More people with type 1 diabetes are living longer, but there are still global inequalities

An analysis of data from more than 200 countries and regions, published in The BMJ, found that the number of people aged 65 and over with type 1 diabetes increased from 1.3 million in 1990 to 3.7 million in 2019, while the death rate fell by 25%, from 4.7 per 100,000 population in 1990 to 3.5 in 2019.

Overall, the results show that more people with type 1 diabetes are living longer. However, death rates have fallen 13 times faster in high-income countries than in low- and middle-income countries, suggesting that there are significant global inequalities in diabetes care.

Type 1 diabetes has traditionally been thought of as a disease that can seriously shorten life expectancy, but recent studies report a growing number of older people with type 1 diabetes, likely due to improved treatments and care.

However, accurate data on the burden of type 1 diabetes are still lacking in most countries and regions of the world.

To address this issue, researchers in China used data from the Global Burden of Disease and Risk Factors 2019 study to estimate prevalence (the number of people with the condition), mortality, and disability-adjusted life-years (DALYs) lost - a combined measure of the quantity and quality of life - due to type 1 diabetes in people aged 65 and older in 204 countries and regions from 1990 to 2019.

The data were analysed at the global, regional and national levels by age, sex and the sociodemographic index (SDI) - a measure of social and economic development.

The team found that globally, the age-standardized prevalence of type 1 diabetes among older people increased by 28%, from 400 per 100,000 population in 1990 to 514 in 2019, while mortality decreased by 25%, from 4.74 per 100,000 population in 1990 to 3.54 in 2019.

Age-standardised DALYs due to type 1 diabetes also declined over the same period, but to a lesser extent, by 8.9%, from 113 per 100,000 population in 1990 to 103 in 2019.

Globally, the prevalence of type 1 diabetes has increased at least threefold in every age group from 65 to 94 years, particularly among men, while mortality rates have fallen in all age groups, particularly among women and those under 79 years. The largest reduction in DALYs has also been seen among those under 79 years.

However, mortality rates fell 13 times faster in countries with a high sociodemographic development index compared to countries with a low or medium sociodemographic development index (-2.17% per year versus -0.16% per year).

Although the highest prevalence of type 1 diabetes remained in high-income North America, Australia and Western Europe, the highest DALYs were found in southern Sub-Saharan Africa (178 per 100 000 population), Oceania (178) and the Caribbean islands (177).

High fasting plasma glucose (higher blood sugar levels after a period of fasting) was the main risk factor for DALYs among older people with type 1 diabetes over the 30-year study period, suggesting that active blood glucose control remains a challenge for these patients.

The researchers acknowledge that their estimates relied heavily on modelling, and that variations in health systems and reporting methods across countries and regions, particularly in low- and middle-income countries and conflict-affected areas, may have affected the accuracy of their results.

However, for older people with type 1 diabetes and their families worldwide, the reduction in deaths and DALYs associated with the disease is encouraging.

Further high-quality research in the real world is needed to validate the findings of this study. The researchers write: "Our study also advocates urgent attention to strategies to address the challenges of an ageing population and older people with type 1 diabetes, rational distribution of healthcare, and provision of targeted recommendations."