Type 1 Diabetes Cases Poised to Double Worldwide by 2040
STOCKHOLM, Sweden — The number of people living with type 1 diabetes worldwide is expected to double by 2040, with most new cases among adults living in low- and middle-income countries, new modeling data suggest.
The forecast, developed from available data collected in the newly established open-source Type 1 Diabetes Index,
provides estimates for type 1 diabetes prevalence, incidence, associated mortality, and life expectancy for 201 countries for 2021.
The model also projects estimates for prevalent cases in 2040. It is the first type 1 diabetes dataset to account for the lack of prevalence due to premature mortality, particularly in low- and middle-income countries.
The worldwide prevalence of type 1 diabetes is substantial and growing.
Improved surveillance — particularly in adults who make up most of the population living with type 1 diabetes — is essential to enable improvements to care and outcomes.
There is an opportunity to save millions of lives in the coming decades by raising the standard of care (including ensuring universal access to insulin and other essential supplies) and increasing awareness of the signs and symptoms of type 1 diabetes to enable a 100% rate of diagnosis in all countries," the authors write.
"This work spells out the need for early diagnosis of type 1 diabetes and timely access to quality care," said Chantal Mathieu, MD, here at the European Association for the Study of Diabetes (EASD) 2022 Annual Meeting.
One in Five Deaths From Type 1 Diabetes in Under 25s
The new findings were published in Lancet Diabetes & Endocrinology by Gabriel A. Gregory, MD, of Life for a Child Program, New South Wales, Australia, and colleagues. The T1D Index Project database was published September 21, 2022.
According to the model, about 8.4 million people were living with type 1 diabetes in 2021, with one fifth from low- and middle-income countries. An additional 3.7 million died prematurely and would have been added to that count had they lived. One in five of all deaths caused by type 1 diabetes in 2021 is estimated to have occurred in people younger than age 25 years due to nondiagnosis.
"It is unacceptable that, in 2022, some 35,000 people worldwide are dying undiagnosed within a year of onset of symptoms.
There also continues to be a huge disparity in life expectancy for people with type 1 diabetes, hitting those in the poorest countries hardest," noted Mathieu, who is senior vice-president of EASD and an endocrinologist based at KU Leuven, Belgium.
By 2040, the model predicts that between 13.5 million and 17.4 million people will be living with the condition, with the largest relative increase from 2021 in low-income and lower-middle-income countries. The majority of incident and prevalent cases of type 1 diabetes are in adults, with an estimated 62% of 510,000 new diagnoses worldwide in 2021 occurring in people aged 20 years and older.
Type 1 Diabetes Is Not Predominantly a Disease of Childhood
Mathieu also noted that the data dispute the long-held view of type 1 diabetes as a predominantly pediatric condition. Indeed, worldwide, the median age for a person living with type 1 diabetes is 37 years.
"While type 1 diabetes is often referred to as 'child-onset' diabetes, this important study shows that only around one in five living with the condition are aged 20 years or younger, two thirds are aged 20-64 years, and a further one in five are aged 65 years or older."
"This condition does not stop at age 18 years — the children become adults, and the adults become elderly. All countries must examine and strengthen their diagnosis and care pathways for people of all ages living with type 1 diabetes," Mathieu emphasized.
And in an accompanying editorial, Serena Jingchuan Guo, MD, PhD, and Hui Shao, MD, PhD, point out that most studies that estimate diabetes burden have focused on type 2 diabetes, noting, "type 1 diabetes faces the challenges of misdiagnosis, underdiagnosis, high risk of complications, and premature mortality."
The insulin affordability issue is central, point out Guo and Shao of the Center for Drug Evaluation and Safety, Department of Pharmaceutical Evaluation and Policy, University of Florida College of Pharmacy, Gainesville.
"Countries need to strengthen the price regulation and reimbursement policy for insulin while building subsidy programs to ensure insulin access and to cope with the growing demand for insulin.
Meanwhile, optimizing the insulin supply chain between manufacturers and patients while seeking alternative treatment options (eg, biosimilar products) will also improve the current situation," they conclude.
The study was funded by JDRF, of which four co-authors are employees. The editorialists have reported no relevant financial relationships
Lancet Diabetes Endocrinol. Published online September 13, 2022.
Growing global burden of type 1 diabetes needs multitiered precision public health interventions
Diabetes is a public health crisis, and diabetes-related health and economic burdens have been rising globally over the past decades, with the growth being the most striking in low-income and middle-income countries (LMICs).
Most studies in estimating diabetes burdens have been focused on type 2 diabetes with scarce evidence on type 1 diabetes.
Type 1 diabetes faces the challenges of misdiagnosis, underdiagnosis, high risk of complications, and premature mortality.
Accurate data on type 1 diabetes prevalence, incidence, associated mortality and life expectancy are crucial to inform public health policy, but these data are scarce. We therefore developed a model based on available data to estimate these values for 201 countries for the year 2021 and estimate the projected prevalent cases in 2040.
We fitted a discrete-time illness-death model (Markov model) to data on type 1 diabetes incidence and type 1 diabetes-associated mortality to produce type 1 diabetes prevalence, incidence, associated mortality and life expectancy in all countries. Type 1 diabetes incidence and mortality data were available from 97 and 37 countries respectively. Diagnosis rates were estimated using data from an expert survey. Mortality was modelled using random-forest regression of published type 1 diabetes mortality data, and life expectancy was calculated accordingly using life tables. Estimates were validated against observed prevalence data for 15 countries. We also estimated missing prevalence (the number of additional people who would be alive with type 1 diabetes if their mortality matched general population rates).
In 2021, there were about 8·4 (95% uncertainty interval 8·1–8·8) million individuals worldwide with type 1 diabetes: of these 1·5 million (18%) were younger than 20 years, 5·4 million (64%) were aged 20–59 years, and 1·6 million (19%) were aged 60 years or older. In that year there were 0·5 million new cases diagnosed (median age of onset 39 years), about 35 000 non-diagnosed individuals died within 12 months of symptomatic onset. One fifth (1·8 million) of individuals with type 1 diabetes were in low-income and lower-middle-income countries. Remaining life expectancy of a 10-year-old diagnosed with type 1 diabetes in 2021 ranged from a mean of 13 years in low-income countries to 65 years in high-income countries. Missing prevalent cases in 2021 were estimated at 3·7 million. In 2040, we predict an increase in prevalent cases to 13·5–17·4 million (60–107% higher than in 2021) with the largest relative increase versus 2021 in low-income and lower-middle-income countries.
The burden of type 1 diabetes in 2021 is vast and is expected to increase rapidly, especially in resource-limited countries. Most incident and prevalent cases are adults.
The substantial missing prevalence highlights the premature mortality of type 1 diabetes and an opportunity to save and extend lives of people with type 1 diabetes.
Our new model, which will be made publicly available as the Type 1 Diabetes Index model, will be an important tool to support health delivery, advocacy, and funding decisions for type 1 diabetes.
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