Life Expectancy Gap Between Patients With Type 1 Diabetes and General Population Persists

Although life expectancy has increased among patients with type 1 diabetes and the general population, those with the disease are still likely to live more years with disabilities and die earlier than people without diabetes.^1,2,3,4

According to a study published in JAMA in 2015, the estimated loss of life expectancy in patients with type 1 diabetes at 20 years of age was approximately 11 years for men and 13 years for women, as compared with the general population without the disease.¹ The findings were based on data from patients in Scotland from 2008 to 2010. Nevertheless, the researchers noted that their findings may not hold true for other nations or populations.

“An important question is whether our findings are generalizable internationally. This cannot be directly assessed because there are no large contemporary or historical nationally representative studies from other countries,” Shana Livingston, MSc, of the University of Dundee in Scotland, and colleagues wrote, noting that contemporary larger scale data from other countries are needed.

However, 2 recent studies published in Diabetologia, which examined life expectancy of patients with type 1 diabetes in Australia and Sweden, may offer a few answers to this question.

Data From Australia

In the first study, Lili Huo, MD, and Dianna Magliano, PhD, both from Baker IDI Heart and Diabetes Institute in Melbourne, Australia, derived mortality rates of Australians with type 1 diabetes listed on the National Diabetes Services Scheme between 1997 and 2010 (n=85 547). They then estimated life expectancy and the contributions of age-specific and cause-specific mortality to the years of life lost.

During 902 136 person-years of follow-up, 5981 deaths occurred. Estimated life expectancy at birth for patients with type 1 diabetes was 68.6 years (95% confidence interval [CI], 68.1-69.1).² Similar to the study conducted by Livingstone et al, this translated to an estimated loss of life expectancy of 12.2 years (95% CI, 11.8-12.7) compared with the general population.²

The researchers also reported that when assessed according to sex, men with type 1 diabetes had a life expectancy at birth of 66.7 years (95% CI, 66.1-67.5) and could expect to live 11.6 years (95% CI, 10.9-12.2) less than the general population.² Likewise, women with type 1 diabetes had a life expectancy at birth of 70.9 years (95% CI, 70.3-71.7) and could expect to live 12.5 years (95% CI, 11.7-13.1) less than the general population.²

As people aged, the reduction in life expectancy gradually decreased for both sexes.

The researchers noted that improvements in life expectancy for patients with type 1 diabetes were comparable to those seen for the general population over the 14-year follow-up. Specifically, estimated life expectancy at birth increased by 1.9 years (95% CI, 0.4-3.3) for men and 1.5 years (95% CI, 0.0-3.2) for women from the time periods 1997-2003 to 2004-2010.² In the general population, improvements of 2.2 years and 1.4 years were seen for men and women, respectively.²

Results revealed that among men, deaths before 40 and 60 years of age accounted for 21.1% and 60.2%, respectively, of the total years of life lost.² Among women, deaths before age 40 and 60 contributed to 15.1% and 45.4%, respectively, to the total years of life lost.²

Circulatory disease was the leading cause of death in patients with type 1 diabetes, accounting for 37.5% of all deaths and for almost half of all years of life lost.² For patients older than 40, it accounted for 40% to 60% of deaths.²