IDF Atlas: 1 in 10 Adults Worldwide Now Has Diabetes

One in 10 adults worldwide currently has diabetes, accounting for an estimated global health expenditure of $966 billion in US dollars in 2021, according to the new International Diabetes Federation (IDF) Diabetes Atlas.

The IDF Atlas, 10th edition, was published online December 6, 2021.

Highlights from it were presented during two sessions at the IDF Virtual Congress 2021, covering global diabetes incidence and prevalence, mortality, and costs, as well as new sections in this edition devoted to adult-onset type 1 diabetes, childhood-onset type 2 diabetes, and the interactions between diabetes and COVID-19.

More detailed data from some of the Atlas chapters were also published December 6 in separate papers in the IDF journal Diabetes Research and Clinical Practice, with more publications planned.

Information for the Atlas comes from peer-reviewed literature, unpublished reports, and national registries. This latest edition includes 219 data sources from 144 countries, with figures for other countries extrapolated.

Atlas co-chair Dianna Magliano, PhD, reviewed some of the highlights. Half of those currently with diabetes, or about 240 million adults, are undiagnosed, and another 319 million have impaired fasting glucose. Over three quarters of all adults with diabetes now live in low- and middle-income countries. And about 6.7 million deaths in 2021 can be attributed to diabetes.

The Atlas also predicts increases in these numbers over the coming decades if current trends continue.

"Our data and projections tell a sobering story. Diabetes prevalence is expected to increase globally. The number of adults with diabetes will rise from 537 million in 2021 to 786 million...by the year 2045, an increase of 46%. Rises are expected in every region of the world, with the largest increases expected to occur in the regions of Africa, the Middle East, and Southeast Asia," said Magliano, head of diabetes and population health at the Baker Heart and Diabetes Institute, Melbourne, Australia.

Since 2019, when the last Atlas was published, the 2021 numbers represent increases of 73.6 million more adults with diabetes including 7.8 million more undiagnosed, 2.5 million more deaths attributed to diabetes, and an additional global expenditure of $206 billion.

Increases have also occurred in the number of people with prediabetes, children with type 1 diabetes, and pregnancies affected by diabetes, Magliano reported.

"There is a strong need for effective intervention strategies and policies to stall the increase in the number of people developing diabetes across the world," she added.

Projected Rise in Expenditures for Diabetes Will Be "Unsustainable"

The current $966 billion global health expenditure due to diabetes represents a 316% increase from the $232 billion reported in 2006, according to William H. Herman, MD, professor of internal medicine and epidemiology at the University of Michigan, Ann Arbor.

By region, 43% of current diabetes-related global expenditures are in North America, 25% in the Western Pacific, and 20% in Europe, while 12% are from the regions of South and Central America, North Africa, Africa, and Southeast Asia combined, Herman said.

The direct costs of diabetes are projected to grow to $1054 billion in 2045, an increase of just 9% over 25 years. The reason for the far lower increase going forward compared to the tripling in the 15 years prior is due to the anticipated diabetes rise in regions of the world where per-person spending on diabetes is low, a situation Herman called "unsustainable."

"The keys to controlling the global costs of diabetes care are diabetes prevention and providing effective care to the largest number of people at the lowest possible cost," he said.

Diabetes-Related Mortality: Some Shifts Since 2019

One third of the current 6.7 million diabetes-related deaths in 2021 were in people younger than 60 years, said Elbert S. Huang, MD, professor of medicine and public health sciences at the University of Chicago, Illinois.

Overall, diabetes accounted for 11.8% of total global deaths in people younger than 60 years, but that varied widely, from 24.5% in the Middle East/North Africa to just 6.9% in Southeast Asia.

The regions with the highest number of diabetes-related deaths in people younger than 60 years in 2021 were the Western Pacific and the Middle East/North Africa, a major change from just 2 years ago, when Southeast Asia and Africa saw the greatest numbers of diabetes-related deaths in working-age adults.

"These findings mirror recent reports on inadequate uptake of diabetes prevention programs as well as stagnant quality of care trends for the past decade and reemphasize the need to address noncommunicable diseases across the globe," Huang said.

Diabetes and COVID-19: Other Factors Partly Explain the Increased Risk

Gillian Booth, MD, summarized the current literature on COVID-19 and diabetes including a meta-analysis her group conducted of 300 studies from around the world, with 58% from high-income countries.

The risk for increased COVID-19 severity in people with diabetes could be at least partly explained by factors such as age, sex, and comorbidities, said Booth, professor in the department of medicine and the Institute of Health Policy, Management, and Evaluation at the University of Toronto, Ontario, Canada.

For example, the unadjusted pooled odds of hospitalization with COVID-19 in patients with diabetes compared to those without diabetes was 3.69, but dropped to 1.73 after adjustment for age, sex, and having one or more comorbidities. For COVID-19-related death, those odds ratios were 2.32 unadjusted versus 1.59 adjusted. In both cases, the values were still significant after adjustment, she emphasized.

Overall, hyperglycemia and A1c at admission emerged as significant independent predictors of severe outcomes.

"Further research is needed to understand the interplay between COVID-19 and diabetes and how best to address the disproportionate burden of COVID-19 among people living with diabetes," she stressed.

Adult-Onset Type 1 Diabetes: Growing Recognition of the Burden

Ascertainment of data for both adult-onset type 1 and type 2 diabetes in youth was subject to significant limitations.

For adult-onset type 1 diabetes, Jessica Harding, PhD, pointed to the fact that the epidemiology of adult-onset type 1 diabetes hasn't been well characterized due to the historical focus on children, the difficulty of distinguishing it from type 2 diabetes in adults, and that many registries simply don't include incident data across the lifespan for type 1 diabetes.

Nonetheless, she said, "There is growing recognition of the burden of adult-onset type 1," noting that the American Diabetes Association and European Association for the Study of Diabetes just published a consensus statement addressing the topic.

A systematic review of 46 studies representing 32 countries or regions revealed that countries with the highest incidence of type 1 diabetes onset per population of 100,000 ages 20 or above were Eritrea, at 46.2, followed by Sweden and Ireland, both at 30.6, and Finland, at 0. The lowest rates were in Asian countries.

While the Nordic countries (Finland, Sweden, and Norway) are among the top for incidence of both childhood-onset (0-14 years) and adult-onset type 1 diabetes, Eritrea isn't even among the top 10 for childhood-onset.

The unusual situation in Eritrea is the subject of current study but the reasons aren't yet clear, noted Magliano, of the Emory University School of Medicine, Atlanta, Georgia, during the question-and-answer period.

And only seven studies, 15%, used biomarkers to determine type 1 diabetes status, suggesting "there is a pressing need to improve the quality and quantity of information on adult-onset type 1 diabetes, particularly in those low and middle-income countries," Harding said.

Type 2 Diabetes in Youth: A Call for Better Data

When presenting the data for childhood-onset type 2 diabetes, Andrea Luk, MD, noted: "The onset of advanced complications during the most productive time of life has significant impact on individuals, communities, and health economies."

In 19 studies, the highest reported prevalence of type 2 diabetes in youth was in Brazil, Mexico, indigenous populations of the United States and Canada, and the Black population in the United States, with rates ranging from 160 per 100,000 to 3300 per 100,000. The lowest prevalence rates of 0.6 per 100,000 to 2.7 per 100,000 were reported in Europe. Incidence data were similar, with the highest rates from 31 per 100,000 to 94 per 100,000 and the lowest 0.1 per 100,000 to 0.8 per 100,000 per year.

Of note, Luk pointed out that childhood obesity is an important factor but not the only one.

"Some populations that have a low prevalence of obesity, such as East Asians, reported higher incidence rates of youth-onset type 2 diabetes than populations with a greater burden of childhood obesity."

There was variability in incidence rates for youth of similar ethnic background but from different countries. "Apart from genetic predisposition and background obesogenic environment, disparity in socioeconomic status, access to health care, and cultural practices are other contributors to differences in risk of type 2 diabetes in youth," note Luk, associate professor in the division of endocrinology, Department of Medicine and Therapeutics, Chinese University of Hong Kong.

She also noted that the incidence of type 2 diabetes was extremely low in pre-pubertal children and rises gradually during puberty, and that the incidence is higher in girls than boys but that reverses in adulthood.

Compared to adults with type 2 diabetes, youth with type 2 diabetes had a more adverse glycemic trajectory and higher rates of metformin failure.

And compared to youth with type 1 diabetes, those with type 2 diabetes had more adverse metabolic profiles and higher rates of vascular complications.

"A strong call must be made for the collection of trend data to assess global burden of type 2 diabetes in youth," she concluded.

Luk has reported serving as an advisory panel member for and/or receiving research support from Amgen, AstraZeneca, Boehringer Ingelheim, Sanofi, the Asia Diabetes Foundation, Bayer, Lee's Pharmaceutical, MSD, Novo Nordisk, Roche, Sugardown, and Takeda. The other authors have reported no relevant financial relationships.

IDF Diabetes Atlas 2021. Available here.

IDF Virtual Congress 2021. Presented December 6, 2021.

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape, with other work appearing in The Washington Post, NPR's Shots blog, and Diabetes Forecast magazine. She is on Twitter: @MiriamETucker.

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