Objective: We analyzed a 6-year methadone maintenance treatment (MMT) retention rate in 8 MMT clinics in Xi'an and the factors that influenced the retention rate.
Methods: We conducted a 6-year retrospective dynamic cohort study of 5849 eligible patients from 2006 to 2011. Participants were serially enrolled on the basis of opioid addiction, age, residence status, and civil capacity. Cumulative retention in treatment was calculated using survival analyses (life tables) on the basis of the number of days in MMT. We also used the Cox proportional hazard regression model to analyze the factors that may influence treatment retention.
Results: The MMT retention varied from a less than 1 month to a maximum of 71.2 months; the average dose was 48.76 ± 17.03 mg/d. The cumulative retention for 12, 24, 36, 48, 60, and 72 months after MMT initiation were 0.87, 0.76, 0.66, 0.57, 0.49, and 0.43, respectively. The MMT retention rate was significantly associated with factors that included the particular clinic for MMT, the year when the subject initiated MMT, average daily dose, hidden drug use, sex, age, length of drug abuse history, needle sharing, living arrangements, and employment status.
Conclusions: The 6-year retention rates for MMT in the 8 clinics in Xi'an were higher than those reported in other studies of other clinics. High therapeutic doses (>60 mg/d) could reduce the risk of patients withdrawing from treatment. Retention rates were relatively high in cohorts who were elderly, living with family, employed, or drug users, especially those with a long history of drug abuse.