Transcript Open slides - CTN Dissemination Library

Abstinence Incentives for Methadone
Maintained Stimulant Users:
Outcomes for Those Testing Stimulant
Positive vs Negative at Study Intake
Maxine L. Stitzer
Johns Hopkins Univ SOM
National Drug Abuse Treatment Clinical Trials
Network MIEDAR Study Team
Acknowledgements
• NIDA CTN for funding
• MIEDAR study team for successful conduct
and reporting of the multi-site study
• Financial disclosures: none
Background
• Motivational incentives (e.g. prizes) promote
behavior change (e.g. drug abstinence)
• Efficacy demonstrated across a number of
abused drugs (alcohol, cannabis, cocaine,
opiates,)
• Effectiveness demonstrated in large sample CTN
multi-site study focusing on stimulant abusers in
psychosocial counseling (Petry et al., 2005) and
methadone maintenance (Peirce et al., 2006) treatment
Differential Response to
Incentives
• Not everyone benefits from abstinence
incentives
• In meth patients, response to incentives
related to pre-study drug use (less use =
better response)
– (Preston et al., 1998; Silverman et al., 1998)
• Not known whether response is confined to
lower severity users
Objective
• Examine overall impact of baseline stimulant
use severity on treatment outcome using CTN
data from the methadone maintained sample
• Determine whether incentive effects differ for
those with higher and lower stimulant use
severity
CTN Study Methods
• Methadone patients (N = 388) - stabilized w/
mean dose of 86mg and mean of 9 months in
treatment at study entry
• Random assignment to usual care with or
without incentives; 12-week evaluation
• “Fishbowl” incentive method used
– Stimulant-negative urines (2/wk) earned prize
drawings under escalating schedule
– 50% chance of earning a prize (range in value $1$100; inverse relationship for value and probability)
Defining Drug Use Severity
• Regression analysis indicated that intake
urine test result (stimulant pos/neg) was
strongest predictor of outcomes among 20
variables examined (R2 = .26)
• Present analysis stratifies on study intake
urine test result (stim positive vs negative)
Participant Characteristics
% female
% white
% > 40
% employed
Stim Pos
(N = 292)
Stim Neg
(N = 94)
47
24
62
31
34
34
54
33
% with drug dependence diagnosis
stimulant
88
alcohol
15
cannabis
10
66
22
3
Follow-up Analysis
• Stratified analysis with 2 grouping variables
– stimulant positive vs. negative urine sample at
study intake
– Incentive versus control condition
• Outcome measures:
– Study retention (survival analysis)
– Percent of stimulant-negative urine samples
(General Estimating Equation; GEE)
Study Retention (effects ns)
Effect of Intake Urine Test Result
on Overall Stimulant Use
incentive and control groups collapsed
Stimulant negative at intake n=94
100
Stimulant Positive at intake n =292
80
60
40
20
OR = 8.7 CI = 5.8 - 12.9)
0
1
2
3
4
5
6
7
8
Study Weeks
9
10 11 12
Incentive Effects in Those Stimulant
Positive vs Negative at Intake
Stimulant Positive (N = 292)
Stimulant Negative (N = 94)
100
100
Incentive
Usual Care
80
80
60
60
40
40
20
20
OR = 2.27
(1.13-4.17)
OR = 1.84
(1.25-2.71)
0
0
2
4
6
8
Study Weeks
10
12
2
4
6
8
Study Weeks
10
12
Summary
• Intake drug use severity is predictive of overall
treatment outcome (negative urine ---->
relatively better outcomes)
• Incentives reduced stimulant use during
treatment independent of intake urine test
result
• Similar OR’s suggest similar benefit magnitude
despite different baseline rates of drug use
Discussion
• Results highlight prognostic importance of
obtaining and attending to during-treatment
urinalysis results
• Study adds to literature on generality of
outcome in an abstinence incentive program
• Conclude incentives can be offered to all
methadone maintained stimulant abusers to
improve outcomes irrespective of use severity