To characterize the burden of external causes of death attributable to alcohol-related causes, accidents and suicide among diabetic patients in a large national cohort.
The population included diabetic individuals who had purchased and received reimbursement for at least one insulin prescription and/or one oral antidiabetic drug prescription between January 1997 and December 2010, and a non-diabetic reference population matched by sex, age and area. All new insulin users in this period were included, as well as 50% of new oral drug (OAD) users as a random sample. The data were collected by means of linkage from national registries. We analyzed the cohort data using Poisson regression models separately for each end-point and by gender (mortality rate ratio (MRR)). We subjected the case-cohort data to conditional logistic regression analysis based on exposure information within 1 year of the end-point event. The follow-up started on the date of the first diabetes medication prescription and ended on 31 December 2012 or on the date of death.
The study population comprised 434 629 individuals (226 372 men; diabetes population: 208 148 subjects, of whom 76% were treated only with OAD). The mean follow-up time was 7.1 years, during which there were 2832 deaths attributable to alcohol, 3187 to accidents and 853 to suicide. The diabetic subjects had higher mortality at almost all end-points, especially those treated with insulin: the adjusted MRRs for alcohol-related deaths were 1.71 for diabetic men treated with OAD and 6.92 for those on insulin; the respective MRRs for diabetic women were 2.10 and 10.60. There were more accident-related deaths among those treated with insulin (MRRs: 2.06 and 1.53 for men and women, respectively), and more suicides (MRR: 2.10 for men treated with insulin and 1.62 among women treated only with OAD). The results from the cohort study and the case-cohort study were rather similar. A time-dependent effect of diabetes was observed in alcohol-related mortality among men.
The findings from this large nationwide cohort indicate higher mortality attributable to suicide, alcohol-related causes and accidents among diabetic patients than among the non-diabetic population. The results emphasize the importance of effective psychosocial interventions among high-risk diabetic patients.