Research shows that by 2022, there will be an estimated 828 million people aged 18 and over with type 1 and type 2 diabetes worldwide. Of the 445 million adults aged 30 and over, 59% are untreated.

The World Health Organization (WHO) previously estimated that about 422 million people have diabetes, a chronic metabolic disease involving high blood sugar levels that can damage the heart, blood vessels, nerves and other organs if left untreated.

Research shows that diabetes rates have doubled worldwide since 1990, from around 7% to 14%, mostly in low- and middle-income countries. But despite more cases, treatment rates in those countries have barely increased, while some higher-income countries have improved, leading to a widening treatment gap.

In some parts of sub-Saharan Africa, for example, only 5-10% of people with diabetes are estimated to be treated because treating diabetes with insulin or medication can be costly, said Jean Claude Mbanya, a professor at the University of Yaounde I in Cameroon. “A large number of people are at risk of serious health complications,” he said.

The study, conducted by the NCD Risk Factor Collaboration and WHO, is the first worldwide analysis to include rates and treatment estimates for all countries based on more than 1,000 studies involving more than 140 million people, the authors said.