Baclofen as Add-On to Standard Treatment of Alcohol- Dependent Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Baclofen as Add-On to Standard Treatment of Alcohol- Dependent Patients (NCT01002105), a randomized phase 4 study. The primary outcome is Percent Abstinent Days.

2. Clinical Question

The clinical question is about the reported abstinent-day outcome after adding baclofen or placebo to the same psychosocial program. The primary endpoint combines assessment approaches described in the record: patient self-evaluation, a family member interview, and calculation of cumulative abstinence duration. The endpoint was calculated for each arm as a whole. The posted results therefore describe groups, not individual-level response patterns. They do not indicate how many participants contributed data to the 52-week outcome beyond the group sizes associated with the posted values. The trial also lists secondary outcomes concerning drinking-related obsessive-compulsive symptoms, general health, self-efficacy, social support, and quality of life, but the registry record does not post their results.

3. Trial Design

The registry describes a randomized, double-blind, placebo-controlled trial of baclofen added to a low-intensity psychosocial intervention program. The baclofen arm is described as receiving 50 mg/day over 12 weeks; the placebo arm received placebo alongside the psychosocial program. Follow-up observations are described at 26 weeks and 52 weeks. The primary outcome is percent abstinent days at 52 weeks.

The registry identifies the study as phase 4 and lists enrollment of 75. The posted primary-outcome values are associated with 13 participants in the baclofen arm and 11 in the placebo arm. These group sizes accompany the outcome values; the record does not explain how they relate to enrollment, follow-up, or the number of participants with complete data. It would therefore be inappropriate to infer the reasons for the difference between enrollment and the group sizes reported with the endpoint.

There is a record-level inconsistency in how the design is classified: the allocation is listed as randomized, but the model is listed as single group. At the same time, two arm-level outcome values are posted, one for baclofen and one for placebo. The narrative description identifies a randomized comparison, so the record contains both a two-group description and a single-group model label. The registry does not explain this mismatch.

The study is marked completed. Its sponsor is Sha'ar Menashe Mental Health Center. The registry record does not report the method used to generate the random sequence, conceal allocation, or implement blinding. Nor does it report a protocol-level statistical analysis plan or sample-size justification. Those details should not be inferred from the brief design description.

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

Reasons for not completing this period:

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 Percent Abstinent Days, measured over one year.

The primary endpoint is percent abstinent days at 52 weeks. It expresses abstinent days as a share of the days considered during the assessment period. In general, a percentage-based abstinence outcome can describe the frequency of abstinence over time rather than reducing a participant’s drinking experience to a single point-in-time assessment. It can therefore provide a summary of abstinence across the period relevant to the endpoint.

The registry describes three assessment components: patient self-evaluation, a family member interview, and calculation of cumulative abstinence duration, defined as the total number of days of abstinence. It says the number of abstinent days was calculated for each arm as a whole. The record does not specify how these sources were combined, how disagreements were resolved, or how missing assessments affected the calculation.

The posted arm-level values are 40.0 for baclofen and 36.0 for placebo. No dispersion measure, confidence interval, or statistical test is reported with these values. As a result, the record gives a descriptive comparison but not a direct estimate of its precision. In general, a confidence interval indicates the range of values reasonably compatible with the data and the statistical method used. Without one, readers cannot use the registry results alone to judge how uncertain the arm-level estimates are.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, double-blind, placebo-controlled trial and gives arm-level primary results. It does not report a detailed statistical analysis plan, the statistical model used for the primary endpoint, or an inferential comparison. The explanations below distinguish what the record reports from general statistical principles.

What does an arm-level value tell us?

The primary endpoint is percent abstinent days at 52 weeks, and the registry gives one value for each group. An arm-level value condenses outcome information into a group summary. In general, such a summary is useful for describing the recorded result, but it does not show the spread of outcomes among participants. Two groups can have the same average or percentage while having different distributions of individual outcomes. Without a measure of variability, readers cannot see how much outcomes differed within each group.

The record says that abstinent days were calculated for each arm as a whole, using patient self-evaluation, a family member interview, and cumulative abstinence duration. It does not explain the calculation procedure in enough detail to reconstruct it. It does not state how each information source contributed to the result, how conflicting reports were handled, or how missing assessments were treated. The posted values should therefore be understood as registry-reported summaries, not as independently reproducible calculations.

Why does uncertainty matter?

In general, an estimate based on a sample has uncertainty because another sample from the same population could yield a different estimate. A confidence interval expresses that uncertainty under a specified statistical method and its assumptions. It helps readers assess both the range of effects compatible with the data and the precision of the estimate. The registry record does not report a confidence interval or another uncertainty measure for either arm or for the comparison.

A statistical test addresses a related but different question: how compatible are the observed data with a specified null hypothesis, given the test’s assumptions? A p-value is not an estimate of treatment effect and is not the probability that a hypothesis is true. No p-value or test result for the primary comparison is reported in the registry. Therefore, the posted values cannot be characterized as statistically significant or not statistically significant on the basis of this record.

What can randomization and blinding contribute?

In general, random assignment helps make treatment groups comparable with respect to measured and unmeasured characteristics, on average, when the randomization process is properly implemented. Double blinding is intended to limit the influence of treatment expectations on care and outcome assessment. These principles can strengthen a comparison, but labels alone do not show how procedures were carried out. The registry does not report the sequence-generation method, allocation concealment, who was blinded, or whether blinding was assessed. It also does not report adherence or exposure information. Those omissions limit what can be concluded about implementation from the registry record.

The record has a design-classification mismatch: it lists randomized allocation and a single-group model, while also describing baclofen and placebo arms and posting values for both. This makes the registry’s structured design description less internally consistent than its narrative trial description. The record does not explain the mismatch. The randomized, placebo-controlled description remains part of the registry, but the discrepancy should be kept in view when interpreting how the study is represented.

What are the planning illustrations?

In general, a sample-size calculation asks how many participants a future study might need to detect a chosen effect under stated assumptions. It is a planning exercise, not a description of the observed trial’s power after results are known. The registry’s stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect for such an illustration is defined as a stated fraction of the observed effect. The record specifies that non-time-to-event illustrations are expressed as participants per arm. These assumptions describe the planning illustration, not necessarily the design decisions used for this completed trial.

When the effect used for planning comes from an observed trial estimate, the illustration inherits uncertainty in that estimate. In general, a smaller assumed effect requires a larger sample size to detect under otherwise similar assumptions. This is a statistical principle, not a claim about the result of this trial. Planning illustrations should not be interpreted as observed power, proof that the trial was adequately powered, or evidence about the outcome itself. The registry does not report the trial’s own sample-size justification, so its design rationale cannot be inferred from planning calculations.

What is not reported?

The registry record does not report the primary comparison’s model, confidence interval, standard error, p-value, adjustment strategy, or analysis population. It does not provide a detailed missing-data method or explain whether the endpoint was analyzed according to randomized assignment. It also does not describe interim analyses, and no interim-analysis plan should be inferred. Without these details, the posted summaries cannot be expanded into a more complete estimate of treatment effect or its uncertainty.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists five secondary outcomes: Obsessive-Compulsive Drinking Scale Scores, General Health Questionnaire, General Self-Efficacy Scale, Multidimensional Scale of Perceived Social Support, and the Quality of Life Enjoyment and Satisfaction Questionnaire. Although the record lists six outcome measures, it does not post results for the secondary outcomes. It does not report a multiplicity-adjustment method, a hierarchy among outcomes, or which outcomes were treated as confirmatory. In general, assessing multiple outcomes can increase the chance of finding at least one apparently notable result by chance if each is tested separately. Whether and how that issue was handled is not reported in the registry record.

The record lists zero analyses. It therefore does not provide a posted analysis set from which to assess a protocol-defined primary analysis, secondary comparisons, or adjusted estimates. The methods for handling missing outcome data are not reported. The registry does not explain whether missing observations were excluded, imputed, or addressed through another method. It also does not state how participants with incomplete follow-up were treated in the primary analysis.

Although the study is described as randomized, the registry does not specify whether the reported results follow randomized assignment or another analysis population. The meaning of the group sizes associated with the primary outcome is also not explained. In general, analysis-population definitions matter because they determine which participants contribute to an estimate and how departures from the assigned treatment are handled. Those details are not reported in the registry record, so the posted values cannot be confidently assigned to a particular analysis population.

11. 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 0% reporting threshold.

The registry reports zero serious adverse events among 32 participants at risk in the baclofen group and zero among 32 participants at risk in the placebo group. It also reports zero other adverse events among 32 participants at risk in each group. These are counts as recorded, not estimates of comparative risk. No deaths are reported in the record.

A zero count in a registry entry does not establish that an event is impossible or that there is no safety risk. In general, event counts are interpreted in light of the number of participants observed, the duration and completeness of surveillance, and the definitions used for events. The registry record does not describe the adverse-event collection procedures, event definitions, or the relationship between the safety groups and the groups contributing to the primary outcome. It also does not provide uncertainty estimates or a statistical comparison for the safety figures.

The safety values should therefore be read narrowly: the posted record lists zero serious adverse events and zero other adverse events in the stated at-risk group counts. It does not support broader conclusions about safety beyond what was recorded.

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

The posted primary result describes percent abstinent days at 52 weeks as 40.0 for baclofen and 36.0 for placebo. It shows the two arm-level values reported in the registry. Since the record provides no uncertainty interval or test of the comparison, the values do not establish how precise the comparison is or how compatible it is with chance variation under a specified model. Nor should the values be converted into a claim of statistical significance or lack of significance.

The trial description says participants were randomized and double-blinded, with baclofen or placebo added to a low-intensity psychosocial intervention program. This design is relevant to the intended comparison, but the registry does not report details of randomization, concealment, or blinding procedures. It also does not report adherence, missing-data handling, or the analysis population. Those limits make it important to distinguish the trial’s design description from the evidence contained in its posted result.

The endpoint captures a group-level summary of abstinent days, assessed using patient self-evaluation, family member interview, and cumulative abstinence duration. The registry does not explain how those sources were combined or how incomplete information was handled. The values do not reveal individual variation or whether a particular participant experienced a specific pattern of abstinence. They also do not summarize the secondary outcomes, for which results are not posted.

In general, a result’s interpretation depends on the estimate, its uncertainty, the analysis used, and the completeness of outcome reporting. Here, the record provides descriptive primary values but leaves those other elements largely unspecified. The figures therefore do not establish a treatment effect with known precision, and they should not be used as a stand-alone basis for clinical decisions. They are a limited account of what the registry reports for this trial’s primary endpoint.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between a result and a complete comparison. A randomized, double-blind design is described, and the registry posts an arm-level primary endpoint for each group. Yet the record does not give an uncertainty interval or an inferential test. Without these, readers can identify the reported values but cannot judge the precision of the comparison using the registry results alone.

The endpoint also illustrates how measurement construction matters. Percent abstinent days is described as drawing on patient self-evaluation, a family member interview, and cumulative abstinence duration. The record does not explain how these sources were brought together. In general, clarity about measurement and data handling is necessary for reproducibility and for understanding what a summary represents.

Several reporting features warrant attention: the record lists enrollment of 75, while the primary outcome values are associated with group sizes of 13 and 11; a single-group model label appears alongside a randomized two-arm narrative; and secondary outcomes are listed without posted results. These details do not resolve the findings, but they show why design labels, outcome denominators, analysis populations, and complete reporting should be considered together.

The record also makes a useful distinction between planning illustrations and trial results. In general, calculations based on an observed effect can inform planning for later studies, but they do not describe observed power or replace a trial’s original sample-size rationale. The registry does not report that rationale. Thus the statistical value of the posted record lies in what it documents and, equally, in identifying the information needed for a fuller evaluation.

14. 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 primary endpoint is reported only as arm-level values, without a confidence interval, standard error, dispersion measure, or statistical test. This limits assessment of precision and does not permit a registry-based conclusion about statistical significance. The record does not report the statistical model, adjustment strategy, or analysis population for the primary outcome.

The primary outcome description names three assessment components but does not explain how patient self-evaluation, family member interview, and cumulative abstinence duration were combined. The method for dealing with disagreement, incomplete reports, or missing follow-up is not reported. The record also does not clarify the meaning of the group sizes attached to the posted endpoint, or how they relate to the stated enrollment.

There is a mismatch between the randomized allocation and the single-group model label, despite the narrative description of a placebo-controlled comparison and the presence of two arm-level results. The registry does not explain this discrepancy. The randomization method, allocation concealment, blinding procedures, adherence, and treatment exposure are also not described.

Secondary outcomes are listed, but their results are not posted. The record does not describe multiplicity control or a prespecified hierarchy of outcomes. It does not report the trial’s sample-size justification or interim-analysis procedures. The safety record gives event counts but does not describe ascertainment procedures or provide a comparative statistical analysis. These limitations apply to interpretation of the registry record; they do not establish that the underlying study did not collect or analyze these data.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Baclofen as Add-On to Standard Treatment of Alcohol- Dependent Patients — NCT01002105.
• Registry record last updated 2017-01-27; status last verified 2016-11.
• Results first posted 2017-01-27.
• 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.

18. Record Summary

The registry describes a completed phase 4, randomized, double-blind, placebo-controlled trial of baclofen added to a low-intensity psychosocial intervention program for alcohol-dependent patients. Baclofen is described as 50 mg/day over 12 weeks, with follow-up observations at 26 weeks and 52 weeks.

The primary endpoint is percent abstinent days at 52 weeks. The posted arm-level values are 40.0 for baclofen, associated with 13 participants, and 36.0 for placebo, associated with 11 participants. The registry does not report uncertainty estimates or a statistical test for this comparison. It lists secondary outcomes but does not post their results. Missing-data methods, the analysis population, and a detailed statistical plan are not reported in the registry record.