Newly diagnosed cases of diabetes have slowed globally, according to multinational registry data.
According to Dianna Magliano, PhD from the Baker Heart and Diabetes Institute in Melbourne, Australia and colleagues, almost all of 19 high-income and two middle-income countries saw new diabetes cases decline or stabilize from around 2010 onwards.
Of all the sites included, Lithuania, Singapore, Israel and the Northwest US were the only areas where there were increases in new diabetes cases, the group wrote in Lancet Diabetes & Endocrinology.
In these areas, the estimated annual increase in new diabetes cases since 2010 has been between 0.9% and 5.6%.
Looking only at the US, which had three sources of data, new diabetes cases among Medicare beneficiaries and respondents to the National Health Interview Survey declined overall. The increase in cases was only seen in the patients in the Kaiser Permanente Northwest insurance record.
All other countries and jurisdictions included in the analysis have seen a decrease in the number of new diabetes cases since 2010, falling from 1.1% to 10.8%: Australia, Canada, Denmark, France, Hong Kong, Italy in Lombardy, Latvia, Netherlands, Norway, Russia, Scotland, South Korea, Spain, Taiwan, Great Britain and Ukraine.
Virtually all of these countries and jurisdictions specifically addressed type 2 diabetes cases, although some areas included the incidence of type 1 and type 2 diabetes cases.
The registration dates for the analysis were extended to 2015 or 2016 for most of the countries examined.
Magliano’s group pointed out that while the causes of the huge decline in diabetes cases around the world are “uncertain”, they are likely due to increased prevention efforts.
Another factor likely to affect the incidence of diagnosed cases of diabetes was the formal introduction of HbA1c to diagnose diabetes – the earliest of which occurred in the US in 2010.
“There is evidence that HbA1c detects fewer people with diabetes than the oral glucose tolerance test (OGTT),” the researchers wrote. “However, OGTT is rarely used in clinical practice and fasting glucose, the most widely used test to diagnose diabetes, results in a prevalence of diabetes similar to that of HbA1c.”
Magliano and co-authors found that two countries that have never officially introduced screening with HbA1c – France and Latvia – also saw decreases in new cases.
Another possible explanation for these decreasing or stabilizing cases of diabetes could be traced back to the fact that the diagnostic threshold for fasting plasma glucose in 1997 went from 7.8 mmol / L (140 mg / dL) to 7.0 mmol / L (126 mg / dL) was lowered. This diagnostic change would have resulted in a number of new cases diagnosed in the years that followed, which would have resulted in a possible decline or stabilization by 2010.
For the analysis, the researchers relied on data from 22 million new diabetes diagnoses, spanning 5 billion person-years of follow-up. All included countries and jurisdictions were rated as “high income” while only two were rated as “high income” (Russia and Ukraine).
This was highlighted in an accompanying comment by Mohammed K. Ali, MBChB, MSc, MBA at Emory University in Atlanta and colleagues who said the absolute rate of global diabetes cases continues to rise slowly.
“Importantly, the results are limited to high-income populations and cannot speak to diabetes incidence patterns in low- and middle-income countries, where 79% of people with diabetes worldwide live,” wrote Ali’s group.
Commentators also noted that the analysis only indicated that newly diagnosed cases of diabetes rejuvenate in those with access to health care or those with administrative records to their health and, therefore, are unlikely to include many socio-economically weaker or uninsured people.
The study was funded by the CDC, Diabetes Australia Research Program, and the Victoria State Government’s Operational Infrastructure Support Program.
Magliano and co-authors reported no information.
Ali and co-authors reported relationships with Merck and the Georgia Center for Diabetes Translation.