Life expectancy of type 1 diabetic patients during 1997–2010: a national Australian registry-based cohort study

Lili Huo, Jessica L. Harding, Anna Peeters, Jonathan E. Shaw, Dianna J. Magliano

There is limited information about the impact of type 1 diabetes on life expectancy in a contemporary population. We examined the life expectancy of type 1 diabetic patients and explored the contribution of mortality at different ages and of different causes of death to years of life lost (YLL) compared with the general population. We derived mortality rates of Australians with type 1 diabetes listed on the National Diabetes Services Scheme (NDSS) between 1997 and 2010 (n = 85,547) by linking the NDSS to the National Death Index. The Chiang method was used to estimate life expectancy and Arriaga's method was used to estimate the contributions of age-specific and cause-specific mortality to the YLL. A total of 5,981 deaths were identified during the 902,136 person-years of follow up. Type 1 diabetic patients had an estimated life expectancy at birth of 68.6 years (95% CI 68.1, 69.1), which was 12.2 years (95% CI 11.8, 12.7) less than that in the general population. The improvement in life expectancy at birth in 2004-2010 compared with 1997-2003 was similar for both type 1 diabetic patients (men, 1.9 years [95% CI 0.4, 3.3]; women, 1.5 years [95% CI 0.0, 3.2]) and the general population (men, 2.2 years; women, 1.4 years). Deaths at age <60 years accounted for 60% of the YLL from type 1 diabetes for men and 45% for women. The major contribution to YLL was mortality from endocrine and metabolic disease at age 10-39 years (men, 39-59%; women, 35-50%) and from circulatory disease at age ≥40 years (men, 43-75%; women, 34-75%). Data from 1997 to 2010 showed that Australian type 1 diabetic patients had an estimated loss in life expectancy at birth of 12.2 years compared with the general population.