This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for The Impact of Oral Ethanol and Vaped Ethanol on the Evaluation of Impairment (NCT04522973), a na na study. The primary outcome is Blood Alcohol Concentration.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04522973 |
| Phase | NA |
| Condition | Electronic Cigarette Use |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Virginia Commonwealth University |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people enrolled in a trial about electronic cigarette use. The registry record lists an enrollment of 12. The primary outcome was blood alcohol concentration, measured as percent alcohol.
Intervention
The study included sessions in which participants used an e-cigarette liquid containing ethanol, with or without an ethanol-containing beverage. The record also lists conditions using an e-cigarette liquid without ethanol, again with or without an ethanol-containing beverage.
Comparator
The four conditions vary whether the beverage and the e-cigarette liquid contain ethanol. The design is described as a within-group four-condition comparison, rather than a randomized comparison between separate arms.
Primary question
The study aimed to assess whether using an ethanol-containing e-cigarette changes blood alcohol concentration compared with using an e-cigarette without ethanol. Its broader stated purpose was to examine whether ethanol-containing e-cigarettes affect breath, blood, or oral-fluid tests, field sobriety tests, or other tests of sobriety.
3. Trial Design
The registry record describes a completed, single-group study sponsored by Virginia Commonwealth University. Its title is The Impact of Oral Ethanol and Vaped Ethanol on the Evaluation of Impairment. The record lists the phase and allocation as NA and masking as none. The study is not described as a randomized comparison between separate groups.
The design is described as a within-group four-condition comparison. Participants completed four sessions, each lasting approximately five hours, with sessions separated by at least 48 hours. The conditions combined a beverage with or without ethanol and e-cigarette liquid with or without ethanol. The listed combinations therefore allow the study to examine oral ethanol and ethanol in e-cigarette liquid in different combinations. The session order followed a Latin-square arrangement, but the order was not recorded because it was not considered relevant to the study outcomes.
The primary outcome was blood alcohol concentration. Blood was collected before drinking and at the listed post-drinking times; e-cigarette use occurred at the listed times after drinking. The record also lists horizontal gaze nystagmus, the walk and turn test, and the one leg stand test as secondary outcomes. It reports 25 outcome measures overall.
The study status is completed. The registry record lists a start date of 2023-04-21 and a primary completion date of 2024-07-18. These design details describe what was planned or recorded, but they do not supply outcome estimates. The record does not report the primary outcome values or the statistical analyses used to compare the conditions.
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
| Stage | Within Group Four Condition Comparison |
|---|---|
| STARTED | 12 |
| COMPLETED | 7 |
| NOT COMPLETED | 5 |
Reasons for not completing this period:
| Reason | Within Group Four Condition Comparison |
|---|---|
| Lost to Follow-up | 4 |
| Could not adhere to study schedule | 1 |
Analysis population for the primary outcome, as defined in the registry: Blood Alcohol Concentration (% alcohol)
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.
| Characteristic | Unit | Within Group Four Condition Comparison |
|---|---|---|
| Participants analysed | 7 | |
| Age, Continuous | years | 24.6 (SD 3.5) |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 5 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 7 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 2 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 |
| Race (NIH/OMB): White | Participants | 3 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 7 |
6. Primary Endpoint
The registry lists the primary outcome as Blood Alcohol Concentration, measured over Blood collected before (baseline) and after (0, 40, 55, 200, 215) drinking. The e-cigarette was used at 50 and 210 minutes post-drinking..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | percent alcohol |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is blood alcohol concentration, measured as percent alcohol. The registry describes measurements at baseline and after drinking, with blood collected at 0, 40, 55, 200, and 215 minutes after drinking. The e-cigarette was used at 50 and 210 minutes after drinking. The stated measurement plan covers six time points over six hours.
Blood alcohol concentration is used to assess whether the measurement changes in relation to use of e-cigarette liquid containing ethanol compared with e-cigarette liquid without ethanol. Measuring blood at several points can describe the course of the concentration over time, rather than relying on a single measurement. The timing also places measurements around the recorded e-cigarette-use times, although the registry record does not report the results at those time points.
The record identifies the outcome as a mean with standard deviation. In general, a mean describes the average measurement in a group or condition, while a standard deviation describes the spread of individual measurements around that average. Neither statistic, by itself, establishes whether an observed difference is precise or whether it is attributable to a particular component of the conditions. The registry record does not report the blood alcohol concentration means, standard deviations, or comparisons.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record sets out a question about whether use of an ethanol-containing e-cigarette affects blood alcohol concentration relative to use of an e-cigarette without ethanol. It also states a broader interest in breath, blood, oral-fluid, field-sobriety, and other sobriety tests. The listed primary endpoint is blood alcohol concentration; the record names horizontal gaze nystagmus, the walk and turn test, and the one leg stand test as secondary outcomes.
Although the study is marked completed, the registry record does not report numerical results for the primary endpoint. It gives no condition-specific means or standard deviations, no estimated differences, and no confidence intervals or p-values. It also reports no analyses. Accordingly, the record does not allow a reader to determine the direction, size, or precision of any blood alcohol concentration difference across conditions. The stated purpose and measurement schedule are not substitutes for observed outcome estimates.
The within-group structure matters for interpretation. Each participant’s sessions were arranged across four combinations of beverage and e-cigarette liquid. This differs from assigning separate groups to separate conditions. A comparison across conditions in such a design may use within-person information, but the registry record does not say how the observations were analyzed, how dependence among repeated measurements was handled, or whether comparisons were adjusted for other factors. Those analysis details are not reported in the registry record.
The record’s description of Latin-square session ordering indicates that order was arranged, but it also says the order was not recorded because it was not relevant to the outcomes. It does not report a test for order effects or explain how possible period or carryover effects were assessed. These considerations cannot be resolved from the design description alone.
The registry record reports 25 outcome measures, yet it does not provide a statistical analysis plan or identify which outcomes were formally tested. Without that information, the role of multiple comparisons and the possibility of selective reporting cannot be evaluated. The absence of posted analyses is not evidence that the conditions were equivalent; it means that the record does not show the estimates needed to assess whether any differences were observed.
The study’s posted serious-adverse-event information is also limited. It lists zero serious adverse events, two other adverse events, and zero deaths in the reported group, with seven at risk for each event category. These safety counts do not provide information about blood alcohol concentration effects, sobriety-test performance, or the comparative statistical results.
In short, the record describes a completed study and its intended comparisons, but does not report results that answer the primary statistical question. Any interpretation about the magnitude or precision of the endpoint differences would require results that are not reported in the registry record.
9. Statistical Methods Explained
The record identifies blood alcohol concentration as a continuous outcome summarized by a mean and standard deviation. It describes a single-group, within-group comparison across four conditions. However, it does not report the model, test, estimates, uncertainty intervals, or analysis population used. The explanations below are general statistical context, not a description of analyses reported for this study.
What does a mean and standard deviation describe?
In general, a mean is the arithmetic average of measured values. A standard deviation describes how much individual observations vary around that average. Reporting both can give a reader a basic picture of the typical measurement and its spread. The mean and standard deviation do not, on their own, quantify the uncertainty in a comparison between conditions. That uncertainty depends on the design, the number and pattern of observations, and the method used to analyze them.
For repeated measurements, observations from the same participant are generally related. A participant’s values across conditions or time points are not necessarily independent of one another. In general, an analysis should reflect that dependence when estimating condition differences and their uncertainty. The registry record does not state whether the analysis used a paired approach, a repeated-measures model, or another method.
Why does the measurement schedule matter?
Blood alcohol concentration was measured before drinking and at multiple post-drinking times. Such a schedule can describe how measurements change over time and how values at one time point relate to values at another. The e-cigarette was used at 50 and 210 minutes post-drinking, while blood collection was listed at 0, 40, 55, 200, and 215 minutes after drinking, in addition to baseline. This timing can make the interpretation sensitive to the specific time point being compared. A single average across time points would answer a different question from condition-specific estimates at each time point.
The record does not explain whether the primary analysis was based on individual time points, a summary across time, or a model of the full time course. It also does not say whether baseline measurements were used for adjustment. Those choices influence what an estimated condition effect represents, so they cannot be inferred from the endpoint description alone.
What would an effect estimate and confidence interval mean?
In general, an effect estimate expresses the size and direction of a difference or association for a defined comparison. A confidence interval conveys the uncertainty around that estimate under the assumptions of the analysis. A narrower interval indicates greater precision than a wider interval, but precision is not the same as clinical importance. An interval that includes values on both sides of no difference may be compatible with more than one interpretation. The registry record does not report an effect estimate or confidence interval for the primary endpoint.
A p-value, in general, describes how unusual data at least as inconsistent with a specified null hypothesis would be under the statistical model, if that model and its assumptions were correct. It does not measure the probability that the null hypothesis is true, nor does it measure the size or importance of an effect. No p-value for the primary endpoint is reported in the registry record, and no formal analysis is listed.
Why does the four-condition structure matter?
The conditions vary both beverage ethanol and e-cigarette-liquid ethanol. In principle, comparisons among the combinations can address different questions: the role of beverage ethanol, the role of ethanol in the e-cigarette liquid, and whether the relationship between those components depends on their combination. An interaction analysis is one general way to examine whether the association with one component differs according to the presence of another component. The registry record does not report whether such comparisons or an interaction analysis were planned or performed.
Because the design is within-group, condition contrasts could account for the fact that the same participants took part in multiple sessions. In general, that can be useful because comparisons can incorporate within-person variation. It also requires attention to repeated observations, session order, and the assumptions of the chosen analysis. The Latin-square ordering is described, but no method for handling order, period, or carryover effects is reported.
What do the planning illustrations represent?
The registry record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. These are planning calculations, not results from an analysis of the trial. Any sample sizes derived from them are planning illustrations, not observed power. The record does not report the trial’s own sample-size justification, and the study’s four-condition, within-group design should not be mistaken for the separate-arm assumptions used in those illustrations.
The posted record does not provide the observed effect on which those planning illustrations would depend, nor does it report the calculated sample-size values in the information available for interpretation. The illustrations therefore cannot establish whether the trial was adequately powered for its actual design or outcomes. Power calculations also do not replace reporting estimated effects and their uncertainty.
Finally, statistical assumptions matter. In general, over-dispersion occurs when the observed variability exceeds what a model assumes. If present and unaccounted for, it can make uncertainty estimates too small. The registry record does not report a statistical model or diagnostics, so it is not possible to assess whether this or other assumptions were examined.
10. Multiplicity, Missing Data and Analysis Populations
The registry record reports 25 outcome measures and identifies blood alcohol concentration as the primary outcome. It also names horizontal gaze nystagmus, the walk and turn test, and the one leg stand test as secondary outcomes. The record does not provide a multiplicity plan describing which comparisons were primary, whether secondary outcomes were confirmatory or exploratory, or whether any adjustment for multiple testing was intended.
Multiplicity matters because examining many outcomes or comparisons can increase the chance of finding an apparently notable result by chance. In general, analysis plans can address this by defining a limited set of primary tests, adjusting thresholds, or clearly labeling other analyses as exploratory. The registry record does not report whether any of these approaches was used. It also reports zero analyses, so no outcome-specific estimates or test results are available for review.
Missing-data methods are not reported in the registry record. It does not state whether all enrolled participants contributed data to each outcome, how missing measurements were handled, or whether any sensitivity analyses were conducted. The analysis population is also not reported. The registry’s enrollment figure does not establish how many participants contributed usable observations to each condition or time point, and no such count should be inferred from enrollment alone.
These omissions limit assessment of the robustness and completeness of the results. Without analysis-population details, missing-data handling, and a multiplicity strategy, readers cannot evaluate whether reported estimates—if available—would represent all enrolled participants or a selected subset, or how to interpret multiple outcome comparisons. Those details are not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Within Group Four Condition Comparison | 0 | 7 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Within Group Four Condition Comparison | 0 of 7 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Within Group Four Condition Comparison | 2 of 7 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Within Group Four Condition Comparison |
|---|---|---|
| nausea | Injury, poisoning and procedural complications | 2 of 7 |
The registry record lists a within-group four-condition comparison with seven at risk for the serious-event category and zero serious adverse events. For other adverse events, it lists seven at risk and two events. It lists zero deaths. These are the safety counts recorded for the reported group.
The categories should be kept separate: the two other adverse events are not listed as serious adverse events. The record does not provide descriptions of those events, their timing, their relationship to a study condition, or whether any participant experienced more than one event. It also does not explain why the at-risk count is seven, or how that count relates to the enrollment figure. That denominator information is not reported in the registry record.
These counts are descriptive and do not establish a comparative safety difference among the four conditions. The study is not described as a randomized comparison between separate groups, and the safety information is not broken out by condition. With no such breakdown or analysis, the counts cannot identify whether an event was associated with beverage ethanol, e-cigarette liquid, their combination, or neither. They also do not address the primary blood alcohol concentration endpoint.
Zero recorded serious adverse events should be read as the count reported in the registry, not as proof that serious events are impossible. The registry entry does not give further details needed to judge the completeness of safety ascertainment.
12. What the Result Does, and Does Not, Mean
The study addresses a specific measurement question: whether blood alcohol concentration differs when an ethanol-containing e-cigarette is used rather than an e-cigarette without ethanol, in the context of four combinations of beverage and e-cigarette-liquid ethanol. The registry record provides the outcome definition, the session structure, and the timing of blood collection and e-cigarette use. It does not provide the primary endpoint results.
As a result, the record does not establish the direction or size of any difference in blood alcohol concentration. It does not show whether estimates were precise, whether any differences were statistically compatible with no difference, or whether the observed data supported one interpretation over another. No numerical result should be inferred from the study objective or its completed status.
The study’s broader stated purpose includes breath and oral-fluid testing, field sobriety tests, and other tests of sobriety. The registry names three secondary outcomes, but does not report their results. Therefore, the record cannot establish whether or how the four conditions affected those tests. Nor can it support conclusions about impairment in general; the listed endpoint and objectives do not substitute for reported analyses of those outcomes.
The within-group design may permit comparisons among conditions using repeated observations from participants, but the analysis methods are not reported. Without estimates, confidence intervals, analysis details, and information about missing measurements, the precision and reliability of any condition comparison cannot be assessed. The registry entry also does not report a multiplicity strategy for the 25 outcome measures.
The appropriate conclusion is limited: the registry describes a completed study designed to examine these questions, but does not report results that answer them. This is an absence of reported evidence in the registry record, not evidence that the conditions produced identical results or that no effect occurred.
13. Why This Trial Matters Statistically
This study is statistically interesting because it combines two potential sources of ethanol exposure in a repeated, four-condition design. Varying the beverage and e-cigarette liquid across conditions creates a structure in which the individual components and their combination may be relevant. That makes the exact contrast important: a comparison that changes both components answers a different question from one that changes only the e-cigarette liquid.
The timing of measurements is also central. Blood alcohol concentration was collected at multiple times in relation to drinking and e-cigarette use. Those measurements can support questions about both condition differences and changes over time, but the analysis must account for the relationship among repeated observations. The record describes the schedule and Latin-square session ordering, yet does not explain the statistical method or how order-related effects were assessed.
The record also illustrates why design information and outcome reporting are both necessary. A clearly described objective and measurement schedule do not show what the observed data were. Without condition-specific estimates and measures of uncertainty, readers cannot assess effect magnitude, precision, or the compatibility of the findings with different explanations. The record’s 25 outcome measures make a stated multiplicity strategy especially useful for understanding which comparisons were planned and how they should be interpreted.
Finally, the entry separates study completion from evidence of a result. It reports completed status, but lists no analyses and does not report the primary endpoint estimates. That distinction matters in clinical research: a completed design describes what was undertaken, while statistical conclusions require transparent results and analysis methods. The registry record is informative about the question and design, but not about the answer.
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.
A central limitation for interpreting this trial is that the registry record does not report the primary outcome values. It identifies blood alcohol concentration as a mean with standard deviation and specifies measurement timing, but gives no condition-level summaries or comparisons. The magnitude and precision of any differences therefore cannot be assessed.
The record also does not report the statistical analysis plan or methods. It does not identify the model, the planned contrasts, how repeated measurements were handled, whether baseline was used for adjustment, or whether the analysis considered time-by-condition patterns. Although sessions were Latin-square ordered, the record says session order was not recorded because it was considered irrelevant to outcomes; it does not provide an assessment of potential period or carryover effects.
The entry reports 25 outcome measures but does not describe a multiplicity strategy. It names several secondary outcomes without reporting their estimates or analyses. Missing-data methods and analysis populations are not reported, so it is not possible to assess how complete the observations were for the four conditions or the scheduled measurement times.
The safety information is limited to aggregate counts and does not describe events or separate them by condition. The relationship between the listed at-risk count and enrollment is not reported. The study is not presented as a randomized comparison between separate groups, so the condition contrasts should not be interpreted as a randomized parallel-arm comparison.
Finally, the planning assumptions described in the registry use equal allocation between two arms, while the trial is described as a within-group four-condition design. These planning illustrations do not establish the adequacy of the actual study design, and they are not observed power. The registry record does not report a trial-specific sample-size justification.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Impact of Oral Ethanol and Vaped Ethanol on the Evaluation of Impairment — NCT04522973.
- Registry record last updated 2026-01-14; status last verified 2025-12.
- Results first posted 2025-11-05.
- 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.
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18. Record Summary
The registry record describes a completed, single-group, within-group study titled The Impact of Oral Ethanol and Vaped Ethanol on the Evaluation of Impairment, sponsored by Virginia Commonwealth University. It lists an enrollment of 12 and a four-condition design varying ethanol in the beverage and e-cigarette liquid. Participants completed four sessions arranged in Latin-square order and separated by at least 48 hours.
Blood alcohol concentration, measured as percent alcohol, is the primary outcome. Blood collection was scheduled before drinking and at 0, 40, 55, 200, and 215 minutes after drinking; e-cigarette use was scheduled at 50 and 210 minutes. The registry also names horizontal gaze nystagmus, the walk and turn test, and the one leg stand test as secondary outcomes, and reports 25 outcome measures.
The study status is completed, but the registry record reports zero analyses and does not provide primary endpoint results, estimates, or uncertainty intervals. It lists zero serious adverse events, two other adverse events, and zero deaths in the reported group. The record does not provide further event details or a statistical analysis plan.