15-Year survival and retention of patients in a general hospital-affiliated methadone maintenance treatment (MMT) center in Israel

We have extended our previous 10-year follow-up study of MMT retention for another 5 years and added data on survival of all patients ever admitted to our MMT clinic (6/1993 to 6/2007). Data were calculated from admission to MMT until leaving, death, or study closure (6/2008). Ninety-four of a total of 613 patients (4711.6 person-years [py]) died. Cancer was the primary cause of death for those who remained in treatment, and overdose for those who left MMT. Longer survival (p=0.051) with a trend for a lower mortality rate (p=0.08) was noted among the 464 patients who stayed in treatment ≥1 year (1.8/100 py), compared with the 149 patients who left MMT <1 year (2.6/100 py). Predictors of survival in multivariate analyses were younger age (<40 years) at admission, living with a spouse/partner, being hepatitis B sera-negative, not abusing benzodiazepines on admission (interaction effect), not being referred directly from hospitalization to MMT, and not leaving the MMT program for hospitalization. The two latter variables also predicted longer retention, as did a high methadone dose (≥100 mg/d), no opiate and, no benzodiazepine abuse after 1 year and either having any DSM-IV-TR Axis I, or no Axis I&II psychiatric diagnoses. Unlike retention, mortality was associated with pre-treatment severity and comorbidities thus only partially reflects MMT outcome (opiate abstinence and treatment success). Benzodiazepine abuse reduced both retention and survival, emphasizing the high priority that should be given to stopping it.