Cost-effectiveness of paying drug users to abstain
- Presenter:
Chair: Jose Escarce; Discussant: Anthony Lo Sasso Mon June 5, 2006 15:30-17:00 Room 225
We analyze the cost-effectiveness of a novel approach to treating drug abuse that pays drug users not to use drugs. In this approach, drug users in treatment programs are tested and paid small incentives when they abstain from using specific drugs. The standard approach of such a Contingency Management (CM) approach is to pay fixed increments on an escalating basis. The CM under study is a lower cost prize-based version of in which instead of earning fixed awards, the successful patient draws chips from an urn. The chips indicate whether or not a prize has been won and the exact prize. The prize value and probability of winning each type of prize can be varied so that the expected value of payments can be varied. With increased abstinence, the patient gets to take more draws and the number of draws increases at an escalating rate to encourage longer term abstinence.
The effectiveness data were obtained from the Motivational Incentives-Drug Free Clinics study conducted in the context of the National Drug Abuse Treatment Clinical Trials Network. Patient outcome measures include total number of stimulant-negative urine samples provided and longest duration of confirmed stimulant abstinence. The cost data were obtained via surveys sent to the eight participating psychosocial drug abuse treatment clinics. Patients (N = 412) were randomly assigned within each clinic to usual care (UC) or usual care plus contingency management (CM). Clinic costs included: counseling, patient drug testing, and administration of the incentives component (value of prizes, administrative time to draw prizes, and administrative time to inventory, shop, and stock prizes).
Results are presented for the incremental cost-effectiveness ratios (ICERs) of CM relative to UC for all sites combined, as well as for each site separately. A special emphasis of this cost-effectiveness analysis was on the multi-site nature of the trial and the interpretation of the site differences. The study determined that the ICER for an additional stimulant-negative urine sample was $131 per additional negative urine sample for all sites combined, and ranged by site from $74 to $252 across the sites. The ICERs for lengthening the longest duration of confirmed stimulant abstinence by one week were also varied across the sites. In addition, scatterplots of the bootstrapped replicates and the corresponding acceptability curves were presented to illustrate the uncertainty inherent in the incremental cost-effectiveness ratios (ICERs) and to provide policy relevant interpretation of the ICERs. The overall and site-by-site scatterplots of the ICERs and the acceptability curves are provided. We discuss external data that can be brought to bear regarding the policy interpretation of the ICERs, e.g. what is the value gained in terms of crimes and spread of disease averted by lengthening longest duration of abstinence and a greater number of negative drug urine tests? We also discuss a variety of policy, implementation and equity issues regarding the wider spread adoption of this novel treatment.
