Evaluating the impact of community-based treatment options on methamphetamine use: findings from the Methamphetamine Treatment Evaluation Study (MATES)

Aims: To evaluate the impact of community-based drug treatment on methamphetamine use using inverse probability of treatment-weighted (IPTW) estimators to derive treatment effects. Design: A longitudinal prospective cohort study with follow-ups at 3 months, 1 year and 3 years. Treatment effects were derived by comparing groups at follow-up. IPTW estimators were used to adjust for pre-treatment differences between groups. Setting: Sydney and Brisbane, Australia. Participants: Participants were methamphetamine users entering community-based detoxification (n=112) or residential rehabilitation (n=248) services and a quasi-control group of methamphetamine users (n=101) recruited from the community. Measurements: Frequency of methamphetamine use between interviews (no use, less than weekly, 1-2 days per week, 3+ days per week), continuous abstinence from methamphetamine use, past month methamphetamine use and methamphetamine dependence. Findings: Detoxification did not reduce methamphetamine use at any follow-up relative to the quasi-control group. Relative to quasi-control and detoxification groups combined, residential rehabilitation produced large reductions in the frequency of methamphetamine use at 3 months [odds ratio (OR)=0.23, 95% confidence interval (CI) 0.15-0.36, P