Temporal trends in the survival of drug and alcohol abusers according to the primary drug of admission to treatment in Spain.

BACKGROUND: Mortality of alcohol and drug abusers is much higher than the general population. We aimed to characterize the role of the primary substance of abuse on the survival of patients admitted to treatment and to analyze changes in mortality over time.

METHODS: Longitudinal study analyzing demographic, drug use, and biological data of 5023 patients admitted to three hospital-based treatment units in Barcelona, Spain, between 1985 and 2006. Vital status and causes of death were ascertained from clinical charts and the mortality register. Piecewise regression models were used to analyze changes in mortality.

RESULTS: The primary substances of dependence were heroin, cocaine, and alcohol in 3388 (67.5%), 945 (18.8%), and 690 patients (13.7%), respectively. The median follow-up after admission to treatment was 11.6 years (IQR: 6.6-16.1), 6.5 years (IQR: 3.9-10.6), and 4.8 years (IQR: 3.1-7.8) for the heroin-, cocaine-, and alcohol-dependent patients, respectively. For heroin-dependent patients, mortality rate decreased from 7.3×100person-years (p-y) in 1985 to 1.8×100p-y in 2008. For cocaine-dependent patients, mortality rate decreased from 10.7×100p-y in 1985 to <2.5×100p-y after 2004. The annual average decrease was 2% for alcohol-dependent patients, with the lowest mortality rate (3.3×100p-y) in 2008.

CONCLUSIONS: Significant reductions in mortality of alcohol and drug dependent patients are observed in recent years in Spain. Preventive interventions, treatment of substance dependence and antiretroviral therapy may have contributed to improve survival in this population.