Effects of Acetate and Alcohol on Brain Function: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Acetate and Alcohol on Brain Function (NCT02542150), a randomized na study. The primary outcome is Change in Cerebral Blood Flow as Measured With Arterial Spin Labeling.

2. Clinical Question

The study’s broad question is how alcohol and acetate, a metabolite of alcohol, affect brain function. Its named primary outcome is change in cerebral blood flow measured during functional magnetic resonance imaging (fMRI) using arterial spin labeling. The registry record does not give a more specific hypothesis about the direction or size of an expected change.

The question is therefore clearer as a study aim than as a fully specified statistical comparison. The outcome is named, and exposure descriptions are recorded, but the analysis population, comparison structure, and results are not reported in the registry record. The record also notes that the primary outcome has several categories or time points and was not reduced to one comparison. This prevents a single effect estimate from being identified from the posted information.

3. Trial Design

The registry describes a randomized, single-masked, parallel study, with enrollment of 24. The study is marked completed. Its listed phase is NA. The sponsor is University of Colorado, Denver. The study start is recorded as 2015-09, and primary completion as 2017-03-31.

The named interventions are acetate and alcohol. According to the arm descriptions, IV acetate was given during the magnetic resonance scan, while jello shots were given before the scan in the alcohol arm. The adverse-event record separately identifies an IV placebo group associated with the acetate arm and an oral placebo group associated with the alcohol arm. The registry record does not explain the overall allocation of participants among all groups or specify which groups were included in each primary-outcome comparison.

Randomization is intended, in general, to reduce systematic differences between assigned groups at the outset. A parallel design generally means participants are assigned to a group and assessed under that assignment rather than crossing through multiple study conditions. Those are general descriptions; the registry record does not provide further detail about sequence generation, allocation concealment, or the specific implementation of the parallel design.

Single masking indicates that some aspect of study assignment was masked, but the registry record does not identify who was masked or how masking was maintained. The record also does not report the eligibility criteria, participant characteristics, recruitment setting, or whether participants could receive other study procedures beyond those described.

The primary outcome is titled “Change in Cerebral Blood Flow as Measured With Arterial Spin Labeling.” Its timeframe states that the fMRI scan would be scheduled for 1-3 weeks after enrollment and that the total visit would be about 6 hrs. The registry record does not specify a more detailed visit schedule or describe how the timing of exposure and imaging was handled beyond the arm descriptions.

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

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 Change in Cerebral Blood Flow as Measured With Arterial Spin Labeling, measured over fMRI scan will be scheduled for 1-3 weeks after enrollment. Total visit will be about 6 hrs..

The primary endpoint is change in cerebral blood flow measured using arterial spin labeling during functional magnetic resonance imaging. The registry gives the unit as cc/100 mg/min and identifies the outcome as a continuous measure summarized by a mean with standard deviation. The description says the reported data reflect best efforts to quantify the collected image data.

Cerebral blood flow is a physiological measure of blood moving through brain tissue. In general, measuring it during brain imaging can provide an outcome relevant to a study asking how an exposure relates to brain function. Arterial spin labeling is an imaging approach used to estimate blood flow; the registry names it as the measurement method but does not provide technical acquisition or image-processing details.

The endpoint title refers to change, but the registry record does not specify the exact reference measurement, formula for change, or analysis time point. Its timeframe says the fMRI scan would be scheduled for 1-3 weeks after enrollment, with a total visit of about 6 hrs. Those scheduling details do not, by themselves, identify how change was calculated or which observation was used in the analysis.

No analyzed mean, standard deviation, group contrast, or uncertainty estimate for this endpoint is reported in the registry record. Consequently, the endpoint’s measurement purpose can be described, but its observed values and comparative results cannot be interpreted from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary outcome as continuous, with the mean as the summary parameter and standard deviation as the dispersion measure. These choices are common for outcomes recorded on a quantitative scale. They provide a way to describe a group’s central value and the variability of observations, but they do not by themselves specify the statistical model or the comparison of interest.

What does a mean describe?

In general, a mean is the arithmetic average of observed values. For an imaging outcome, a group mean can summarize cerebral blood flow or change in cerebral blood flow for participants included in that group’s analysis. A mean is most informative when interpreted alongside the measurement scale, the analysis population, the timing of assessment, and the variability of the observations. The registry record gives the unit as cc/100 mg/min, but does not report a mean for any group.

What does the standard deviation add?

In general, the standard deviation describes how dispersed observations are around their mean. A relatively large spread indicates that individual values vary more around the average; a smaller spread indicates that values are more concentrated. It is not the same as the uncertainty in the estimated mean or in a difference between groups. The registry record identifies standard deviation as the dispersion measure but does not post its value for the primary outcome.

How would a comparison be interpreted?

In general, a treatment comparison needs a clearly defined contrast, such as a difference between group means at a specified time or a difference in changes from a reference measurement. The endpoint title uses the word “change,” but the registry record does not define the reference measurement or state the primary contrast. It also does not identify a single comparison among the categories or time points mentioned in the outcome note.

A confidence interval, in general, describes a range of values compatible with an estimate under the assumptions of the analysis. Its width reflects precision: a narrower interval indicates more precision than a wider one, considered on the same scale and under comparable methods. A p-value addresses compatibility of the data with a specified null hypothesis under a statistical model; it does not measure the size or clinical importance of an effect. Neither a confidence interval nor a p-value for the primary outcome is reported in the registry record.

Why do analysis details matter?

For a randomized study, a comparison should be interpreted in light of the assignment structure and the participants included. An analysis based on the assigned groups generally answers a different question from one that excludes participants or reclassifies them according to exposure received. The registry record does not report the primary analysis population or the analytic handling of participants who may not have completed imaging.

The record says the study was single-masked and parallel, but does not name the masked parties, describe allocation procedures, or provide the statistical model. It also does not report whether the outcome was adjusted for baseline values or other variables, how repeated measurements were treated, or how missing imaging data were handled. Such details can affect both the estimate and its uncertainty, so they should not be assumed.

What does the outcome note imply?

The registry indicates that the primary outcome has several categories or time points and was not reduced to one comparison. This means the record does not supply a single primary-outcome estimate to interpret. In general, when a study considers multiple outcomes, categories, or times, the analysis plan should clarify which comparisons are primary and how the risk of chance findings is addressed. The registry record does not report that plan or any multiplicity adjustment.

Multiplicity concerns arise when several hypotheses are tested or several estimates are examined. In general, examining more comparisons can increase the chance that at least one appears notable by chance alone. This does not establish that multiplicity affected this study; it explains why the planned comparison set and any adjustment matter. Those details are not reported in the registry record.

What can sample-size calculations tell readers?

In general, a sample-size calculation is a planning exercise based on assumptions about the outcome, target effect, variability, significance threshold, power, and allocation. It is not a result observed in the trial and should not be described as observed power. Any planning illustration based on an observed effect is particularly dependent on the estimate used and is not a substitute for the study’s own design justification.

The registry record includes a description of planning assumptions for illustrative calculations, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect and distinguishes participant-per-arm calculations from total event calculations for time-to-event outcomes. However, no analyzed primary effect is posted, and the record does not provide the trial’s own sample-size justification. These planning assumptions therefore do not establish the study’s achieved precision or power.

In short, the statistical labels clarify how the endpoint was intended to be summarized, but they do not replace estimates, intervals, or a defined comparison. With 0 analyses reported, the primary outcome cannot be quantitatively assessed from the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record does not report the primary analysis population, the handling of missing outcome data, or the approach to multiplicity. It also does not report whether all randomized participants were included in the primary analysis or whether any participants were excluded from imaging or analysis. The endpoint population field is blank.

The primary outcome note states that the outcome has several categories or time points and was not reduced to one comparison. The record does not identify those categories or time points, state which comparison was intended to be primary, or describe whether any adjustment was planned for multiple comparisons. In general, multiplicity matters when several hypotheses or outcome contrasts are assessed, because interpretation of isolated results can be affected by the number of comparisons considered. No adjustment method can be inferred from the registry record.

Missing-data handling also matters in general because incomplete outcome measurements can change which participants contribute to an estimate and may affect its precision or interpretation. The registry record does not state whether missing scans occurred, how missing values would be handled, or whether sensitivity analyses were planned. That absence should not be taken as evidence that data were missing or complete; the information is not reported in the registry record.

Although the record describes randomization and masking, it does not report an analysis plan detailed enough to determine how assignment, multiple categories or times, or missing observations were incorporated into an outcome estimate. No primary analysis results are posted, so the effects of these choices cannot be assessed.

11. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event record lists four groups: the Acetate Arm, IV Placebo (Acetate Arm), Alcohol Arm, and Oral Placebo (Alcohol Arm). Each lists 12 participants at risk for serious adverse events and 12 at risk for other adverse events. Serious adverse events affected 0 participants in each listed group. Other adverse events affected 1 participant in the Acetate Arm and 0 participants in each of the other listed groups. Deaths are recorded as 0 in every group.

These are counts recorded in the registry, not estimates of comparative risk. The record does not identify the type of the single other adverse event, and the serious-event list has no terms recorded. It also does not provide event descriptions or timing that would clarify the clinical context. The registry record does not state whether the listed counts include all events or only participants with at least one event.

In general, a count of participants with an event is different from a count of total event episodes, since one participant can experience more than one event. These entries should therefore be read according to the registry’s participant-at-risk and affected-participant fields, not as a complete account of event frequency or severity. Small group counts and the absence of additional detail limit what can be concluded from these safety entries.

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

The record establishes that a completed randomized, single-masked, parallel study was registered to examine the effects of acetate and alcohol on brain function. It identifies cerebral blood flow measured with arterial spin labeling as the primary outcome and describes the exposure procedures for the acetate and alcohol arms. It also records placebo groups in the adverse-event listing.

What the posted information does not establish is the direction or magnitude of any primary-outcome difference. No analyzed primary endpoint values or comparison are reported, and the record gives an analysis count of 0. It provides no confidence interval or p-value for cerebral blood flow. The outcome note states that several categories or time points were not reduced to one comparison, so a single result cannot be recovered from the registry entry.

This does not mean that the groups had the same outcome, and it does not mean that an effect was absent. It means the primary result is not available in the registry record for statistical interpretation. The intended study question and the existence of a registered outcome are not substitutes for analyzed outcome data.

The safety entries report no serious adverse events and no deaths in the listed groups, and one other adverse event in the Acetate Arm. Those counts provide a limited description of what was entered in the adverse-event record. They do not, by themselves, establish comparative safety, characterize the event, or provide a complete account of adverse experiences.

Any planning sample-size illustration should be understood as a hypothetical calculation based on assumptions, not as observed power or evidence that the study could detect a particular effect. Because the registry record does not report the primary outcome estimate, a planning calculation based on an observed effect cannot be interpreted as an outcome finding. The trial’s own sample-size justification is not reported in the registry record.

The appropriate conclusion is limited: the registry documents the study design, intended measurement, and selected safety counts, but does not provide the analyzed primary results needed to judge the cerebral blood flow comparison.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between a registered question and a reported result. The record names a continuous imaging endpoint, specifies its unit and summary measure, and describes a randomized, single-masked, parallel design. Yet the primary outcome analysis count is 0, and no analyzed group estimates or contrasts are reported. A clear outcome label does not by itself permit an effect estimate to be interpreted.

The record also illustrates why a comparison must be specified precisely. The study lists acetate and alcohol interventions, while the adverse-event listing includes placebo groups associated with each. The primary outcome note refers to several categories or time points but does not reduce them to one comparison. Without the analysis population, comparison definition, and time-point handling, readers cannot determine what single estimand the result would represent.

For researchers, the entry highlights the value of reporting group-level estimates with measures of uncertainty, along with the planned contrast and analysis population. Reporting how missing observations and multiple comparisons are handled helps readers distinguish the primary inference from exploratory comparisons. Those details are not reported in the registry record.

The safety entries likewise show the limits of counts without descriptions. Counts of affected participants are useful for basic reporting, but event terms, timing, severity, and a clear description of what was counted are needed for deeper interpretation. The record provides only limited event detail.

The statistical significance of this study’s intended question cannot be judged from the registry record because no primary analysis is posted. Its importance is methodological: it shows why transparent outcome reporting must extend beyond stating what was measured to include what was estimated, how it was analyzed, and how precisely it was estimated.

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 main limitation for interpreting this specific trial is that no analyzed primary-outcome results are reported in the registry record. The record names change in cerebral blood flow as the primary endpoint, but supplies no group means, standard deviations, contrast, confidence interval, or p-value. The analysis count is 0. The outcome note also says that several categories or time points were not reduced to one comparison.

Important design and analysis details are not reported in the registry record. These include the population characteristics and eligibility criteria, the exact primary comparison, the analysis population, the reference measurement used to calculate change, the model, any covariate adjustment, missing-data procedures, and the handling of multiple categories or times. The endpoint population field is blank. Masking is described as single, but the masked party is not identified.

The intervention descriptions provide limited procedural context: IV acetate was given during the scan, and jello shots were given before the scan in the alcohol arm. The registry record does not describe dose, timing in greater detail, or the allocation structure across the listed intervention and placebo groups. These details should not be inferred from the arm names.

The registry lists an enrollment of 24 and records 12 participants at risk for each adverse-event group. It does not provide participant-level outcome information or explain how those safety denominators relate to the primary analysis. Safety reporting is also limited: the record includes affected-participant counts but does not identify the one other adverse event or provide event-level descriptions.

Finally, the registry record does not report the trial’s own sample-size justification. Its stated planning assumptions are illustrative and do not replace an observed primary-outcome estimate or its uncertainty. These limitations leave the design aim understandable but prevent quantitative assessment of the primary comparison.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Acetate and Alcohol on Brain Function — NCT02542150.
• Registry record last updated 2021-06-25; status last verified 2021-06.
• Results first posted 2021-06-25.
• 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

NCT02542150 is a completed, randomized, single-masked, parallel study sponsored by University of Colorado, Denver. It lists acetate and alcohol as interventions and describes IV acetate during a magnetic resonance scan and alcohol given as jello shots before the scan. The primary outcome is change in cerebral blood flow measured with arterial spin labeling during fMRI, summarized as a mean with standard deviation and measured in cc/100 mg/min.

The registry record reports enrollment of 24 and states that the scan was to be scheduled for 1-3 weeks after enrollment, with a total visit of about 6 hrs. It does not post analyzed primary-outcome results; the analysis count is 0, and the outcome note says several categories or time points were not reduced to one comparison. The adverse-event record reports 0 serious adverse events and 0 deaths in each listed group, with 1 other adverse event in the Acetate Arm and 0 in the other listed groups. The primary comparison and trial-specific sample-size justification are not reported in the registry record.