Excess Mortality in an Inception Cohort of Childhood Diabetes Diagnosed 1990–2010

Objective. Evaluate the mortality risk of childhood-onset type 1 diabetes compared to the general population. Research Design and Methods. The study population, identified from the Australasian Paediatric Endocrinology Group diabetes register, was diagnosed with type 1 diabetes at age < 16 in New South Wales (NSW), Australia, from 1990 to 2010. The register was linked to National Death Index registrations to ascertain timing and cause of death up to 31/12/2022. Risk factors for mortality were assessed using multivariable Cox regression models and observed mortality rate compared to “expected” rates in the Australian general population using indirect-standardized mortality ratios (SMR), overall and by sex and age at diagnosis. Diabetes-related cause of death categories were identified. Results. Of 5,417 children diagnosed with type 1 diabetes, 157 subsequently died, with all-cause mortality of 1.37/1,000 person years. Increased mortality risk was associated with living in most disadvantaged areas (aHR 1.81 (1.05, 3.11)) but not living in a rural area. Overall SMR was 2.83 (95% CI 2.40, 3.33) with females having higher SMR than males (4.18 vs. 2.19). Most common causes of death recorded were acute diabetes complications (26%), including diabetes ketoacidosis, accident/misadventure (21%), and chronic diabetes complications (15%). Alcohol and/or drug use contributed to 17% of deaths. Conclusion. Compared to the general population, higher risk of mortality in people with type 1 diabetes was associated with female sex and living in area of socioeconomic disadvantage. Education about minimizing risk-taking behaviors should be communicated to young adults with type 1 diabetes.