A report from global experts has claimed that there is a risk with too many individuals being diagnosed as obese, according to their body mass index (BMI), when “a more accurate” and “nuanced” definition is needed to help identify people who need to manage their weight to stay healthy. Published in The Lancet Diabetes & Endocrinology journal, the report is supported by over 50 global medical experts.
The report says that doctors need to consider the overall health of patients with excess fat, rather than simply measuring body mass index. Those with chronic illnesses caused by their weight should be diagnosed with ‘clinical obesity’, however those with no health problems should be diagnosed with ‘pre-clinical obesity’.
“Obesity is a spectrum. Some have it and manage to live a normal life, function normally. Others can’t walk well or breathe well, or are wheelchair bound with significant health issues,” says Professor Francesco Rubino, from King’s College London, who chaired the group.
Subsequently, the report calls for a “reframing” of obesity to better distinguish between patients with a disease and those who remain healthy, but are at risk of disease in the future.
Over a billion people are estimated to be living with obesity worldwide, with most countries defining obesity as having a BMI over 30. As a result, prescription weight-loss drugs are in high demand, but are often restricted to the patients in the over 30 BMI category.
In many parts of the UK, the NHS also requires people to have a weight-related health condition to access these drugs. But BMI cannot determine a patient’s overall health, the report says, as it fails to distinguish between muscle and body fat or account for the more dangerous fat around the waist and organs.
The experts argue for a new model that looks at signs of obesity affecting organs in the body, such as heart disease, breathlessness, type 2 diabetes or joint pain and their damaging impact on daily life.
Waist-height ratios or direct fat measurement, along with a detailed medical history, can give a much clearer picture than BMI, the report says.
Those with ‘pre-clinical obesity’, instead of drugs and surgery, should be offered weight-loss advice, counselling and monitoring to reduce the chances of health problems developing. In some cases, treatment may also be necessary.
Children’s obesity expert Prof Louise Baur, from the University of Sydney, who contributed to the report, said the new approach would allow adults and children with obesity “to receive more appropriate care”, while reducing the numbers being over-diagnosed and given unnecessary treatment.
The Royal College of Physicians said the report was a strong starting point “for treating obesity with the same medical rigour and compassion as other chronic illnesses”.
Distinguishing between pre-clinical and clinical obesity would be “a vital step forward” and “highlighted the need to identify and intervene early” while providing the right care to patients whose health was already severely affected, the college said.
But there are concerns that strain on health budgets could mean less money for those in the ‘pre-obese’ category. Prof Sir Jim Mann, co-director of the Edgar Diabetes and Obesity Research Centre, in Otago, New Zealand, said the emphasis was likely to be “on the needs of those who are defined as clinically obese” and the limited funding was “very likely” to be directed towards them.