Decrease in Diabetes All-Cause Mortality Seen in High-Income Countries

Between 1995 and 2016, all-cause mortality among individuals with diabetes decreased in high-income settings including the United States, Australia, and Canada, according to a new multicountry analysis of aggregate data published in The Lancet Diabetes & Endocrinology. Jurisdictions in east and southeast Asia reported the greatest mortality decreases.

Although previous research has indicated decreasing rates of mortality in this population within the past decade, little is known regarding trends stratified by age and sex. Different analyses can also employ different assessment methods, complicating the data yielded.

In an effort to address these knowledge gaps, researchers established a multicountry assembly of individual-level data with the aim of examining the magnitude and trends in excess all-cause mortality related to diabetes.

Data from individuals with diagnosed total (type 1 and type 2 diabetes) or type 2 diabetes (hereafter referred to as diabetes) residing in 16 different high-income countries were included in the analysis. “Death in people with diabetes was determined via linkage to national death registries or national population registers,” authors explained.

Age was defined as the midpoint of each age group (<20, 20–24, 25–29, 30–34, 35–39, 40–44, 45–49, 50–54, 55–59, 60–64, 65–69, 70–74, 79–80, 80–84, and ≥85 years). To conduct the analysis, researchers used 6 data sources in Asia, 8 in Europe, 1 from Australia, and 4 from North America, made up of administrative sources, health insurance records, registries, and a health survey.

In total, investigators identified 1 million deaths during 0.5 billion person-years of follow-up among people with diagnosed diabetes.

Additional analyses revealed:

• 17 of 19 data sources showed decreases in the age-standardized and sex- standardized mortality in people with diabetes, among which the annual percentage change in mortality ranged from –0.5% (95% CI, –0.7 to –0.3) in Hungary to –4.2% (95% CI, –4.3 to –4.1) in Hong Kong
• The largest decreases in mortality were observed in east and southeast Asia, with a change of –4.2% (95% CI, –4.3 to –4.1) in Hong Kong, –4.0% (95% CI, –4.8 to –3.2) in South Korea, –3.5% (95% CI, –4.0 to –3.0) in Taiwan, and –3.6% (95% CI, –4.2 to –2.9) in Singapore
• The annual estimated change in standardized mortality ratio (SMR) between people with and without diabetes ranged from –3.0% (95% CI, –3.0 to –2.9; US Medicare) to 1.6% (95% CI, 1.4-1.7; Lombardy, Italy)
• Among the 17 data sources with decreasing mortality among people with diabetes, a significant SMR increase was found in 5 data sources, no significant SMR change in 4 data sources, and a significant SMR decrease in 8 data sources
• Among the 17 data sources with decreasing mortality in people with diabetes, 16 had decreasing rates at most ages in both sexes
• Reduction in mortality in people with diabetes surpassed or was similar to the reduction in the population without diabetes in two-thirds of data sources examined

Of all the countries analyzed, data from Spain showed increases in mortality, while rates in Norway revealed a nonsignificant decrease. However, mortality rates did vary significantly between populations with diabetes. “For instance, in Catalonia, Spain, mortality in people with diabetes increased from approximately 2012 to 2016; however, mortality increased more rapidly in populations without diabetes (in both Catalonia and Spain),” authors wrote.

“Mortality rates are an important indicator of access to quality health care,” said study author Dianna Magliano, PhD, head of Diabetes and Population Health at the Baker Heart and Diabetes Institute in Melbourne, Australia. “Our findings suggest that we may be starting to reap the benefits of better education and disease management programs,” she noted.

Findings indicate improvements in diabetes care have been beneficial over time, although the analysis only included data from high-income countries. Authors described how increased screening rates and the introduction of universal health care and targeted intervention programs could have helped shape improved mortality rates seen in southeast Asian regions.

Overall, researchers hypothesized population-level health promotion on tobacco cessation and lifestyle modification to reduce diabetes risk factors contributed to the decrease seen in the majority of countries studied.

In the past few decades, the use of antihypertensive and lipid-lowering medications has also increased alongside more aggressive management of hypertension and hyperglycemia. “Earlier diagnosis of diabetes, with such changes particularly occurring in the late 1990s and early 2000s, might have facilitated earlier use of interventions with long-term benefits for survival,” authors added.

The lack of data obtained on diabetes treatment patterns and varied methods of diagnosing the disease throughout the world mark limitations to the study. Information on the age of diabetes diagnosis was also unavailable, meaning researchers could not investigate the association between mortality and disease duration.

“There is still a long way to go to control the many risks associated with diabetes, but these findings provide promising evidence that we are moving in the right direction,” said study co-author Jonathan Shaw, MD, a professor at Baker Heart and Diabetes Institute.

Reference

Magliano DJ, Chen L, Carstensen B, et al. Trends in all-cause mortality among people with diagnosed diabetes in high-income settings: a multicountry analysis of aggravate data. Lancet Diabetes Endocrinol. Published online January 10, 2022. doi:10.1016/S2213-8587(21)00327-2