One-year and cumulative retention as predictors of success in methadone maintenance treatment: a comparison of two clinics in the United States and Israel

Abstract

Outcome predictors between two methadone maintenance treatment clinics in Tel-Aviv, Israel, and Las Vegas, Nevada, were determined by comparing patients' characteristics. All patients admitted to the two clinics (302 from Las Vegas and 492 from Tel-Aviv) were studied with respect to variables at admission and follow-up. Las Vegas patients were older, contained more females, had more hepatitis C positive markers, and more urine analyses that were positive for cocaine, amphetamines, and tetrahydrocannabinol (THC) on admission than the Tel-Aviv patients. After 1 year, Tel-Aviv patients had higher retention (73.6% vs. 61.6%) and similar opiate abstinence (65.8% vs. 64.9%) compared to Las Vegas patients. Predictors for cumulative retention (Cox regression) for both clinics were higher methadone dosages greater than or equal to 100 mg/day (Tel-Aviv OR [odds ratio] = 2.1, 95% confidence interval [CI] = 1.6-2.9; Las Vegas OR = 1.8, 95% CI = 1.3-2.5). Also, in Tel-Aviv, predictors were no opiate use after 1 year (OR = 1.7, 95% CI = 1.4-2.2) and no benzodiazepine after 1 year, and in Las Vegas no cocaine and no amphetamines after 1 year and age less than or equal to 30 years. The two major predictors in the two clinics were successful in both outcomes: 1 year retention and opiate abstinence.

FIGURE 1

The cumulative retention in treatment for patients from Tel-Aviv and Las Vegas MMT Adelson clinics. Censored patients from both clinics are marked. Duration (in years) in clinic from first admission until the patient quit treatment or until the end of the follow-up (5.3 years in both Las Vegas and Tel-Aviv, despite the fact that 11 years of follow-up data are available and have been published for Tel-Aviv alone was taken for calculating cumulative retention in treatment using survival analyses (Kaplan-Meier) with log rank.