Global commission proposes comprehensive framework for obesity diagnosis and treatment
A newly published report by a global Commission, featured in The Lancet Diabetes & Endocrinology and endorsed by 75 medical organisations worldwide, calls for a transformative approach to diagnosing and managing obesity. The report challenges the long-standing reliance on body mass index (BMI) as a sole diagnostic tool, deeming it insufficient on its own.
The Commission comprised 56 leading experts, including Professor Louise Baur, a Professor of Child and Adolescent Health at the University of Sydney and former President of the World Obesity Federation. The multidisciplinary team also featured medical specialists from the United States, United Kingdom, India, and Brazil, as well as individuals living with obesity. Together, they have developed a framework to improve care by addressing the complexity of obesity as a chronic condition.
Rethinking Obesity Diagnosis
The report advocates for a shift in diagnostic criteria, urging healthcare professionals to measure excess body fat alongside BMI and evaluate clinical signs and symptoms of ill health, such as breathlessness or joint stiffness. This broader perspective aims to provide tailored, evidence-based care for each individual.
Two new diagnostic categories have been introduced:
- Clinical Obesity: A chronic disease characterised by organ dysfunction due to excess body fat.
- Pre-clinical Obesity: A condition where individuals have high levels of body fat without current illness but are at elevated risk of future health complications.
Professor Baur emphasised the need for this shift, stating, “Over a billion people across the world live with obesity, which increases the risk of developing serious conditions such as type 2 diabetes and certain types of cancers. But despite this, people are often diagnosed as having obesity using a single, catch-all measure that is not tailored to the individual. Taking a more nuanced approach will allow people to receive care that is proportionate to their needs.”
Limitations of BMI as a Standalone Measure
BMI has been a standard tool for assessing obesity by calculating weight relative to height. However, the Commission highlights its significant limitations. BMI does not directly measure body fat or account for its distribution, which is critical in assessing health risks. For instance:
- Some individuals with lower BMI may store dangerous levels of fat around vital organs like the liver or heart, increasing their risk of cardiovascular disease.
- BMI was initially designed for populations of European descent and does not adequately account for the diverse risk factors across different ethnic groups.
These shortcomings underline the need for more precise and inclusive diagnostic methods.
Proposed Diagnostic Alternatives
The Commission recommends replacing BMI as a standalone measure with more comprehensive assessments, including:
- Combination of Metrics: BMI supplemented by measurements like waist circumference, waist-to-hip ratio, or waist-to-height ratio.
- Direct Measurement of Body Fat: Techniques such as bone densitometry scans (DEXA) to provide more accurate data.
- Pragmatic Assumptions: In individuals with very high BMI, excess fat may be assumed without further measurements.
Defining Clinical and Pre-clinical Obesity
To enhance the precision of obesity diagnosis, the Commission outlines distinct definitions for two new categories:
Clinical Obesity
This is a chronic disease where excess fat impairs organ function or limits daily activities, such as bathing or dressing. The report identifies 18 diagnostic criteria for adults and 13 for children and adolescents, including:
- Breathlessness caused by lung dysfunction.
- Heart failure due to obesity.
- Joint pain and stiffness, particularly in the knees or hips, caused by excess body weight.
- Altered bone and joint structures in children, restricting movement.
- Signs of dysfunction in various organs, such as the kidneys, lymph system, and metabolic organs.
Pre-clinical Obesity
This category includes individuals with high body fat levels but no current signs of illness. While their organ function remains normal, they are at increased risk of developing chronic conditions, such as cardiovascular disease. Early intervention for this group focuses on risk reduction to prevent the progression to clinical obesity.
Professor Baur hopes these definitions will improve communication between healthcare professionals and patients, “We hope that these new definitions will make it easier for clinicians and patients alike to have discussions about their health, and to get the care that they need without stigma or judgement.”
Personalised Care and Resource Allocation
Commission Chair Professor Francesco Rubino, from King’s College London, explained the significance of the new framework, “Our reframing acknowledges the nuanced reality of obesity and allows for personalised care. This includes timely access to evidence-based treatments for individuals with clinical obesity, as appropriate for people suffering from a chronic disease, as well as risk-reduction management strategies for those with pre-clinical obesity, who have an increased health risk, but no ongoing illness. This will facilitate a rational allocation of healthcare resources and a fair and medically meaningful prioritisation of available treatment options.”
Conclusion
By recognising the limitations of BMI and adopting a more comprehensive diagnostic framework, the Commission aims to provide more equitable, evidence-based care for individuals living with or at risk of obesity. This nuanced approach ensures that treatments and interventions are better aligned with each person’s unique health profile, paving the way for improved outcomes and reduced stigma in obesity care.
