Methods

Study design: RCT, single blind.

Recruitment modality of participants: individuals seeking treatment at the outpatient treatment unit of the APT Foundation, or respondents to newspaper advertisements or public service announcements.

Participants

Number of participants: 122 (41 in 2 arms selected for this review).

Gender: 27% female.

Age: mean age 30.8 years (SD 5.5 years).

Condition: "All subjects met current DSM‐III‐R criteria for cocaine dependence, and for concurrent alcohol dependence (85%) or alcohol abuse (15%)".

Other relevant information:

TSF arm:

Baseline substance use:

• mean weekly cocaine use 5.4 ± 8.6;

• days cocaine use/past 30 12.7 ± 8.0;

• cocaine use g/week/past 30 days 4.6 ± 6.6;

• mean drinks per drinking day/past 30 days 10.2 ± 5.7;

• days of alcohol use/past 30 days 12.3 ± 8.0;

• years of cocaine use ‐ lifetime 7.5 ± 3.9;

• years of alcohol misuse ‐ lifetime 7.1 ± 6.3;

• life‐time psychiatric disorders: any affective disorder 24%, any anxiety disorder 24%, ASP 42%, any non‐ASP 35%;

• ASI composite scores: medical 0.15 ± 0.26, employment 0.71 ± 0.28, legal 0.09 ± 0.18, family/social 0.21 ± 0.15, psychological 0.26 ± 0.17, alcohol 0.30 ± 0.19, cocaine 0.58 ± 0.24, other drugs 0.06 ± 0.06;

• race: white 40%, African‐American 56%, Hispanic 0%, other 4%;

• married/cohabiting 42%;

• unemployed 76%;

• education: less than high school 40%;

• primary route of administration: nasal 20%, smoking 72%, intravenous 8%;

• previous treatment: alcohol 36%, drugs 72%.

CBT arm:

Baseline substance use:

• mean weekly cocaine use (mean ± SD) 5.6 ± 6.2;

• days cocaine use/past 30 days; 15.6 ± 6.5;

• cocaine use g/week/past 30 days 5.0 ± 5.1;

• mean drinks per drinking day/past 30 days 10.6 ± 8.0;

• days of alcohol use/past 30 days 18.5 ± 7.6;

• years of cocaine use ‐ lifetime 5.8 ± 3.1;

• years of alcohol misuse ‐ lifetime 7.3 ± 6.4;

• life‐time psychiatric disorders: any affective disorder 33%, any anxiety disorder 6%, ASP 46%, any non‐ASP 50%;

• ASI composite scores: medical 0.19 ± 0.29, employment 0.67 ± 0.32, legal 0.09 ± 0.17, family/social 0.12 ± 0.15, psychological 0.16 ± 0.19, alcohol 0.40 ± 0.20, cocaine 0.58 ± 0.18, other drugs 0.07 ± 0.05;

• race: white 32%, African‐American 63%, Hispanic 1%, other 0%;

• married/cohabiting 32%;

• unemployed 53%;

• education: less than high school 32%;

• primary route of administration: nasal 11%, smoking 84%, intravenous 5%;

• previous treatment: alcohol 32%, drugs 58%.

Interventions

Description of the experimental and control interventions

The trial included 5 treatment arms: CBT plus disulphiram; TSF plus disulphiram; CM plus disulphiram; CBT plus no medication; TSF plus no medication. We considered only the latter 2 psychosocial therapy arms. CBT was based on Marlatt's relapse prevention model and TSF was adapted from that used in Project MATCH and was grounded in the concept of substance dependence as a spiritual and medical disease.

Route of delivery: treatments were manual‐guided; 4 doctoral‐level psychologists conducted CBT; 2 masters‐level clinicians conducted TSF.

Number of participants allocated to each group: 25 in CBT plus no medication; 19 in TSF plus no medication.

Duration of the intervention: 12 weeks, 16 individual sessions.

Duration of follow up: 12 weekly assessments within‐treatment, and at 1, 3, 6, 12 months.

Country of origin, setting: a non‐profit substance abuse treatment centre (APT Foundation) affiliated with Yale University in New Haven, Connecticut, USA.

Outcomes

1.1.1 Alcohol abstinence as maximum number of weeks of consecutive alcohol abstinence during treatment

1.1.2 Illicit drug abstinence as maximum number of weeks of consecutive abstinence from cocaine during treatment

1.2.1 Alcohol abstinence as number achieving 3 or more weeks of consecutive alcohol abstinence during treatment

1.2.2 Illicit drug abstinence as number achieving 3 or more weeks of consecutive abstinence from cocaine during treatment

1.2.3 Alcohol abstinence during follow‐up year

1.2.4 Illicit drug abstinence as abstinence from cocaine during follow‐up year

Notes

All sessions were recorded and checked and rated for accuracy and fidelity of the intervention.

"Subjects also met weekly with an independent clinical evaluator who collected urine specimens, assessed cocaine and alcohol use and monitored other clinical symptoms".

"Patients were paid $25 for each follow‐up interview, with a $10 increase for each consecutive interview they attended, to encourage more complete data collection. In addition, patients were paid a $5 bonus for attending an interview within 28 days of the target interview date".

• Only 39 subjects completed the full 12‐week treatment (compliant treatment completers)

• Participants in the pharmacological arms stayed longer in treatment (participants were not blind to their intervention)

• The specific type of self‐report questionnaires was not reported in the primary paper (1998), only in the follow‐up paper

• Results are reported as number of weeks of continuous abstinence

• The follow‐up report (2000) does not provide any endpoint scores (only results of the random‐effects regression model)

• Use of cocaine and alcohol were strongly associated with each other during treatment, particularly for the subjects assigned to disulphiram

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Not enough information provided; e.g. "Of the 122 randomised subjects, 117 initiated the treatment".

Allocation concealment (selection bias)

Unclear risk

Not stated.

Blinding of outcome assessment (detection bias)
Objective outcomes

Unclear risk

Not available.

Objective measures used rather as an accuracy check than an outcome (urine specimens and breathalyser tests conducted by a blinded evaluator).

Blinding of outcome assessment (detection bias)
Subjective outcomes

Low risk

Within‐study assessments:
"independent clinical evaluator who collected urine specimens, assessed cocaine and alcohol use; the evaluator saw patients in an office physically separated from the therapy offices and instructed patients not to disclose detail of their therapist or treatment".
Follow‐up assessments (2000 paper):
"Patients were assessed at face‐to‐face follow‐up interviews conducted 1, 3, 6 and 12 months after the 12‐week termination point by an independent clinical evaluator who was blind to both psychotherapy and pharmacotherapy condition".

Incomplete outcome data (attrition bias)
End of Study outcomes

High risk

Within‐treatment assessments (1998):

"Assignment to disulphiram was associated with significantly better retention in treatment".

The psychotherapy groups had significantly lower retention rates than the medication groups:
"subjects assigned to disulphiram treatment were retained significantly longer than those assigned to no medication (8.4 versus 5.8 weeks. F= 8.7, p< 0.05)".

Retention rates:

• CBT/disulphiram group (mean 8.8 weeks);

• CM/disulphiram (8.4 weeks);

• TSF/disulphiram (8.0);

• CBT/no medication (6.3);

• TSF/no medication (5.3).

"However, such analyses, ..., are confounded by differences among the treatments in retention".

Only 30% completed treatment, however:
"Subjects who remained in treatment the full 12 weeks/16 sessions (n=39) did not differ from those who did not start treatment or dropped out (n=83) in terms of gender, race, employment status, route of administration, presence of lifetime affective, anxiety or antisocial personality disorder, but those who met criteria for a nonASP Axis II disorder, were significantly more likely to complete treatment than these who did not (48.1% versus 23.1%)".

Comments:
1) baseline characteristics provided for the ITT sample (n = 122); but
2) rates of consecutive abstinence provided for the exposed sample (n = 117);
3) it is not known whether missing outcome data were balanced in numbers across intervention groups, because group breakdowns for drop‐outs are not provided;
4) psychotherapy groups (CBT, TSF) differed significantly at baseline: for frequency of alcohol use; and medication groups had lower baseline cocaine use.

Incomplete outcome data (attrition bias)
Follow up

High risk

All groups had a comparable number of follow‐up data points. However, number of drop‐outs was not reported for each group separately.

"It is possible that poorer‐functioning subjects who dropped out of treatment early were under‐represented in the follow‐up data, inflating outcomes in all groups".

"Participants who completed more sessions had better outcomes during follow‐up".

• Subjects with higher age of onset of drug use had more follow‐up data

• Subjects with non‐ASP Axis II disorders had more follow‐up data

• No significant differences between those followed up and those not followed up

Percentage of treatment days abstinent from cocaine, percentage of treatment days abstinent from alcohol, percentage of cocaine‐negative urine screens, medication compliance during treatment.

Number of drop‐outs and reasons:

Number randomised: 122 (25 TSF, 19 CBT);

Number initiated: 117 (23 TSF, 18 CBT) ‐ no other reason provided;

Number removed from the trial: 8 (1 did not comply with medication, 1 medication side effects. 4 clinical deterioration, 2 administrative discharge);

Number drop‐outs: 70 (no group breakdowns ‐ no other reasons);

Number completed treatment: 39;

Number followed up at least once: 96, i.e.:

• 1 month: 68;

• 3 months: 67;

• 6 months: 63;

• 12 months: 72.

Methods

Study design: RCT.

Recruitment modality of participants: for 1 year, participation in the study was proposed systematically to each adult outpatient who was treated for opioid or cocaine dependence.

Participants

Number of participants: 110.

Gender: 72.3% male.

Age (mean ± SD): 35 ± 7.8 years.

Condition: problem alcohol use based on questions from the AUDIT questionnaire, i.e. excessive drinking (7 ≤ AUDIT score < 13 for men and 6 ≤ AUDIT score < 13 for women); and alcohol dependence (score > 13); 43.8% were classified as excessive drinkers and 56.2% as alcohol dependents.

Other relevant information: opiate dependence treatment with methadone substitution (56.2%) or diacetyl morphine (heroin treatment; 12%); no opioid substitution and treatment for opiate or cocaine dependence (31.7%).
Most participants with cocaine dependence or with opiate dependence also had tobacco or cannabis dependence. Most participants had 1 or more concomitant psychiatric disorders (mood disorder, 35.6%; personality disorder, 34%; anxiety disorders, 14.7%; psychotic disorders, 9.4%). "Diagnoses were established according to the criteria of the ICD‐10) by a resident and a senior psychiatrist".

Interventions

Description of the experimental and control interventions: the intervention group was BI and the control group was TAU.

(1) BI: BI was delivered in 1 session, based on WHO guidelines, delivered by a trained staff (4 hours' training). The intervention group received the same TAU as controls. The outpatient staff consisted of a psychiatrist, general practitioner, psychologist, nurse, and social worker.

(2) TAU: "The control group received TAU in addition to AUDIT and score feedback. TAU refers to outpatient pharmacological and psychosocial treatment. Maintenance treatment with methadone or heroin included medical and psychiatric follow‐up, primary health care, psychosocial interventions, and administration of opiate treatments in a clinical setting. Psychosocial treatment included medical and psychiatric follow‐up, primary health care, psychosocial interventions, and, if necessary, administration of pharmacotherapy in a clinical setting".

Number of participants allocated to each group: 60 in BI, 52 in TAU.

Duration of the intervention (mean ± SD): 16 ± 4.7 minutes.

Duration of follow up: 3 and 9 months.

Country of origin, setting: specialised outpatient clinic in the Division of Substance Abuse of the University Hospitals of Geneva, Switzerland.

Outcomes

2.1.1 Alcohol use as AUDIT scores at 3 months

2.1.2 Alcohol use as AUDIT scores at 9 months

2.1.3 Alcohol use as number of drinks per week at 3 months (number of glasses of alcohol per week, 1 glass: 10 g of alcohol; wine = 100 mL; beer = 250 mL; spirits = 25 mL)

2.1.4 Alcohol use as number of drinks per week at 9 months

2.2.1 Alcohol use as decreased alcohol use at 3 months

2.2.2 Alcohol use as decreased alcohol use at 9 months

2.2.3 and 2.2.4 Increased or unchanged alcohol use at 3 and 9 months (i.e. reverse of the above)

Notes

The participants in both groups were already in treatment for opioid or cocaine dependence before study inclusion. Participants allocated to BI received this intervention 2 or 3 weeks after AUDIT screening.

The WHO Manual recommends the referral of individuals with alcohol dependence to specialist treatment without providing BI.

All screened participants received feedback that explained the meaning of their AUDIT score.

Almost 40% of the sample was lost to follow up.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "The randomisation scheme was drawn by a statistician, who used the Web site [http://www.randomizer.org/]. A random permuted block method was used, with blocks of 4 patients".

Allocation concealment (selection bias)

Low risk

Quote: "The sequence was concealed from all investigators with numbered opaque sealed envelopes prepared by the statistician and handed over to the physician in charge of the study".

Blinding of outcome assessment (detection bias)
Objective outcomes

Unclear risk

Not available, objective measures not used.

Blinding of outcome assessment (detection bias)
Subjective outcomes

High risk

Not stated.

Unpublished information: "There is no blinding assessment".

Incomplete outcome data (attrition bias)
End of Study outcomes

Unclear risk

Not available. The study did not assess outcomes at the time of the study end.

Incomplete outcome data (attrition bias)
Follow up

Low risk

Modified ITT analysis (multiple imputation, random assumption).
At T0 ‐ 1 person not included in analysis because of data‐entry errors, both in both control and intervention group.

Number of drop‐outs and reasons:

"Of the BI group, 59.3% completed the last observation and of the control group, 58.8% completed it"

• Intervention (T0 = 51, T3 = 29, T9 = 30);

• Control (T0 = 59, T3 = 30, T9 = 35).

No reasons provided for drop‐outs, but regression showed no differences:
"Logistic regressions showed that the ‐ Type of drinker ‐ and ‐ Treatment group ‐ did not explain the missingness of data".
"Hence, these variables displayed no particular pattern, meaning that the data for excessive drinkers and for alcohol‐dependent patients, as well as for the control group and the intervention group, were equally likely to be missing".

Comment: dichotomous outcomes: 40% of participants dropped out, but the observed event risk was 10% to 20% (control), and 60% to 80% (intervention).

Methods

Study design: RCT open label, 3 arms.

Recruitment modality of participants: flyers displayed in 5 methadone treatment sites.

Participants

Number of participants: 256.

Gender: 59.2% male.

Age (mean ± SD): 51.2 ± 8.4 years.

Condition: reported moderate‐to‐heavy alcohol use based on questions from the ASI. Methadone maintenance treatment was an inclusion criterion (minimum 3 months).

Other relevant information: fair/poor health: 60.4%.
Depressive symptoms: 80.8%.
Poor emotional well‐being: 67.5%.

Ethnicity: African‐American: 45.1%; white: 18.8, Latino: 26.7, Other: 9.4. Education: high school graduate 58%.
Partnered: 54.3%.
Employed: 17.3%.
Recent alcohol use at baseline (Mean number standard drinks last 30 days): 0‐40: 25.1; 41‐89: 24.7; 90‐180: 26.7; 180+: 23.5.
Marijuana use in past 30 days: 16%.
IDU in past 30 days: 40%.
Smoke > 1 pack/day: 56.1%.
Self‐help programme in past 30 days: 21.2%.

Social support: primarily from drug users 12.6%; primarily non‐drug users 48.6%, both: 34.9%.

Interventions

Description of the experimental and control interventions: (1) nurse‐led HHP group sessions; (2) MI delivered in group sessions (MI‐group), and (3) MI delivered in 1‐on‐1 sessions (MI‐single).

(1) HHP: didactic style, also interactive as the group raised questions. Delivered by a nurse and hepatitis‐trained research assistant. Sessions based on "The comprehensive health seeking and coping paradigm (CHSCP; Nyamathi 1989), originally adapted from Lazarus and Folkman's (1984) stress and coping paradigm and Schlotfeldt's (1981) health seeking paradigm". Staff trained on the integration of the CHSCP into their education delivery.

Focus: progression of HCV infection and the culturally sensitive strategies that infected individuals can adopt to prevent or reduce accumulated damage to liver functioning. Strategies included: discussing the dangers of alcohol use on hepatitis (cognitive factors), discussing ways to avoid alcohol and other drugs, eating a balanced diet, dangers of reinfection of HCV by IDU, receiving unsafe tattoos and piercing, having unprotected sexual behaviour, and being consistent in engaging in other health‐related behaviours. Additional health promoting activities: enhancing coping, such as seeking positive social support, getting
support from religion and building self‐esteem in individuals with a history of drug and alcohol addiction. The HHP was directed by a detailed protocol.

(2) MI‐group: focus: alcohol, risky behaviours, MI spirit; by trained MI specialists, i.e. a PhD‐prepared psychologist conducted primarily the MI‐group sessions. Content of the individual and group sessions was identical, guided by a detailed protocol and biweekly meetings with the investigator and therapists. The average number of participants was 6 (range 5 to 7).

(3) MI‐single: focus: alcohol, risky behaviours, MI spirit; a MSW‐prepared researcher conducted primarily the individual MI sessions.

Number of participants allocated to each group: HHP: N = 87; MI group: N = 79; MI single: N = 90.

Duration of the intervention: 3 x 60‐minute sessions, spaced 2 weeks apart.

Duration of follow‐up: 6 months.

Country of origin, setting: 5 methadone treatment sites in Los Angeles and Santa Monica, USA.

Outcomes

3.1.1 Alcohol use (unpublished) as number of standard drinks consumed per day over the last 30 days

3.1.2 Illicit drug use (unpublished) as frequency of drug use (as measured by ASI drug)

3.1.3 Illicit drug use (unpublished) as a composite drug score (frequency*severity for all drugs taken)

3.2.1 Alcohol use as > 50% reduction in number of standard drinks consumed per day over the last 30 days

3.2.2 Alcohol abstinence as abstinence from alcohol over the last 30 days

Outcomes 4.1.1 to 4.2.2 refer to the individual (single) format of MI.

Notes

6 participants reported no alcohol use at baseline.

A total of 86.7% of participants completed all 3 sessions and 91.3% completed the 6‐month follow up.

The sessions were open; i.e. participants who had not completed their 3 sessions with their original cohort could complete with a later cohort.

The original protocol describes HHP as a control intervention (UCG).

Means (SD) of outcomes measures (ASI, TLFB) are not provided for any of the outcomes; baseline scores are also not provided.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "This study was a randomised controlled trial"

Unpublished information: "As participants were enrolled, they were systematically assigned to each of the three arms. In terms of randomisation, we used random assignment using a random number table".

Allocation concealment (selection bias)

High risk

Masking: open label.
Source of information: published protocol of the trial.

Blinding of outcome assessment (detection bias)
Objective outcomes

Unclear risk

Not available, objective measures not used.

Blinding of outcome assessment (detection bias)
Subjective outcomes

High risk

Masking: open label.
Source of information: published protocol of the trial.

Incomplete outcome data (attrition bias)
End of Study outcomes

Unclear risk

Not available. The study did not assess outcomes at the time of the study end.

Incomplete outcome data (attrition bias)
Follow up

Low risk

Comment:
All analyses were ITT; however, it is not stated which method of data imputation was used for ITT analysis.
Missing data balanced across groups.
Comparability of all 3 arms assessed at baseline.

Number of drop‐outs and reasons:

• MI‐S (90), 86% completed all sessions, 9% lost to follow up;

• MI‐G (79), 85% completed all sessions, 10% lost to follow up;

• HHP (87), 89% completed all sessions, 7% lost to follow up.

Unpublished information: "The 6 reported abstainers were distributed as follows: 2 in MI‐Single, 3 in MI‐Group and 1 in HHP.
No one was excluded from the final regression model based on ethnicity. The statement was erroneously carried over from preliminary modelling. However, since ethnicity was not important in that modelling, it was not included in the final model and there was no need to exclude anyone based on ethnicity.
The 6 abstainers were excluded from the logistic regression analysis. "A missing value for drug‐using partners caused an additional case to be omitted (actually there were 248 cases in the regression model rather than 249. Two subjects had missing values for drug‐using partners)".

Methods

Study design: RCT.

Recruitment modality of participants: study was advertised at 3 NEP sites using posters and NEP volunteers offered all clients referral cards. NEP clients called a study telephone to be screened by a research assistant at a separate research site in hospital. During the initial study visit, all NEP clients presented their study cards (received at NEP). Between February 1998 and October 1999.

Participants

Number of participants: 187.

Gender: 119 male (63.6%).

Age: mean 36.2 years.

Condition: problem alcohol use, i.e. AUDIT‐positive (> 8) active IDUs. "Current alcohol abuse or dependence diagnosis was ascertained using the SCID interview. 159 (85.0%) met DSM‐IV criteria for current alcohol abuse or dependence (80% for abuse, 70% for dependence)".

Other relevant information:

• mean education: 11.5 years;

• ethnicity: 162 (86.6%) Caucasian;

• most frequently injected drug: heroin for 141 (75.4%) subjects, cocaine for 15 (8.0%), heroin and cocaine for 31 (16.6%);

• 120 (64.1%) participants visited the NEP at least once a month;

• mean AUDIT score at screening was 22.2;

• 159 (85.0%) met DSM‐IV criteria for current alcohol abuse or dependence (80% for abuse, 70% for dependence);

• mean ± SD number of drinking days in the past 30 days prior to baseline assessment: 12.0 ± 10.3;

• 71.4% of quantities on all drinking days exceeded conventional criteria defining heavy alcohol consumption (5+ drinks for men and 3+ drinks for women);

• mean ± SD drinks per drinking days 7.3 ± 5.8.

Interventions

Description of the experimental and control interventions: (1) brief MI and (2) control group.

(1) MI: focus on alcohol use and HIV risk‐taking

Goals: to assess the degree to which the participant engages in hazardous drinking; to identify relationships between alcohol consumption and alcohol‐related negative consequences including HIV risk behaviour; to identify goals for behaviour change and any barriers to change.

• Included a written change plan, designed to reduce the link between alcohol consumption and hazardous behaviours that may lead to negative consequences of drinking, including HIV risk behaviour

• Interventionist trained by studying the manual and watching MI tapes from Project MATCH

• Standard delivery of the MI protocol

• Adherence monitoring by: an MI checklist completed by the therapist after each session and audiotapes of sessions were randomly reviewed by a supervisor trained in MI

(2) Control: assessment‐only, approximately 3 hours

Number of participants allocated to each group: 95 in MI, 92 in control group.

Duration of the intervention: 2 therapist sessions, 1 month apart; 1st session: 60 minutes, 2nd session: 30 to 45 minutes.

Duration of follow‐up: 1 and 6 months.

Country of origin, setting: NEP clients, study site: Rhode Island Hospital in Providence, USA.

Outcomes

5.1.1 Alcohol use as number of days in the past 30 days with alcohol use at 1 month

5.1.2 Alcohol use as number of days in the past 30 days with alcohol use at 6 months

5.2.1 Alcohol use as 25% reduction of drinking days in the past 30 days

5.2.2 Alcohol use as 50% reduction of drinking days in the past 30 days

5.2.3 Alcohol use as 75% reduction of drinking days in the past 30 days

5.2.4 Alcohol use as 1 or more drinking days' reduction in the past 30 days

5.2.5 Alcohol use as 7 or more drinking days' reduction in the past 30 days

Secondary outcome: number of days in the past 30 days with IRRB ‐ defined as answer to 1 question: have you used needles etc. after someone else? (reported only for a subset of 109 participants in the 2002b paper).

Notes

Study retention: 96.8% at 6 months.

Control and MI subjects received identical research assessments at baseline, 1 and 6 months:

• at baseline and 1 month later, both MI and control group received a list of referrals for substance abuse and medical treatment;

• participants in the control group spent approximately 3 total hours (assessment time) with research staff, "the assessment included sections on demographics, drug and alcohol use, drug and alcohol treatment, health‐related quality of life, attitudes and experiences with alcohol and HIV risk behavior";

• the assessment control group also experienced meaningful reduction in alcohol use;

• 6‐month follow up: 11 subjects were interviewed in prison and 6 were interviewed by telephone;

• total reimbursement: $90 with $20 given at baseline, $30 at the 1‐month interview and $40 at the final interview;

• 65 (34.8%) participants reported 4 or fewer drinking days at baseline: their maximum possible decrease in drinking days at follow‐up is 4 or less (i.e. floor and ceiling effects);

• change in heroin use was not associated with change in alcohol use;

• the association between change in IRRB days and change in alcohol use days was not statistically significant.

The paper reporting IRRB outcomes (Stein 2002b) was included in another Cochrane review (Meader 2010), therefore it was not considered for this review.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Not enough information provided: "Following the baseline interview subjects were assigned to treatment conditions using a randomisation schedule created with permuted blocks of eight assignments." "After randomisation, the research interventionist saw participants assigned to MI...".

Allocation concealment (selection bias)

Unclear risk

Not stated how the randomisation schedule was prepared: "This method ensured that the treatment groups were balanced in number to within four patients throughout the trial. The data manager prepared the randomisation schedule before the first patient enrolled".

Blinding of outcome assessment (detection bias)
Objective outcomes

Unclear risk

Not available. Objective measures used rather as an accuracy check than an outcome:

"During the initial study visit, all NEP subjects presented their study cards (received at NEP), underwent blood alcohol level testing (to ensure subjects were not inebriated, BAL < 0.04)".

Blinding of outcome assessment (detection bias)
Subjective outcomes

Low risk

"At each follow‐up assessment, research assistants were blinded to the treatment condition of the subject; the interventionist did not perform research assessments".

Incomplete outcome data (attrition bias)
End of Study outcomes

Unclear risk

Not available. The study did not assess outcomes at the time of the study end.

Incomplete outcome data (attrition bias)
Follow up

Low risk

"We conducted an intent‐to‐treat analysis using a conservative 'worst case scenario' strategy in which observations with missing follow‐up data were assigned the maximum value of 30 drinking days, a data imputation approach which tends to minimize observed reductions in mean drinking days across time.

To ensure that our substantive results were not sensitive to missing observations (there were no condition differences in missing data) we replicated our analyses using observations with complete data (n = 181), and using other imputation strategies (e.g. mean substitution, regression estimation and 'best case scenario'). All imputation strategies resulted in substantively consistent findings.

To evaluate the adequacy of random assignment, we used t‐ and x2‐tests to compare treatment groups with respect to background characteristics and baseline measures of drinking behaviours and alcohol problems".

Number of drop‐outs and reasons:
There were no study withdrawals: 93 of 95 in the MI group received both MI sessions: 2 people missed their second session. 6‐month follow‐up data were available for 96.8% (n = 181) of the 187 randomly assigned subjects. 3 subjects in each treatment arm were lost to follow‐up at 6 months.