. "Stigmatization is something that can impair quality of life and even impair the patient's adherence to therapy," he noted.

Updated treatment guidelines are likely to ensue from the ongoing emergence of data for the newer obesity medications, Garvey said.

"We haven't been able to provide hierarchies of preferred medicines like we do in diabetes, because the data just wasn't there. But now with second generation obesity medicines, the drug companies are conducting clinical trials with complications as the primary outcome," he said, citing the examples of SELECT, STEP-HFpEF, FLOW, and SURMOUNT-OSA.

"They're showing that these medicines and the associated weight loss helped patients where it counts, and that these complications…And as the data accumulates, we'll be able to recommend certain medicines for patients who have certain complications."

Garvey also said he hoped this document would help diminish the practice of online mail-order pharmacy prescribing the newer obesity medications by physicians who are licensed in the patient's state but who don't examine them. "This is completely contrary to obesity care as outlined within the EASO framework/algorithm. There is no exam, no clinical component to the diagnosis, no assessment of obesity complications and related diseases, and no possibility of complications-centric care. Our patients deserve better."

The authors told Medscape Medical News, "Access to effective evidence-based management for obesity remains elusive. However, obesity is a chronic relapsing disease which requires both an understanding of its multifactoral causes and accurate diagnosis…Adoption of the Framework can facilitate better access to appropriate obesity management."

Busetto received personal funding from Novo Nordisk, Boehringer Ingelheim, Eli Lilly, Pfizer, Bruno Farmaceutici as a member of advisory boards, and from Rythms Pharmaceuticals and Pronokal as a speaker. Other authors also have industry disclosures. Garvey provided expertise in the early stages of the statement's development but had no role in its writing. He consults on advisory boards for Boehringer Ingelheim, Eli Lilly, Novo Nordisk, Pfizer, Fractyl Health, Alnylam Pharmaceuticals, Inogen, Zealand, Allurion, Carmot/Roche, and Merck, and conducts clinical trials sponsored by his university and funded by Novo Nordisk, Eli Lilly, Epitomee, Neurovalens, and Pfizer. He also consults for the nonprofit Milken Foundation.

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape Medical News, with other work appearing in the Washington Post, NPR's Shots blog, and Diatribe. She is on X @MiriamETucker.