Improvements in the life expectancy of type 1 diabetes: the Pittsburgh Epidemiology of Diabetes Complications study cohort

Abstract

Survival in type 1 diabetes has improved, but the impact on life expectancy in the U.S. type 1 diabetes population is not well established. Our objective was to estimate the life expectancy of the Pittsburgh Epidemiology of Diabetes Complications (EDC) study cohort and quantify improvements by comparing two subcohorts based on year of diabetes diagnosis (1950-1964 [n = 390] vs. 1965-1980 [n = 543]). The EDC study is a prospective cohort study of 933 participants with childhood-onset (aged <17 years) type 1 diabetes diagnosed at Children's Hospital of Pittsburgh from 1950 to 1980. Mortality ascertainment was censored 31 December 2009. Abridged cohort life tables were constructed to calculate life expectancy. Death occurred in 237 (60.8%) of the 1950-1964 subcohort compared with 88 (16.2%) of the 1965-1980 subcohort. The life expectancy at birth for those diagnosed 1965-1980 was ~15 years greater than participants diagnosed 1950-1964 (68.8 [95% CI 64.7-72.8] vs. 53.4 [50.8-56.0] years, respectively) (P < 0.0001); this difference persisted regardless of sex or pubertal status at diagnosis. This improvement in life expectancy emphasizes the need for insurance companies to update analysis of the life expectancy of those with childhood-onset type 1 diabetes because weighting of insurance premiums is based on outdated estimates.

FIG. 1.

Observed Kaplan-Meier survival function comparing EDC study type 1 diabetes diagnosis year subcohorts (1950–1964 vs. 1965–1980) and the ACR cohort. The small vertical lines represent censoring times of surviving individuals. EDC 1950–1964 vs. 1965–1980 log-rank P < 0.0001; EDC 1965–1980 vs. ACR log-rank P = 0.10. Remaining number at risk at each age: EDC 1950–1964: birth, 390; 20 years, 370; 40 years, 239; 60 years, 26; EDC 1965–1980: birth, 543; 20 years, 537; 40 years, 272; 60 years, 0; ACR: birth, 1,018; 20 years, 1,002; 40 years, 704; 60 years, 0.