Predictors of patient retention in a newly established methadone maintenance treatment programme

Aims. To identify predictors of patient retention in methadone maintenance. Design. Prospective study. Setting. Methadone maintenance treatment programme newly established in Geneva, Switzerland. Participants. All patients who initiated treatment between February 1991 and January 1995. Measurements. Baseline patient characteristics, dose of methadone, year of enrollment and retention in treatment. Findings. Overall, 111 patients contributed 164.4 person-years of follow-up. The retention rate was 84% after 12 months. In multivariate analysis, the risk of dropping out was significantly higher for patients who had been using opioids for 7 years (relative hazard (RH) 3.0, 95% confidence interval (CI) 1.2-7.4), and for patients who had no stable income at baseline (RH 3.3, 95% CI 1.2-9.1). Dropouts were less frequent at the highest doses of methadone (65-110 mg/day, RH 1.0) than at middle doses (45-60 mg/day, RH 2.0, 95% CI 0.7-5.5) but, quite unexpectedly, dropouts were least likely at the lowest doses (15-40 mg/day, RH 0.5, 95% CI 0.1-1.8). Dropouts were more likely among patients who enrolled in the first (RH 6.2, 95% CI 2.3-16.7) and second (RH 1.9, 95% CI 0.6-5.6) years of the programme, compared with subsequent years (RH 1.0). Conclusions. Patients who have a long history of drug use and who have a stable income were more likely to stay in methadone maintenance treatment. Independent of patient characteristics, retention improved dramatically in the first years of programme functioning, suggesting that patient retention is a sensitive indicator of programme performance.