Context Most research on heroin dependence treatments assesses short-term changes in patients' self-reported drug use. To our knowledge, long-term sustainability of changes in patients' drug use and associated hospital morbidity posttreatment have not been studied.
Objectives To evaluate drug-related hospital morbidity in heroin users at 6 months and 3
years after receiving naltrexone implant treatment and to compare these results with outcomes from a similar cohort treated with methadone maintenance treatment.
Design Retrospective longitudinal follow-up, using data prospectively collected via a state hospital (public and private) reporting system.
Setting Perth, Western Australia. Methadone maintenance dosage was generally dispensed daily by registered community pharmacies. Naltrexone implant treatment was performed as a day procedure at a community clinic.
Participants A total of 522 and 314 heroin-dependent persons (according to DSM-IV), first time treated with methadone maintenance or a naltrexone implant, respectively, between January 1, 2001, and December 30, 2002, were identified, using health record linkage.
Main Outcome Measures Planned outcomes included crude hospital admission rates, adjusted changes in risks (odds ratio [OR]), and rates (rate ratio) of "overdose-related" and "non–overdose-related" hospital morbidity associated with opioid vs nonopioid drugs 6 months and 3 years posttreatment.
Results Following naltrexone implant treatment, opioid-related risk decreased for overdose (OR, 0.23; 95% confidence interval [CI], 0.11-0.48) and nonoverdose (OR, 0.64; 95% CI, 0.46-0.89) conditions at 3 years. Such reductions were not observed after methadone treatment. Overdose on nonopioid drugs increased in older patients to 6 months: OR of 16.31 (95% CI, 3.07-86.53) for naltrexone and OR of 5.03 (95% CI, 1.18-21.54) for methadone. Nonoverdose (eg, dependence and withdrawal) associated with nonopioid drugs also increased for patients receiving the naltrexone implant: OR of 1.52 (95% CI, 1.04-2.23) at 3 years. In addition, there were 6 drug-related deaths: 5 after methadone maintenance and 1 after naltrexone implantation.
Conclusions Naltrexone implants, but not methadone maintenance, has long-term benefits in reducing opioid-related hospital morbidity. However, long-lasting and increased nonopioid drug–related morbidity following naltrexone implantation is particularly concerning. Similar studies are required to confirm these findings.
