Alcohol Drinking, Veterans
Conditions
Brief summary
Alcohol contributes to 88,000 deaths and costs an estimated $223 billion annually in the United States. Alcohol use disorder (AUD) is highly prevalent in veterans. The positive public health impact of reducing heavy drinking among veterans with AUD would prevent significant medical morbidity and mortality. Contingency management (CM) is an intensive behavioral therapy that provides incentives to individuals for reducing substance use. Monitoring alcohol abstinence usually requires daily monitoring. Because of this difficulty, CM approaches for treatment of AUD are not currently available to people with AUD. Our group has developed a mobile smart-phone application that allows patients to video themselves using an alcohol breath monitor and transmit the encrypted data to a secure server. This innovation has made the use of CM for outpatient AUD treatment feasible. The aim of the current study is to evaluate the effectiveness and cost effectiveness of CM as an add-on to cognitive behavioral therapy for AUD. The trial will also explore the potential usefulness of a long-term abstinence incentive ontreatment utilization and alcohol outcomes. Proposed is a trial in which 140 veterans with AUD will be randomized to receive either CM as an add-on to evidence-based CBT or CBT alone. Veterans will also be randomized to one of two long-term incentive conditions (i.e., receipt of a monetary incentive for abstinence/low-risk drinking at 6- months vs. no incentive). This project aims to advance AUD treatment by 1) testing the effectiveness of a mobile health approach that makes CM for AUD feasible, and 2) providing highly needed cost-effectiveness data on the use of behavioral incentives as an adjunct to CBT for the treatment of AUD. These aims are designed to address two significant barriers to the implementation of CM for AUD.
Interventions
BEHAVIORALCognitive Behavioral Therapy (CBT)
Twelve in-person counseling sessions designed to assist participants with becoming abstinent from alcohol use (or reduce use).
BEHAVIORALMobile Contingency Management (mCM)
Abstinence (measured by breath alcohol) will be intermittently reinforced. For each breath alcohol concentration reading that tests negative, a participant will earn a virtual scratch-off lottery ticket that contains 100 different values.
BEHAVIORALLong-term incentive
This incentive is $300 for self-reported and bioverified 30-day abstinence from heavy drinking at the follow-up scheduled for 6-months after the initial quit date
Sponsors
Duke University
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* are an enrolled veteran at the DVAHCS for primary care, * have current AUD (meeting past month DSM-5 criteria), and * are willing to make a quit attempt and/or reduce alcohol use to low risk levels.
Exclusion criteria
* have fewer than 3 days of abstinence, * have a history of clinically significant alcohol withdrawal, as indicated by a score of 10 or more on the Clinical Institute Withdrawal Assessment of Alcohol (CIWA), or * are currently receiving professional behavioral treatment for AUD.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Average Number of Heavy Drinking Days | 6-month post quit visit | At the 6-month follow-up visit, participants will self-report the number of heavy drinking (\> 5 drinks in day for men, \> 4 drinks in a day for women) days they have had in the past thirty days. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Average Number of Binge Drinking Days | 6-month post quit visit | Participants will self-report the number of binge drinking (heavy drinking within a 2-hour period) days in the past thirty days. |
| Average Number of Drinking Days | 6-month post quit visit | Participants will self-report the number of drinking days in the past thirty days. |
| Average Number of Drinks Per Drinking Day | 6-month post quit visit | Participants will self-report the number of drinks on drinking days in the past 30 days. |
| Number of Participants With Self-reported Abstinence | 6-month post quit visit | Participants will self-report whether or not consumed any alcohol in the past 30 days. |
| Average Number of Heavy Drinking Days | 12-month post quit visit | At the 12-month follow-up visit, participants will self-report the number of heavy drinking (\> 5 drinks in day for men, \> 4 drinks in a day for women) days in the past thirty days. |
| Treatment Utilization as Measured by Number of Treatment Visits | 6-month post quit visit | Participants will provide self-report on use of adjunct treatments (e.g., Alcoholics Anonymous, group counseling) for alcohol use during the period between post-treatment and follow-ups. Where available, Department of Veterans Affairs administrative data will be used to determine enrollment or involvement in aftercare treatment. |
| Health Care Related Quality of Life | 12-month post quit visit | Health care related quality of life will be measured by the EuroQol. |
| CBT Treatment Engagement as Measured by the Number of Cognitive Behavioral Therapy Treatment Sessions Completed | Post-treatment, approximately 14 weeks | The number of cognitive behavioral therapy treatment sessions completed by each participant will be measured to determine treatment engagement |
| Incremental Cost-Effectiveness Ratio | 12-month post quit visit | Measure of cost-effectiveness; costs as the numerator and effectiveness as measured by quality-adjusted life years (QALY) as the denominator |
| Number of Participants With Bioverification of Low-risk Drinking | 6-month post quit visit | Participants will provide a fingerstick blood sample. Phosphatidylethanol (PEth) testing will provide any evidence of excessive alcohol use in previous 4 weeks. |
Countries
United States
Participant flow
Pre-assignment details
Eleven participants were deemed eligible to participate in the study but were not randomized. Seven voluntarily withdrew, and four were lost to contact.
Participants by arm
| Arm | Count |
|---|---|
| CBT + mCM + Incentive Participants in this arm will receive 12 sessions of cognitive behavioral treatment, mobile contingency management for alcohol abstinence, and a monetary incentive for 30-day abstinence at the 6-month follow-up.
Cognitive Behavioral Therapy (CBT): Twelve in-person counseling sessions designed to assist participants with becoming abstinent from alcohol use (or reduce use).
Mobile Contingency Management (mCM): Abstinence (measured by breath alcohol) will be intermittently reinforced. For each breath alcohol concentration reading that tests negative, a participant will earn a virtual scratch-off lottery ticket that contains 100 different values.
Long-term incentive: This incentive is $300 for self-reported and bioverified 30-day abstinence from heavy drinking at the follow-up scheduled for 6-months after the initial quit date | 35 |
| CBT + mCM + no Incentive Participants in this arm will receive 12 sessions of cognitive behavioral treatment and mobile contingency management for alcohol abstinence. They will not receive monetary incentive for 30-day abstinence at the 6-month follow-up.
Cognitive Behavioral Therapy (CBT): Twelve in-person counseling sessions designed to assist participants with becoming abstinent from alcohol use (or reduce use).
Mobile Contingency Management (mCM): Abstinence (measured by breath alcohol) will be intermittently reinforced. For each breath alcohol concentration reading that tests negative, a participant will earn a virtual scratch-off lottery ticket that contains 100 different values. | 35 |
| CBT Alone + Incentive Participants in this arm will receive 12 sessions of cognitive behavioral treatment and a monetary incentive for 30-day abstinence at the 6-month follow-up. They will not receive contingency management for alcohol abstinence during the treatment period.
Cognitive Behavioral Therapy (CBT): Twelve in-person counseling sessions designed to assist participants with becoming abstinent from alcohol use (or reduce use).
Long-term incentive: This incentive is $300 for self-reported and bioverified 30-day abstinence from heavy drinking at the follow-up scheduled for 6-months after the initial quit date | 35 |
| CBT Alone + no Incentive Participants in this arm will receive 12 sessions of cognitive behavioral treatment. They will not receive monetary incentive for 30-day abstinence at the 6-month follow-up. They will not receive contingency management for alcohol abstinence during the treatment period.
Cognitive Behavioral Therapy (CBT): Twelve in-person counseling sessions designed to assist participants with becoming abstinent from alcohol use (or reduce use). | 35 |
| Total | 140 |
Baseline characteristics
| Characteristic | Total | CBT + mCM + Incentive | CBT + mCM + no Incentive | CBT Alone + Incentive | CBT Alone + no Incentive |
|---|---|---|---|---|---|
| Age, Continuous | 49 years STANDARD_DEVIATION 13 | 48 years STANDARD_DEVIATION 12 | 49 years STANDARD_DEVIATION 14 | 50 years STANDARD_DEVIATION 15 | 50 years STANDARD_DEVIATION 12 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 8 Participants | 3 Participants | 0 Participants | 3 Participants | 2 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 132 Participants | 32 Participants | 35 Participants | 32 Participants | 33 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 3 Participants | 0 Participants | 1 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 65 Participants | 17 Participants | 12 Participants | 21 Participants | 15 Participants |
| Race (NIH/OMB) More than one race | 3 Participants | 0 Participants | 0 Participants | 1 Participants | 2 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 69 Participants | 18 Participants | 22 Participants | 12 Participants | 17 Participants |
| Region of Enrollment United States | 140 Participants | 35 Participants | 35 Participants | 35 Participants | 35 Participants |
| Sex/Gender, Customized Sex Female | 27 Participants | 6 Participants | 7 Participants | 7 Participants | 7 Participants |
| Sex/Gender, Customized Sex Male | 112 Participants | 29 Participants | 27 Participants | 28 Participants | 28 Participants |
| Sex/Gender, Customized Sex Unknown, not reported | 1 Participants | 0 Participants | 1 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 35 | 0 / 35 | 0 / 35 | 0 / 35 |
| other Total, other adverse events | 2 / 35 | 4 / 35 | 3 / 35 | 1 / 35 |
| serious Total, serious adverse events | 0 / 35 | 0 / 35 | 0 / 35 | 0 / 35 |
Outcome results
Primary
Average Number of Heavy Drinking Days
At the 6-month follow-up visit, participants will self-report the number of heavy drinking (\> 5 drinks in day for men, \> 4 drinks in a day for women) days they have had in the past thirty days.
Time frame: 6-month post quit visit
Population: Sixteen participants were excluded from analyses because they were withdrawn or lost to contact prior to the 6-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Heavy Drinking Days | 15.1 days | Standard Deviation 12.2 |
| CBT + mCM + no Incentive | Average Number of Heavy Drinking Days | 15.9 days | Standard Deviation 10 |
| CBT Alone + Incentive | Average Number of Heavy Drinking Days | 13.2 days | Standard Deviation 11.2 |
| CBT Alone + no Incentive | Average Number of Heavy Drinking Days | 11.3 days | Standard Deviation 11.2 |
Secondary
Average Number of Binge Drinking Days
Participants will self-report the number of binge drinking (heavy drinking within a 2-hour period) days in the past thirty days.
Time frame: 12-month post quit visit
Population: Thirty-two participants were excluded from analyses because they were withdrawn or lost to contact prior to the 12-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Binge Drinking Days | 0.5 days | Standard Deviation 1.5 |
| CBT + mCM + no Incentive | Average Number of Binge Drinking Days | 0.7 days | Standard Deviation 2.8 |
| CBT Alone + Incentive | Average Number of Binge Drinking Days | 0.8 days | Standard Deviation 3.4 |
| CBT Alone + no Incentive | Average Number of Binge Drinking Days | 4.0 days | Standard Deviation 10.5 |
Secondary
Average Number of Binge Drinking Days
Participants will self-report the number of binge drinking (heavy drinking within a 2-hour period) days in the past thirty days.
Time frame: 6-month post quit visit
Population: Sixteen participants were excluded from analyses because they were withdrawn or lost to contact prior to the 6-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Binge Drinking Days | 0.9 days | Standard Deviation 4.8 |
| CBT + mCM + no Incentive | Average Number of Binge Drinking Days | 3.4 days | Standard Deviation 7.6 |
| CBT Alone + Incentive | Average Number of Binge Drinking Days | 1.8 days | Standard Deviation 6.5 |
| CBT Alone + no Incentive | Average Number of Binge Drinking Days | 2.2 days | Standard Deviation 6.7 |
Secondary
Average Number of Drinking Days
Participants will self-report the number of drinking days in the past thirty days.
Time frame: 6-month post quit visit
Population: Sixteen participants were excluded from analyses because they were withdrawn or lost to contact prior to the 6-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Drinking Days | 11.0 days | Standard Deviation 10.2 |
| CBT + mCM + no Incentive | Average Number of Drinking Days | 12.2 days | Standard Deviation 11.6 |
| CBT Alone + Incentive | Average Number of Drinking Days | 7.9 days | Standard Deviation 9.3 |
| CBT Alone + no Incentive | Average Number of Drinking Days | 9.6 days | Standard Deviation 10.7 |
Secondary
Average Number of Drinking Days
Participants will self-report the number of drinking days in the past thirty days.
Time frame: 12-month post quit visit
Population: Thirty-two participants were excluded from analyses because they were withdrawn or lost to contact prior to the 12-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Drinking Days | 10.5 days | Standard Deviation 10.4 |
| CBT + mCM + no Incentive | Average Number of Drinking Days | 8.0 days | Standard Deviation 9.8 |
| CBT Alone + Incentive | Average Number of Drinking Days | 8.1 days | Standard Deviation 9.9 |
| CBT Alone + no Incentive | Average Number of Drinking Days | 12.3 days | Standard Deviation 11 |
Secondary
Average Number of Drinks Per Drinking Day
Participants will self-report the number of drinks on drinking days in the past 30 days.
Time frame: 12-month post quit visit
Population: Thirty-two participants were excluded from analyses because they were withdrawn or lost to contact prior to the 12-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Drinks Per Drinking Day | 3.5 drinks | Standard Deviation 3.7 |
| CBT + mCM + no Incentive | Average Number of Drinks Per Drinking Day | 2.3 drinks | Standard Deviation 2.5 |
| CBT Alone + Incentive | Average Number of Drinks Per Drinking Day | 3.2 drinks | Standard Deviation 2.8 |
| CBT Alone + no Incentive | Average Number of Drinks Per Drinking Day | 2.8 drinks | Standard Deviation 2 |
Secondary
Average Number of Drinks Per Drinking Day
Participants will self-report the number of drinks on drinking days in the past 30 days.
Time frame: 6-month post quit visit
Population: Sixteen participants were excluded from analyses because they were withdrawn or lost to contact prior to the 6-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Drinks Per Drinking Day | 3.4 drinks | Standard Deviation 3.8 |
| CBT + mCM + no Incentive | Average Number of Drinks Per Drinking Day | 3.2 drinks | Standard Deviation 3.3 |
| CBT Alone + Incentive | Average Number of Drinks Per Drinking Day | 2.5 drinks | Standard Deviation 2 |
| CBT Alone + no Incentive | Average Number of Drinks Per Drinking Day | 2.0 drinks | Standard Deviation 2.1 |
Secondary
Average Number of Heavy Drinking Days
At the 12-month follow-up visit, participants will self-report the number of heavy drinking (\> 5 drinks in day for men, \> 4 drinks in a day for women) days in the past thirty days.
Time frame: 12-month post quit visit
Population: Thirty-two participants were excluded from analyses because they were withdrawn or lost to contact prior to the 12-month follow-up visit.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Average Number of Heavy Drinking Days | 2.8 days | Standard Deviation 7 |
| CBT + mCM + no Incentive | Average Number of Heavy Drinking Days | 1.2 days | Standard Deviation 3.1 |
| CBT Alone + Incentive | Average Number of Heavy Drinking Days | 2.4 days | Standard Deviation 6.5 |
| CBT Alone + no Incentive | Average Number of Heavy Drinking Days | 4.5 days | Standard Deviation 10.4 |
Secondary
CBT Treatment Engagement as Measured by the Number of Cognitive Behavioral Therapy Treatment Sessions Completed
The number of cognitive behavioral therapy treatment sessions completed by each participant will be measured to determine treatment engagement
Time frame: Post-treatment, approximately 14 weeks
Population: Two participants were withdrawn from analyses due to missing data.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | CBT Treatment Engagement as Measured by the Number of Cognitive Behavioral Therapy Treatment Sessions Completed | 10.4 CBT sessions | Standard Deviation 2.9 |
| CBT + mCM + no Incentive | CBT Treatment Engagement as Measured by the Number of Cognitive Behavioral Therapy Treatment Sessions Completed | 9.6 CBT sessions | Standard Deviation 3.3 |
| CBT Alone + Incentive | CBT Treatment Engagement as Measured by the Number of Cognitive Behavioral Therapy Treatment Sessions Completed | 9.1 CBT sessions | Standard Deviation 3.8 |
| CBT Alone + no Incentive | CBT Treatment Engagement as Measured by the Number of Cognitive Behavioral Therapy Treatment Sessions Completed | 9.3 CBT sessions | Standard Deviation 3.9 |
Secondary
Health Care Related Quality of Life
Health care related quality of life will be measured by the EuroQol.
Time frame: 12-month post quit visit
Secondary
Incremental Cost-Effectiveness Ratio
Measure of cost-effectiveness; costs as the numerator and effectiveness as measured by quality-adjusted life years (QALY) as the denominator
Time frame: 12-month post quit visit
Secondary
Number of Participants With Bioverification of Low-risk Drinking
Participants will provide a fingerstick blood sample. Phosphatidylethanol (PEth) testing will provide any evidence of excessive alcohol use in previous 4 weeks.
Time frame: 12-month post quit visit
Population: Thirty-two participants were excluded from analyses because they were withdrawn or lost to contact prior to the 12-month follow-up visit. Additionally, 4 participants failed to send in their PEth test kits for analysis.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| CBT + mCM + Incentive | Number of Participants With Bioverification of Low-risk Drinking | 4 Participants |
| CBT + mCM + no Incentive | Number of Participants With Bioverification of Low-risk Drinking | 13 Participants |
| CBT Alone + Incentive | Number of Participants With Bioverification of Low-risk Drinking | 9 Participants |
| CBT Alone + no Incentive | Number of Participants With Bioverification of Low-risk Drinking | 6 Participants |
Secondary
Number of Participants With Bioverification of Low-risk Drinking
Participants will provide a fingerstick blood sample. Phosphatidylethanol (PEth) testing will provide any evidence of excessive alcohol use in previous 4 weeks.
Time frame: 6-month post quit visit
Population: Sixteen participants were excluded from analyses because they were withdrawn or lost to contact prior to the 6-month follow-up visit. Additionally, 7 participants failed to send in their PEth test kits for analysis.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| CBT + mCM + Incentive | Number of Participants With Bioverification of Low-risk Drinking | 13 Participants |
| CBT + mCM + no Incentive | Number of Participants With Bioverification of Low-risk Drinking | 7 Participants |
| CBT Alone + Incentive | Number of Participants With Bioverification of Low-risk Drinking | 13 Participants |
| CBT Alone + no Incentive | Number of Participants With Bioverification of Low-risk Drinking | 9 Participants |
Secondary
Number of Participants With Self-reported Abstinence
Participants will self-report whether or not consumed any alcohol in the past 30 days.
Time frame: 12-month post quit visit
Population: Thirty-two participants were excluded from analyses because they were withdrawn or lost to contact prior to the 12-month follow-up visit.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| CBT + mCM + Incentive | Number of Participants With Self-reported Abstinence | 5 Participants |
| CBT + mCM + no Incentive | Number of Participants With Self-reported Abstinence | 8 Participants |
| CBT Alone + Incentive | Number of Participants With Self-reported Abstinence | 5 Participants |
| CBT Alone + no Incentive | Number of Participants With Self-reported Abstinence | 3 Participants |
Secondary
Number of Participants With Self-reported Abstinence
Participants will self-report whether or not consumed any alcohol in the past 30 days.
Time frame: 6-month post quit visit
Population: Sixteen participants were excluded from analyses because they were withdrawn or lost to contact prior to the 6-month follow-up visit
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| CBT + mCM + Incentive | Number of Participants With Self-reported Abstinence | 5 Participants |
| CBT + mCM + no Incentive | Number of Participants With Self-reported Abstinence | 6 Participants |
| CBT Alone + Incentive | Number of Participants With Self-reported Abstinence | 10 Participants |
| CBT Alone + no Incentive | Number of Participants With Self-reported Abstinence | 5 Participants |
Secondary
Treatment Utilization as Measured by Number of Treatment Visits
Participants will provide self-report on use of adjunct treatments (e.g., Alcoholics Anonymous, group counseling) for alcohol use during the period between post-treatment and follow-ups. Where available, Department of Veterans Affairs administrative data will be used to determine enrollment or involvement in aftercare treatment.
Time frame: 6-month post quit visit
Population: 29 participants were withdrawn from analyses due to missing data.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 0.03 treatment visits | Standard Deviation 0.2 |
| CBT + mCM + no Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 1.5 treatment visits | Standard Deviation 4.5 |
| CBT Alone + Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 2.1 treatment visits | Standard Deviation 5.2 |
| CBT Alone + no Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 0.2 treatment visits | Standard Deviation 0.7 |
Secondary
Treatment Utilization as Measured by Number of Treatment Visits
Participants will provide self-report on use of adjunct treatments (e.g., Alcoholics Anonymous, group counseling) for alcohol use during the period between post-treatment and follow-ups. Where available, Department of Veterans Affairs administrative data will be used to determine enrollment or involvement in aftercare treatment.
Time frame: 12-month post quit visit
Population: 31 participants were withdrawn from analyses due to missing data.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| CBT + mCM + Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 0.6 treatment visits | Standard Deviation 1.6 |
| CBT + mCM + no Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 8.2 treatment visits | Standard Deviation 29.5 |
| CBT Alone + Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 2.9 treatment visits | Standard Deviation 8.9 |
| CBT Alone + no Incentive | Treatment Utilization as Measured by Number of Treatment Visits | 0.3 treatment visits | Standard Deviation 1 |