Effectiveness of prize-based contingency management in a methadone maintenance program in China

Methadone maintenance treatment (MMT) has been successfully scaled up nationally in China. However, the program faces problems of poor attendance and high rates of continued drug use. We assessed whether a contingency management (CM) intervention implemented by MMT clinic staff could improve treatment attendance and drug abstinence.

Eight MMT clinics in Guangdong province were randomly selected and divided into two groups. A total of 126 participants (55 in urban clinics and 71 in rural clinics) received CM during a 12-week trial, 120 participants (83 in urban clinics and 37 in rural clinics) received usual treatment (UT). Participants in the CM group had the opportunity to draw for prizes contingent on attending treatment daily and testing negative for morphine. Clinic- and individual-level outcomes were compared between the intervention and control groups.

The retention rate and negative urine testing rate were 14.2% (P=0.010) and 10.7% (P<0.001) higher in the CM group compared to the UT group, respectively. Compared with participants who received UT, CM participants missed on average 7.3 fewer (P=0.008) visits and were 1.91 (95% CI: 1.53-2.39) times more likely to submit a negative urine sample. All clinic- and individual- level effects of the intervention were observed at rural clinics, but the difference in retention rate between urban CM and UT clinics was not significant.

Although the frequency of monitoring and value of the incentives in this study was lower than in previous studies, the CM intervention significantly improved attendance and reduced drug use in China.