LONDON, Jan 14 (Reuters) - Doctors worldwide should

diagnose obesity differently, relying on broader criteria and

taking into account when the condition causes ill-health,

according to a new framework drawn up by experts and endorsed by

76 medical organizations internationally.

At the moment, clinicians use BMI or body mass index to

diagnose obesity, a calculation based on a person's weight and

height. But this tool is not precise enough and they should also

take other measurements, such as waist circumference, to avoid

misdiagnosis, the 56 experts who took part in the global

commission said.

Obesity should also be split into two categories, 'clinical

obesity' and 'pre-clinical obesity', the commission said, in a

paper published on Tuesday in The Lancet Diabetes and

Endocrinology journal.

Clinical obesity involves excess body fat plus symptoms of

reduced organ function - like breathlessness or heart failure -

or problems going about daily life. It should be considered as a

chronic disease and treated accordingly, the experts propose.

Pre-clinical obesity is obesity or excess body fat without

any signs of ongoing illness, and normal organ function. It

should be considered a risk factor both for clinical obesity and

other illnesses like diabetes, the commission said, and patients

should be supported to reduce that risk, either through

monitoring or active treatment.

"Obesity is a spectrum," said commission chair, Francesco

Rubino, a professor at King's College London, at a press

conference earlier this week.

More than one billion people are currently estimated to have

obesity globally.

The experts said they aimed to make diagnosis more precise,

which could help better use healthcare resources. They said it

was not yet clear if it would lead to more or fewer people being

diagnosed, but they hoped it would settle the polarising debate

within the medical establishment over whether obesity is a

disease.

"We cannot afford to have a blurry picture of obesity," said

Rubino.

The guidelines were backed by organisations including the

American Heart Association and the Chinese Diabetes Society, as

well as the World Obesity Federation.

World Health Organization experts served on the commission,

which began work in 2019.

The advent of the GLP-1 class of drugs to treat obesity,

first developed by Eli Lilly ( LLY ) and Novo Nordisk, had changed the

landscape since then, Rubino said, but the use of the drugs was

not the commission's focus. However, he said clearer diagnosis,

if adopted by healthcare systems worldwide, could help doctors

decide when best to prescribe them based on individual risk.

The commission also said it could mean health insurers may

consider covering the drugs for clinical obesity as a standalone

illness. Many currently require another related condition to be

present, like diabetes.

"We hope this leads to a change in practice, and maybe even

before that, a change in mindset," said Rubino.