Study of Acamprosate to Prevent Alcohol Relapse in Criminal Justice Supervisees: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of Acamprosate to Prevent Alcohol Relapse in Criminal Justice Supervisees (NCT00249379), a randomized phase 4 study. The primary outcome is Drinking and Other Drug Use.

2. Clinical Question

3. Trial Design

This was a Phase 4 randomized, parallel-group study with no masking. The registry lists Virginia Commonwealth University as the sponsor, enrollment of 26, and study status as terminated. The recorded start is 2005-06 and primary completion is 2008-08. These design details establish the study’s registered structure, but do not by themselves show how consistently participants received their assigned care or how outcomes were collected.

The acamprosate arm received the drug. The no-medication arm received Building Social Networks counseling and did not receive acamprosate. The registry does not state that counseling was or was not given in the acamprosate arm, so the intervention contrast should not be described as medication versus identical counseling without medication. The allocation ratio and details of sequence generation are not reported in the registry record.

Although enrollment was 26, the primary outcome population was smaller. The registry says that only 13 acamprosate participants were analyzed, because one participant was lost to follow-up after receiving an initial medication supply. It also says no primary outcome data were collected for the control arm because funding ran out. The safety record lists 14 participants at risk in the acamprosate group and 12 in the control group; those denominators describe the posted safety figures and should not be substituted for the primary outcome analysis population.

The registry lists two secondary outcomes: retention in drug court and recidivism rates. It does not report their results in the registry record. The reason the study was terminated, beyond the statement that funding ran out for control-arm primary outcome collection, is not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Only 13 Acamprosate participants were analyzed because one participant was lost to follow-up after being given an initial supply of medication for the study. No data were collected for the Control Arm because funding ran out for the study.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Drinking and Other Drug Use, measured over 12 weeks.

The primary outcome is the number of participants using alcohol and other drugs during 12 weeks. It is a participant-count outcome: each participant is counted according to whether they meet the outcome definition during the stated period. The registry describes the endpoint but does not provide additional operational detail about how use was assessed, whether alcohol and other drug use were combined into one rule, or how repeated use was handled. Those details are not reported in the registry record.

A count of participants with an event can be useful because it gives a direct account of how many people experienced the defined outcome in the observed group. In a randomized comparison with outcome data from both arms, the corresponding group counts could be used to assess the difference in event frequency, with uncertainty described using an appropriate comparative estimate and confidence interval. General statistical explanation: a confidence interval describes the range of effect values reasonably compatible with the data and the method used; it is not a guarantee that the true effect lies within that range.

In this study, the posted primary outcome records 6 participants in the acamprosate arm among the 13 analyzed. The control outcome is not available, so the endpoint supports a description of the observed acamprosate group only. It does not support an estimate of the randomized between-arm contrast. The endpoint’s clinical relevance depends on the outcome definition and assessment process, details of which are not fully reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is registered as randomized and parallel, with no masking. In a randomized parallel design, participants are assigned to one of the study groups and generally remain in that group for the comparison. Randomization is intended to make groups comparable on average, including on characteristics that were not measured. That rationale depends on having outcomes available for both groups and does not remove the need to examine missing data, adherence, and the actual analysis population.

What does the primary count represent?

The endpoint is a count of participants using alcohol and other drugs during 12 weeks. The registry classifies the result as a binary outcome expressed as participants with an event. General explanation: a binary outcome records whether each participant does or does not meet a defined event criterion. A group count can then describe how many participants met that criterion. The count alone does not show how the event was defined in detail, how often it occurred, or whether alcohol and other drug use were counted separately. The registry record does not report those operational details.

The posted acamprosate result is 6 participants among 13 analyzed. No corresponding control outcome was collected. A comparative analysis would require outcome information from both arms. Without it, a difference in event proportions, relative effect, confidence interval, or significance test cannot be estimated from these posted primary results. General explanation: a confidence interval communicates uncertainty around an estimate; a statistical test evaluates the data against a specified null hypothesis. Neither can repair a missing comparison group outcome.

Why are the analyses not comparative?

The registry indicates that values were missing or not estimable for a two-arm binary endpoint. This is consistent with the absence of control-arm primary outcome data. It is important to distinguish an unavailable estimate from an estimate near no effect: no comparative value is reported, rather than a measured result showing no difference. No primary outcome analysis results are listed in the registry record.

The record reports no analyses among the outcome measures. It does not report the statistical analysis plan, the planned effect measure, adjustment variables, model specification, or any interim analyses. These details should not be inferred from the randomized design or from general conventions. In particular, no claim can be made about whether the investigators planned an intention-to-treat analysis or a per-protocol analysis.

How should planning illustrations be read?

General explanation: sample-size planning estimates the number of participants that might be needed to detect a chosen effect under specified assumptions. It is not a measure of how much power the completed study actually had. The registered planning assumptions describe a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power or evidence that a planned comparison was completed. Since the control primary outcome is absent, a comparative observed effect is not available from the posted primary results for interpretation.

For a binary endpoint, the precision of a group estimate depends on the number of participants and the event frequency. General explanation: fewer observations usually yield less precise estimates, and sparse event counts can make some statistical approximations unreliable. Here, the reported group count and analysis size are limited, and the missing control outcome prevents evaluation of a between-group estimate altogether. No confidence interval or p-value for the primary comparison is reported.

What is and is not established by the design?

Randomization describes how participants were assigned, but the registry entries do not provide enough information to assess sequence generation, concealment, adherence, or completeness of outcome ascertainment. No masking was used, which means the study was open-label as registered; the registry does not describe whether outcome assessors were separately masked. These design details matter when interpreting a study, but missing details should be treated as unreported rather than filled in by assumption.

The registry lists retention in drug court and recidivism rates as secondary outcomes. It does not report their findings. It also does not report multiplicity procedures, missing-data methods, or a prespecified hierarchy for outcomes. General explanation: when several outcomes or analyses are examined, multiplicity can increase the chance of at least one apparently notable result unless the analysis strategy accounts for it. That concern cannot be assessed from a list of outcomes alone. In this record, the primary limitation is more fundamental: there is no control-arm primary outcome for the randomized comparison.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Acamprosate")
n      <- c(13)
events <- c(6)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Acamprosate  13  6  46.2  19.2  74.9  23.2  70.9  23.0  71.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome, Drinking and Other Drug Use, and two secondary outcomes: retention in drug court and recidivism rates. It also reports four outcome measures. The results described in the registry record do not include findings for the two listed secondary outcomes. Whether additional outcomes were planned, how outcomes were prioritized, and whether any multiplicity adjustment was prespecified are not reported in the registry record.

General explanation: testing or estimating several outcomes can create multiplicity concerns, because the more questions examined, the more opportunities there may be for an apparently noteworthy result by chance. A prespecified hierarchy or adjustment can help manage that concern. No such approach is reported, so it cannot be evaluated. In any event, the absence of control-arm primary outcome data prevents the principal randomized comparison regardless of multiplicity handling.

Missingness affects the primary outcome in two ways. One acamprosate participant was lost to follow-up after receiving an initial supply of study medication, leaving 13 analyzed in that arm. For the control arm, the registry says no primary outcome data were collected because funding ran out. The record does not report any imputation, sensitivity analysis, or other method for handling these unavailable outcomes. It also does not report whether the analyzed acamprosate participants were selected according to a prespecified analysis population.

The safety record has different denominators: 14 at risk in the acamprosate group and 12 in the control group. These figures do not resolve the missing primary endpoint and should not be treated as the primary analysis population. The reason for loss to follow-up beyond the information recorded, the outcomes of those with missing data, and the intended handling of missingness are not reported in the registry record.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The safety record lists zero serious adverse events among 14 participants at risk in the acamprosate group and zero among 12 participants at risk in the control group. These are the posted counts for the serious-event category. The registry does not list serious adverse event terms. Death counts are not reported in the registry record.

The record also lists zero other adverse events among 14 participants at risk in the acamprosate group and zero among 12 in the control group. These safety figures are separate from the primary outcome, and their denominators differ from the 13 acamprosate participants analyzed for that outcome. They should be interpreted as recorded counts within the listed safety groups, not as a complete account of every possible safety outcome.

General explanation: observing zero events does not establish that the underlying risk is zero. It means that no events of that recorded category were reported among the participants counted during the available safety observation. The registry record does not provide details about event collection, follow-up duration for safety, or statistical comparisons. The zero counts therefore do not establish equal safety between groups or rule out uncommon events.

13. What the Result Does, and Does Not, Mean

The posted primary outcome gives a descriptive result for the analyzed acamprosate group: 6 participants met the recorded outcome during the 12-week period among 13 analyzed. It does not show how that group compares with no medication, because the registry reports no primary outcome data for the control arm. The reason recorded for this absence is that funding ran out for the study.

Consequently, the result cannot be read as an estimate of a treatment effect. It does not establish that acamprosate changed alcohol or other drug use, nor does it establish that there was no change. The primary outcome comparison is unavailable rather than negative or null. No between-arm effect estimate, confidence interval, or test result is reported for the primary outcome.

The study’s randomized design is relevant because it identifies the intended comparative framework. But randomization alone cannot supply the missing control outcomes. Nor does the single-arm count indicate what might have happened in the control group over the same period. A comparison based on the posted primary results would require data that are not in the registry record.

The safety record reports zero serious adverse events in each listed group, using the stated denominators, and also records zero other adverse events. Those observations describe the recorded events in the safety groups; they do not show that the groups had identical risk or that no harm is possible. Death information is not reported. Secondary outcomes are named but their results are not reported in the registry record.

The record therefore offers limited descriptive information: one arm’s primary endpoint count and the available safety counts. It leaves the main comparative question unanswered. This distinction between no observed comparative result and evidence of no effect is central to interpreting the study responsibly.

14. Why This Trial Matters Statistically

This trial matters statistically because its registered design and its available outcome data do not align sufficiently to support the main randomized comparison. A randomized study is intended to compare outcomes between groups. The control arm’s primary outcome was not collected, so the posted primary result describes only the analyzed acamprosate group. The distinction is a basic but important one: a within-group observation is not a between-group treatment estimate.

The record also illustrates why analysis populations and denominators need to be stated alongside results. The primary analysis includes 13 acamprosate participants, while the safety record lists 14 at risk in that arm and 12 in the control arm. These figures answer different descriptive questions. Treating them as interchangeable could misstate which participants contributed to which outcome.

Missing data are not all the same. The registry identifies one participant lost to follow-up after an initial medication supply and separately reports that no control primary outcome data were collected because funding ran out. Those circumstances have different scope and implications. A complete analysis would require transparent reporting of how missingness was handled, but such methods are not reported in the registry record.

Finally, the safety counts show why zero events should be described precisely rather than interpreted as proof of no risk. The posted counts are useful as recorded observations, but the registry does not provide the detail needed for broader safety comparisons. The record is therefore a useful case for separating design, observed data, and inferential conclusions: the randomized design is registered, the primary comparison is unavailable, and the available counts should be kept within their stated limits.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most consequential limitation is the absence of control-arm primary outcome data. The registry says that no data were collected for that arm because funding ran out. As a result, the primary outcome cannot support a randomized comparison, and no comparative effect estimate or uncertainty interval is reported.

The acamprosate primary analysis includes 13 participants. The registry explains that one participant was lost to follow-up after receiving an initial medication supply. It does not report a missing-data method, sensitivity analysis, or the outcome status of that participant. The number analyzed is also distinct from the safety denominator of 14 at risk in the acamprosate group.

The record does not provide detailed endpoint ascertainment procedures, the operational definition of alcohol and other drug use, medication dose or schedule, adherence information, or analysis-plan details. Allocation concealment and sequence-generation procedures are also not reported in the registry record. These gaps limit evaluation of how the registered design was implemented and how the primary outcome was measured.

The registry lists two secondary outcomes but does not report their results in the registry record. It does not report a multiplicity approach, interim analyses, or the statistical methods used for outcome analysis. The stated planning assumptions do not substitute for an analysis plan or a completed comparative analysis.

Finally, the study is marked terminated, but the registry does not state the full reason for termination. Funding running out is specifically linked to the lack of control-arm primary outcome data; it should not be generalized into an explanation for every study decision. The safety record contains zero events in the listed categories, but event-collection and safety-follow-up details are not reported.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study of Acamprosate to Prevent Alcohol Relapse in Criminal Justice Supervisees — NCT00249379.
• Registry record last updated 2016-05-11; status last verified 2016-04.
• Results first posted 2016-05-11.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT00249379 is a Phase 4 randomized, unmasked, parallel-group study sponsored by Virginia Commonwealth University. It enrolled 26 participants and is listed as terminated. The recorded start is 2005-06, and primary completion is 2008-08. The study concerned acamprosate use among alcohol-dependent criminal justice supervisees.

The primary outcome was the number of participants using alcohol and other drugs during 12 weeks. The registry reports 6 participants among 13 analyzed in the acamprosate arm. One participant was lost to follow-up after receiving an initial medication supply, and no control-arm primary outcome data were collected because funding ran out. The primary randomized comparison is therefore unavailable.

Retention in drug court and recidivism rates are listed as secondary outcomes, but their results are not reported in the registry record. Safety counts list zero serious and zero other adverse events in both groups; deaths are not reported. The available results support a description of the recorded outcomes, not a comparative conclusion.