China has the highest number of diabetics in the world with an estimated 92.4 million sufferers, 61 percent of whom have yet to be diagnosed, experts warned on Sunday.

People who go without being properly diagnosed are more likely to have blood glucose that is poorly controlled, which leaves them open to the risk of developing complications that affect their eyesight and kidneys, having a stroke or a limb amputated, experts said.

"A combination of poor public awareness and limited access to early detection services are largely responsible for the low diagnostic rate on the mainland," Ji Linong, head of the Chinese Diabetes Society (CDS), said on Sunday at an event marking World Diabetes Day, which annually falls on Nov 14.

"The government should spend more on services to intervene and prevent diabetes," he said, recommending a universal screening program for high-risk groups.

Those aged over 40, overweight or living in well-off urban areas are at a higher risk of developing diabetes, medical studies have shown. Overweight children are also susceptible to developing the disorder.

"Early diagnosis and treatment would help provide effective medical intervention, which lowers the costs incurred," Ji said.

According to the latest study jointly conducted by the CDS and the International Diabetes Federation (IDF), 13 percent of the total medical expenditure in China, around $25 billion, is related to diabetes.

People with diabetes in China require three to four times more inpatient care, as well as outpatient and emergency room visits, than their healthy counterparts of the same age and sex, the study found.

Without intervention, "the cost of treating diabetes will rise rapidly in the next 10 to 20 years, as patients who have gone undiagnosed develop serious complications whose treatment will definitely cost more," Ji said.

In emerging countries like China and India, phenomenal changes like rapid economic growth, new trends such as mass urbanization, different diets and increasingly sedentary lifestyles have all greatly increased the risk of developing diabetes.

Worldwide, diabetes currently affects more than 300 million people and is expected to cost the global economy at least $376 billion in 2010, or 11.6 percent of the total world expenditure on healthcare, IDF statistics show.

"It has become a leading threat to global health and development," IDF President Jean Claude Mbanya warned on Sunday.

Without intervention, by 2030 there will be 500 million people throughout the world with diabetes at a projected cost of more than $490 billion for the global economy, he estimated.

"Policymakers need to integrate plans for diabetes prevention into national health systems and countries have to find ways to develop economically in a way that is not harmful to public health," Mbanya said.