Retention in treatment of heroin users in Italy: the role of treatment type and of methadone maintenance dosage.

Retention in treatment among 1503 heroin users attending public treatment centres in 1995 was studied. Three different treatments were considered: methadone maintenance, drug-free program and naltrexone. The retention rate after 1 year was 40% for patients in methadone maintenance, 18% in naltrexone and 15% in drug-free program. For patients in maintenance, methadone dosage and clinic policy were the most important factors for retention. Patients taking > or = 60 mg/day and 30-59 mg/day were respectively 70 and 50% more likely to remain in treatment than those receiving a < 30 mg daily dose. Patients in maintenance-oriented clinics were 30% more likely to remain in treatment than those in abstinence-oriented centres.