Causes of premature mortality in Swedish drug abusers: A prospective longitudinal study 1970–2006

Abstract

Aims To evaluate premature mortality and causes of death from young adulthood to middle age in a cohort of drug users followed during almost four decades Design Follow-up study of a consecutive cohort of patients with drug abuse/dependence. Methods A cohort of 561 drug abusers, admitted to a detoxification and short-term rehabilitation unit 1970–1978 was followed to December 31st, 2006. Standardized interviews and hospital records with toxicological analyses were used for demographic data, substance use and psychiatric diagnoses at admission. For Follow-up analyses, autopsy protocols including toxicology tests and death certificates were obtained for assessment of causes of death which were coded according to ICD-10. Age-group standardized mortality ratios were calculated independently for both sexes. Results 204 persons (36.4%) were deceased by 2006. SMR was 5.94 for the cohort. Compared to an age- and gender-matched population, the risk of premature death was about eighteen times higher between the ages of 20–44 and about five times higher from 45 up to the age of 69. Of 120 (59%) drug-related deaths, 43 were opiate overdoses, and 3 were overdose from amphetamine. A total of 53 (26%) persons died violent deaths: 39 suicides, of which 25 were drug-related, 3 homicides and 12 accidents. The Swedish national causes of death register underestimated drug-related death by 37% and suicide by 85% compared to the results from this study. Conclusions The cohort of drug abusers had an increased risk of premature often drug-related and violent death well into middle age, and to a great extent the drug addicts died from the same drug they had abused when they were first admitted for treatment. The underestimation of drug-related death and suicide in some national death cause registers could be reduced if the doctor routinely records ICD codes when issuing death certificates and autopsy protocols.