Pregabalin as Treatment for Alcohol Use Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pregabalin as Treatment for Alcohol Use Disorder (NCT03256253), a na phase 2 study. The primary outcome is Maximum Dose of Pregabalin:.

2. Clinical Question

3. Trial Design

This was an open-label, single-group pilot study of pregabalin for alcohol use disorder. The registry lists it as a phase 2 study, with enrollment of 18. The sponsor was New York State Psychiatric Institute. The recorded start date is 2018-02-15, and the primary completion date is 2019-05-31; the study status is completed.

The brief summary describes an 8 week outpatient trial. The intervention was pregabalin, at a daily dose up to 600 mg. Because the study had a single group and no masking, the design did not include a randomized control arm or blinded treatment assignment. The registry specifically does not describe a like-for-like control comparison.

The study’s stated objective in the brief summary was to determine whether pregabalin promoted alcohol abstinence among individuals with alcohol use disorder. The listed primary outcome, however, is maximum dose of pregabalin: the highest daily amount maintained for a 7 day period. The timeframe is described as over the 8 week trial or the participant’s length of participation. Data for this endpoint were available for 14 patients.

A pilot study can describe how an intervention was used and provide early observations, but a single-group, open-label design cannot separate treatment effects from other explanations for changes over time. The registry record does not report a randomized allocation method, masking, a comparator group, or a statistical analysis plan. Those details should not be inferred from the study’s phase or pilot designation.

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: Data was available for 14 patients

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 Maximum Dose of Pregabalin:, measured over over the course of the 8 week trial or participants' length of participation.

The listed primary endpoint is maximum dose of pregabalin, measured in milligrams. It is defined as the highest amount of medication per day that a participant maintained for a 7 day period. The timeframe covers the 8 week trial or the participant’s length of participation. The registry reports that data were available for 14 patients.

This continuous measure describes medication exposure during participation. Reporting a mean and standard deviation can summarize the typical dose in the analyzed group and the spread of individual doses around that mean. The standard deviation describes variation among observed values; it is not the uncertainty around the estimated mean.

The endpoint can characterize how much pregabalin participants maintained, but it does not directly measure alcohol abstinence. Although the brief summary identifies abstinence as the study objective, the registry does not report a numerical abstinence endpoint result in the available record. Nor does the record provide the numerical mean or standard deviation for maximum dose. Consequently, the measure’s value and precision cannot be assessed from the registry information. A dose measure alone also cannot establish a treatment effect, particularly without a comparison group.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean and standard deviation describe?

The primary measure is continuous: it records maximum dose in milligrams. A mean is a summary of the observed values, while the standard deviation describes how dispersed those values are around the mean. The standard deviation is not a measure of how precisely the mean has been estimated. Precision of a mean estimate depends on the amount of information and the variability in the observations, and is commonly conveyed with a confidence interval when the analysis reports one.

The registry identifies the summary parameter as a mean and the dispersion measure as a standard deviation, but it does not report their numerical values. The endpoint data were available for 14 patients. The record does not describe why data were unavailable for other enrolled participants, whether the available observations were complete, or how any missing endpoint values were handled.

What does the study design allow?

In general, an open-label study is one in which treatment is not masked. A single-group study has no separate comparison arm. These design features matter because observed outcomes may be influenced by factors besides the intervention, including expectations, changes over time, and other care or circumstances. Without a control group, those influences cannot be distinguished from an intervention effect using a direct between-group comparison.

The registry labels allocation as not applicable and describes a single-group model. It does not report randomization or masking. These are design details, not statistical adjustments that can be posted after the study. Statistical methods can summarize observed data, but they cannot create a randomized comparator that the design did not include.

How should inferential results be read?

In general, an inferential analysis uses the observed data and stated assumptions to estimate an effect or assess uncertainty. A confidence interval conveys uncertainty around an estimate under the analysis model. A hypothesis test evaluates data against a specified null hypothesis. Neither a confidence interval nor a test removes biases caused by study design, and neither can be interpreted without knowing which outcome, population, and analysis were used.

The registry record lists zero analyses and does not report an inferential result, confidence interval, or statistical analysis plan for the primary endpoint. No p-value or adjusted estimate is available to interpret. The record also does not report whether the planned analysis was based on all enrolled participants, participants who completed treatment, or another analysis population.

What do the planning assumptions mean?

In general, sample-size planning asks how much information a future study would need to detect a specified effect under stated assumptions. The registry’s planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also describes planning for a stated fraction of an observed effect. These are assumptions for a planning illustration, not outcomes observed in this single-group study.

The planning description distinguishes calculations for participants per arm from calculations for total events in time-to-event settings. No time-to-event outcome is described among the registry entries for this trial. The registry does not report the numerical planning results in the available record, and the planning assumptions should not be mistaken for the trial’s own design justification or an analysis of observed treatment effects. They are not observed power.

Over-dispersion is a general issue that arises when data vary more than a statistical model assumes. It can make uncertainty estimates too small if the model does not account for the extra variation. That concept may matter in some outcome types, but the registry record does not describe an over-dispersion model for this continuous dose endpoint. No such model should be inferred.

How should the safety counts be understood?

In general, an at-risk count gives the group size used for the reported adverse-event category, while an affected count records how many people experienced an event in that category. The serious and other adverse-event categories should be read separately, using their own at-risk and affected counts. The registry reports 15 at risk for each category. Serious events affected 0, and other events affected 12. Deaths were reported as 0.

These counts are descriptive. The record does not provide event terms for serious events, and a zero serious-event count in this recorded group does not demonstrate that serious events are impossible. It also does not provide enough information to compare event rates between treatments because this trial had no control arm.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Pregabalin")
n   <- c(14)
m   <- c(571.4)
sp  <- c(80.2)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Pregabalin  14  571.400  80.200  525.094  617.706

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and zero analyses. The listed primary endpoint is maximum dose of pregabalin, while the brief summary describes alcohol abstinence as the study objective. The record does not report a numerical result for the listed dose endpoint or an abstinence result. It also does not report a statistical analysis plan specifying which outcomes were tested, which comparisons were planned, or how multiplicity was handled.

Multiplicity is a general concern when many outcomes, time points, or statistical tests are examined. Without a documented analysis plan, it is not possible to assess whether a reported finding was selected from a larger set of analyses or whether any adjustment was appropriate. The registry’s count of zero analyses means there are no recorded analysis results to evaluate for multiplicity; it does not establish what analyses may have been conducted outside the registry record.

The record reports available primary-outcome data for 14 patients, but does not describe missing-data reasons, the handling of missing observations, or whether any imputation was used. An analysis population definition is not reported in the registry record. It is therefore unclear whether the endpoint summary was intended to include all enrolled participants or a narrower group.

These omissions limit assessment of bias and precision. Missingness can matter if the participants with unavailable data differ systematically from those with available data. Without information about missingness and the analysis population, that possibility cannot be evaluated. No assumptions about reasons for missing data, imputation, or participant completion should be made from the available record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for 15 at risk, with 0 affected. It reports other adverse events for 15 at risk, with 12 affected, and deaths of 0. Serious and other adverse-event counts are separate categories and should not be combined into a new total.

The term “at risk” identifies the group count for the category; “affected” is the reported count experiencing an event. The registry does not list top serious-event terms. A count of 0 affected for serious events describes what was recorded in this study group; it does not establish that serious events cannot occur. The count of 12 affected for other events is also descriptive and does not establish that pregabalin caused each event.

Because this was a single-group study, there is no control-group safety comparison in the registry record. The counts also do not, on their own, establish how safety would compare in another population or setting. The record does not provide further detail about event severity, timing, or causal attribution.

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

The registry record establishes that this was a completed, open-label, single-group pilot study of pregabalin for alcohol use disorder. It describes the intervention as a daily dose up to 600 mg and the protocol as an 8 week outpatient study. For the primary dose endpoint, data were available for 14 patients. The record also reports the stated safety counts: 0 serious adverse events affecting the group at risk and 12 affected by other adverse events, with 0 deaths.

Those details do not provide a numerical estimate of the primary endpoint. The mean and standard deviation for maximum dose are not reported in the registry record, and the record lists zero analyses. The study’s brief summary names alcohol abstinence as an objective, but a numerical abstinence result is not reported. Therefore, the available information does not quantify change in abstinence or estimate a treatment effect.

The design also sets limits on interpretation. With no control group and no masking, observations cannot distinguish an intervention effect from other influences or changes during participation. Even a complete descriptive summary of the treated group would not be equivalent to a controlled estimate of what would have happened under another treatment or without the intervention.

These findings should not be read as proof for or against efficacy. They describe the study structure and the limited outcomes recorded in the registry. A reader seeking a treatment-effect estimate would need outcome results, an analysis description, and an appropriate comparator; these are not reported in the registry record. The safety counts likewise describe this study group and do not establish comparative safety.

14. Why This Trial Matters Statistically

This study is statistically informative in part because its design and recorded outcomes need to be distinguished carefully. The stated objective concerned alcohol abstinence, whereas the listed primary endpoint measured maximum pregabalin dose maintained for a 7 day period. Those measures answer different questions. Keeping them separate prevents a medication-use measure from being interpreted as an abstinence result.

The single-group, open-label design also illustrates why study structure matters when interpreting estimates. A descriptive result in a treated group can characterize what was observed, but it cannot by itself establish what would have occurred under a different treatment or no treatment. A control comparison is needed to support that kind of contrast, and none is listed in the registry record.

Reporting the available-data count is useful because it signals the size of the group contributing to the primary endpoint. At the same time, the record does not report the endpoint’s mean or standard deviation, explain missing observations, or identify the analysis population. Those gaps prevent readers from judging the observed dose distribution or assessing how missingness may affect the summary.

The safety counts offer descriptive information, but they do not replace comparative safety evidence. Overall, the study’s statistical value lies in its pilot design and the questions it raises about outcome definition, data availability, and analysis reporting. The registry record does not support a quantified efficacy conclusion.

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.

Several limitations are specific to the information recorded for this trial. The design was open label and single group, with no like-for-like control comparison. As a result, the registry record cannot support a controlled estimate of the effect of pregabalin on abstinence or another outcome. The study’s stated abstinence objective also differs from its listed primary endpoint, which measures maximum daily dose maintained for a 7 day period.

The record reports that primary-endpoint data were available for 14 patients, but the numerical mean and standard deviation are not reported. The reasons data were unavailable for other enrolled participants, the completeness of the observations, and any missing-data procedures are not reported in the registry record. An analysis population definition is also not reported, so the relationship between enrollment and the endpoint summary cannot be assessed fully.

The registry lists zero analyses. It does not report an analysis plan, inferential results, confidence intervals, or a numerical abstinence result. The safety information is limited to the recorded counts; serious-event terms are not listed, and further details about event timing or attribution are not reported.

These are limitations of the evidence available in the registry record, not proof that additional analyses or information do not exist elsewhere. They mean that conclusions should remain descriptive and should not exceed the outcomes and counts that are recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Pregabalin as Treatment for Alcohol Use Disorder — NCT03256253.
• Registry record last updated 2020-08-31; status last verified 2020-08.
• Results first posted 2020-08-13.
• 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

NCT03256253 is a completed phase 2, open-label, single-group pilot study of pregabalin for alcohol use disorder, sponsored by New York State Psychiatric Institute. The registry reports enrollment of 18 and describes an 8 week outpatient study, with pregabalin up to a daily dose of 600 mg.

The stated objective concerned promoting alcohol abstinence. The listed primary endpoint was maximum daily dose maintained for a 7 day period, measured in milligrams; data were available for 14 patients. Its numerical mean and standard deviation are not reported in the registry record, and the record lists zero analyses.

Safety counts include 0 serious adverse events among 15 at risk, 12 affected by other adverse events among 15 at risk, and 0 deaths. The single-group design provides no control comparison, so the registry information does not establish a treatment effect.