Abstinence Incentives for Methadone Maintained Stimulant Users: Outcomes for Those Testing Stimulant Positive vs Negative at Study Intake

1
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

2
Acknowledgements

• NIDA CTN for funding
• MIEDAR study team for successful conduct and
  reporting of the multi-site study
• Financial disclosures none

3
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

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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

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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

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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)

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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)

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Participant Characteristics
Stim Pos Stim Neg (N 292)
(N 94) female 47 34 white
24 34 gt 40 62
54 employed 31 33 with drug
dependence diagnosis stimulant
88 66 alcohol 15
22 cannabis 10 3

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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)

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Study Retention (effects ns)
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Effect of Intake Urine Test Result on
Overall Stimulant Use incentive and
control groups collapsed
Stimulant negative at intake n94
100
Stimulant Positive at intake n 292
80
60
Percentage of Samples Stimulant Negative
40
20
OR 8.7 CI 5.8 - 12.9)
0
1
6
7
8
9
10
11
12
4
2
3
5
Study Weeks
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
Percentage of Samples Stimulant Negative
40
40
20
20
OR 1.84 (1.25-2.71)
OR 2.27 (1.13-4.17)
0
0
8
10
12
2
6
2
10
12
4
6
8
4
Study Weeks
Study Weeks
13
Good outcome was associated with lower severity
drug use
Outcome Number Stimulant Neg Stim
Neg Urines Sample Size At
Entry 0 110 0 1-6 124
22 7-18 95 33 19-24
57 63
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Summary

• Intake drug use severity is predictive of overall
  treatment outcome (negative urine ----gt
  relatively better outcomes)
• Incentives reduced stimulant use during treatment
  independent of intake urine test result
• Similar ORs suggest similar benefit magnitude
  despite different baseline rates of drug use

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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