Mortality among individuals with cannabis, cocaine, amphetamine, MDMA, and opioid use disorders a nationwide follow-up study of Danish substance users in treatment.
This is a register-based cohort study of 20,581 individuals in treatment for illicit substance use disorders in Denmark between 1996 and 2006. All in all, 1441 deaths were recorded during 111,445 person-years of follow-up. Standardized mortality ratios (SMRs) associated with different primary substance types were calculated and Cox-regression analyses were performed in order to establish hazard ratios (HR) associated with injection drug use and psychiatric comorbidity. SMRs for primary users of specific substances were cannabis 4.9 (95% confidence interval (CI) 4.2-5.8), cocaine 6.4 (CI 3.9-10.0), amphetamine 6.0 (CI 4.2-8.3), heroin 9.1 (CI 8.5-9.8), and other opioids 7.7 (CI 6.6-8.9). For MDMA (ecstasy) the crude mortality rate was 1.71000 person-years (CI 0.4-7.0) and the SMR was not significantly elevated. Injection drug use was associated with significantly increased hazard ratios in users of opioids and cocaineamphetamine. Overall, psychiatric comorbidity was not associated with increased mortality (HR 1.1 CI 0.9-1.2, p.28), but an association was found specifically among cocaineamphetamine users (HR 3.6 CI 2.1-6.4, p<.001).