Objective: To examine mortality rates and causes of death among subjects diagnosed with type 1 diabetes aged <or=29 years.
Research design and methods: Subjects with type 1 diabetes from a population-based register in Yorkshire, U.K., diagnosed between 1978 and 2004 were linked to the U.K. National Health Service Central Register for death notifications. Deaths were coded using ICD-9 (1979-2000) and ICD-10 (2001-2005). Standardized mortality ratios (SMRs) were calculated using expected numbers of deaths from U.K. mortality rates by cause of death and age at diagnosis.
Results: A total of 4,246 individuals were followed up, providing 50,471 person-years of follow-up. Mean follow-up length was 12.8 years for individuals aged 0-14 years and 8.3 for those aged 15-29 years. Overall, 108 patients died, of whom 77 (71%) were male. A total of 74 (1.7/1,000 person-years) deaths occurred in inidividuals aged 0-14 years and 34 (4.6/1,000 person-years) in those aged 15-29 years. The SMR was 4.7 (95% CI 3.8-5.6) overall, similar for males and females, but higher for individuals aged 15-29 years (SMR 6.2 [95% CI 4.3-8.6]) compared with those aged 0-14 years (4.2 [3.3-5.3]). The SMR rose with increasing disease duration. A total of 47 of 108 deaths (44%) occurred from diabetes complications, 32 of which were acute and 15 chronic. Twenty-two percent (n = 24) of deaths were attributed to accidents or violence (SMR 2.1 [95% CI 1.4-3.2]), including six suicides. Sixteen percent of all deaths were related to drug misuse (including insulin but excluding tobacco and alcohol) (SMR 6.4 [95% CI 3.7-10.2]).
Conclusions: Subjects with type 1 diabetes diagnosed under 30 years of age had a 4.7-fold excess mortality risk. Nearly half of the deaths were due to acute or chronic complications of diabetes. Drug misuse-related deaths may be an emerging trend in this population warranting further investigation.