Mortality in a cohort of opiate and amphetamine users in Perth, Western Australia.

Aims: This study compares the hazard of death among opiate and amphetamine using clients who accessed drug treatment with individuals who had no specialist treatment contact between 1985 and 1998.

Design, Setting, Participants: This was a retrospective cohort study of 4280 drug-using individuals (2887 opiate users, 1393 amphetamine users) admitted to Perth metropolitan hospitals or Perth psychiatric institutions between 1985 and 1998. Of these, 1469 attended Next Step Specialist Drug and Alcohol Services (928 received methadone and 541 attended counselling or support groups) and 2811 had no contact with this service.

Methods: Data from two drug treatment programmes were linked with hospital morbidity, psychiatric services and the mortality database using record linkage.

Findings: The results show that people who were currently in drug treatment had a lower hazard of death compared with non-clients and those who had ceased treatment. Those who had ceased treatment more than 6 months ago had 7.0 times the hazard of all-cause death and 8.4 times the hazard of drug-cause death. Opiate users were at 1.4 times the hazard of all-cause death and 2.4 times the hazard of drug-cause death compared with amphetamine users. Males were at 1.79 times the hazard of all-cause death and, unexpectedly, were found to be at 2.69 times the hazard of drug-cause death compared with females.

Conclusions: Treatment protected clients from premature death compared with people who did not receive treatment and also those who ceased treatment. While amphetamine users had a lower risk of mortality compared with opiate users, the full extent of the relationship between amphetamine use and mortality needs to be examined further.