Predictors of methadone treatment retention from a multi-site study: a survival analysis

Longer tenure in methadone treatment has been associated with positive outcomes such as reductions in drug use and crime, HIV seroconversion, and overdose death.

Retention in treatment was examined for 351 opioid-dependent individuals who had been newly admitted to one of six methadone programs in Baltimore, Maryland. Cox proportional hazards regression was used to predict number of days retained in treatment to 90 days from baseline ASI Composite scores and Treatment Motivation scales. A second analysis predicted days in treatment to 365 days using the same baseline variables plus 3-month Motivation scales, Patient Satisfaction scales, and methadone dose in the 248 individuals who had remained in treatment at least 3 months. Analyses held constant gender, race, age, whether participants had a history of regularly smoking cocaine, whether participants were on parole/probation, and program site.

Retention at 90 days was predicted by female gender, and greater baseline Treatment Readiness (p=.005) but lower Desire for Help (p=.010). Retention at 365 days was predicted by higher baseline ASI Medical Composite scores (p=.037) and lower Legal Composite scores (p=.039), higher 3-month Treatment Satisfaction scores (p=.008), and higher dose (p=.046).

Greater satisfaction with treatment at 3 months was a significant predictor of retention at 12 months, indicating the importance of understanding the role satisfaction plays in determining retention. Greater severity of legal problems was associated with shorter retention, suggesting that program efforts to increase services to criminal justice patients (e.g., legal counseling) may constitute a useful addition to treatment.