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 Midazolam Effect in Children Undergoing Voiding Cystourethrogram (VCUG) (NCT00894465), a randomized na study. The primary outcome is Anxiety Score From the Modified Yale Preoperative Anxiety Scale.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00894465 |
| Phase | NA |
| Condition | Vesicoureteral Reflux |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 44 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Washington University School of Medicine |
| Results posted | Yes |
2. Clinical Question
Population
Children undergoing a voiding cystourethrogram (VCUG), including children who had not previously undergone VCUG and children with a prior VCUG. The condition listed in the registry record is vesicoureteral reflux. The record does not report further eligibility details, such as an age range or the distribution of prior VCUG experience.
Intervention
Oral midazolam, identified as Versed in the arm description, administered before VCUG. The record describes its purpose as reducing anxiety and making the experience less traumatic; that purpose is not itself evidence of an observed effect.
Comparator
An oral placebo administered before VCUG. The arm descriptions state that both children without a previous VCUG and those with a previous VCUG could be in either treatment arm.
Primary question
How does anxiety, measured with the Modified Yale Preoperative Anxiety Scale, compare between the midazolam and placebo groups at the stated assessment times: in the waiting room, before catheterization, and after catheterization? The registry record does not report the outcome values or an analysis answering this question.
The trial question is about a measured anxiety score during the VCUG experience, rather than a clinical diagnosis or a later health outcome. The record also lists the State-Trait Anxiety Inventory as a secondary outcome. It does not report how that secondary measure relates to the primary scale, or how either outcome was intended to be analyzed across the assessment times.
3. Trial Design
The registry record describes a randomized, parallel-group study comparing oral midazolam with oral placebo before a VCUG. Masking is recorded as triple, but the record does not specify which groups of people were masked or how masking was maintained. The listed enrollment is 44. The arm descriptions include children with and without prior VCUG experience in both groups; the record does not report how many participants had each history.
The study is listed as terminated. Its recorded start is 2006-08 and its primary completion is 2009-06. The phase is listed as NA. The sponsor is Washington University School of Medicine. These registry entries describe the study record, not the reason for termination or the conduct of the trial. The reason for termination is not reported in the registry record.
The intervention descriptions identify the active treatment as oral midazolam and the comparator as oral placebo, both given before the procedure. The primary outcome is a mean anxiety score from the Modified Yale Preoperative Anxiety Scale, with assessments listed in the waiting room, before catheterization, and after catheterization. A secondary outcome is an anxiety score from the State-Trait Anxiety Inventory.
Although the registry identifies the primary outcome and its assessment times, it does not provide outcome summaries, treatment-effect estimates, confidence intervals, or tests of statistical significance. It lists no analyses. The reason given for not reducing the primary outcome to a single comparison is that it has several categories or time points. Consequently, the registry record does not establish which time-specific comparison, if any, was designated as the main treatment-effect estimate.
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 | Versed | Placebo |
|---|---|---|
| STARTED | 22 | 22 |
| COMPLETED | 22 | 22 |
| NOT COMPLETED | 0 | 0 |
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.
Population: All participants who signed consent were included in analysis population.
| Characteristic | Unit | Versed | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 22 | 22 | 44 | |
| Age, Categorical: <=18 years | Participants | 22 | 22 | 44 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 3.59 (SD 0.9) | 3.45 (SD 1.4) | 3.52 (SD 1.15) |
| Sex: Female, Male: Female | Participants | 22 | 20 | 42 |
| Sex: Female, Male: Male | Participants | 0 | 2 | 2 |
| Region of Enrollment: United States | participants | 22 | 22 | 44 |
6. Primary Endpoint
The registry lists the primary outcome as Anxiety Score From the Modified Yale Preoperative Anxiety Scale, measured over Waiting room, before catheterization, and after catheterization.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the anxiety score from the Modified Yale Preoperative Anxiety Scale. The record describes the scale as covering activity, vocalizations, emotional expressivity, apparent arousal, and use of parents. Four categories are scored from 1 to 4 points and one category from 1 to 6 points. The category scores are divided by their respective possible points and multiplied by 20 to produce a final score ranging from 20 to 100. Lower scores represent lower anxiety, while higher scores represent higher anxiety.
The listed assessment times are the waiting room, before catheterization, and after catheterization. Measuring anxiety at these stages can describe anxiety during different parts of the procedure, rather than treating the experience as a single undifferentiated moment. That is a general rationale for repeated assessment; the registry record does not report a specific rationale for selecting these times or a model for analyzing repeated scores.
The endpoint is recorded as a mean with standard deviation. In general, a mean describes the center of the observed scores, while a standard deviation describes their spread. Neither statistic can be interpreted as a treatment comparison without the corresponding group results and a defined comparison. The registry record does not report group means, standard deviations, or a treatment-effect estimate for this endpoint.
The State-Trait Anxiety Inventory is listed as a secondary outcome, but its scoring details and results are not reported in the registry record. The endpoint descriptions therefore identify what was intended to be measured, not what the trial found.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record does not report numerical results for the primary anxiety outcome. It gives no group means or standard deviations for the Modified Yale Preoperative Anxiety Scale and no estimate comparing midazolam with placebo. It also gives no confidence interval or significance test for the primary outcome. The available record therefore does not show the direction, size, or precision of any treatment-group difference in anxiety.
The primary outcome has assessments in the waiting room, before catheterization, and after catheterization. Without results at those times, it is not possible to tell whether the groups had similar or different scores at any particular stage, whether any difference changed over the course of the procedure, or how much variability was present. The registry specifically indicates that the outcome was not reduced to one comparison because it has several categories or time points. No analysis is listed to clarify how those repeated assessments were handled.
The secondary State-Trait Anxiety Inventory outcome is named, but the record does not report its results or analysis. It therefore cannot add a quantitative comparison to the primary measure in this record.
The registry lists enrollment of 44 and describes randomized allocation. Enrollment alone does not reveal how many participants contributed usable primary-outcome measurements, whether the groups remained balanced in the analyzed data, or whether any measurements were missing. The record does not report an analysis population, participant flow, or missing-data handling.
Safety information is also limited to the reported adverse-event counts. For the serious adverse-event category, the registry lists 0 affected among 22 at risk in the Versed group and 0 affected among 22 at risk in the placebo group. Those entries describe the recorded counts; they do not establish that every possible harm was assessed or captured. Other adverse events are also listed as 0 affected among 22 at risk in each group, but definitions and detailed event reporting are not present. Death counts are null, not numerical zeroes.
Any interpretation should distinguish an absent result from a result showing no difference. A missing estimate does not demonstrate that the groups were equivalent, and the lack of a reported significance test does not establish that an effect was absent. The record supports describing the design, endpoint, and recorded safety counts, but not drawing a conclusion about the effect of midazolam on anxiety.
9. Statistical Methods Explained
Randomization is a design method intended, in general, to reduce systematic differences between treatment groups by assigning participants through a chance process. It can support a fair treatment comparison when allocation is implemented as planned and outcome data are analyzed appropriately. The registry records randomized allocation, but does not report the sequence-generation or allocation-concealment procedures. It also does not report baseline characteristics that would show how the groups compared at the start.
The study is described as parallel-group: participants are assigned to a treatment group and the groups receive their respective interventions. The active intervention is oral midazolam before VCUG, and the comparator is oral placebo before VCUG. The record labels masking as triple. In general, masking is intended to limit the influence of treatment knowledge on care, measurement, or assessment. The registry does not identify which people were masked, how the placebo was matched, or whether masking was assessed.
The primary measure is continuous: it yields a numerical anxiety score. The endpoint is specified as a mean with standard deviation. In general, a mean is a summary of the average score, and a standard deviation describes how dispersed individual scores are around that average. To compare groups, an analysis would ordinarily need to define the comparison of interest and account for the relevant sources of uncertainty. No group summaries or inferential analyses are reported in the registry record, so there is no treatment estimate to explain.
A confidence interval is a general statistical way to express uncertainty around an estimated effect. Its width reflects the precision of that estimate under the analysis assumptions; it does not by itself indicate whether an effect is important. The registry record reports no confidence interval for the primary outcome. A p-value, when reported, addresses compatibility between data and a specified statistical model under a null hypothesis; it does not measure the probability that the null hypothesis is true or the size of an effect. No p-value for the primary outcome is reported.
The anxiety score is specified at the waiting room, before catheterization, and after catheterization. Repeated scores from the same participant are generally related, rather than independent observations. As a general statistical principle, an analysis of repeated measurements should account for that within-participant relationship. A model might also need to define whether the treatment comparison is made separately at each time or across time, and whether change over time is part of the question. The registry does not report a model, a covariance structure, or a prespecified contrast. No particular repeated-measures method can therefore be attributed to this trial.
Multiplicity is a concern in general when several treatment comparisons or outcome assessments can each be used to make a claim. Testing multiple times or outcomes without a plan can increase the chance of at least one apparently notable result. A prespecified primary contrast and an appropriate multiplicity strategy can clarify how evidence is interpreted. The record identifies several assessment times and a secondary anxiety outcome, but does not report a multiplicity plan or designate a single time-specific primary comparison.
The registry describes the primary outcome using means and standard deviations, but does not report a sample-size justification or a trial-specific statistical plan. A planning illustration based on a stated fraction of an observed effect is not the same as a sample-size calculation documented as part of the trial design. The listed illustration assumptions use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Such planning values are illustrative, not observed power, and do not establish what the investigators planned or what the trial could detect. The registry record does not report the trial's own sample-size justification.
Continuous outcomes may sometimes have distributions that depart from the assumptions of a simple normal model. General methods can address skewness, outliers, or other features, but the appropriate choice depends on the observed data and estimand. Over-dispersion is more commonly discussed for count outcomes: it means variability is greater than a model assumes, and ignoring it can make uncertainty appear too small. The primary endpoint is a score summarized as a mean and standard deviation, not a reported count outcome. The registry gives no distributional diagnostics or model details, so no claim about these assumptions can be made for this trial.
The most important limitation for statistical interpretation is the absence of posted outcome analyses. Without participant-level data or reported summary statistics, an independent recalculation from summary statistics is not possible. No recalculated effect, confidence interval, or significance test can be stated. The record also does not provide enough detail to assess whether the analysis followed a prespecified plan.
10. Multiplicity, Missing Data and Analysis Populations
The primary anxiety score is assessed at three listed stages: in the waiting room, before catheterization, and after catheterization. The registry record says the outcome was not reduced to a single comparison because it has several categories or time points. It does not identify one time point as the sole primary comparison, state whether the times were to be analyzed jointly, or report a plan to control the consequences of multiple comparisons. The State-Trait Anxiety Inventory is also listed as a secondary outcome, with no analysis or multiplicity strategy reported.
In general, multiplicity matters because examining several outcomes or time points can make an isolated result harder to interpret unless the analysis plan accounts for the number and purpose of the comparisons. A clear plan can distinguish a primary confirmatory comparison from supportive or exploratory analyses. The record does not report such a hierarchy or any adjustment procedure; this absence does not establish that no plan existed outside the registry record.
Missing-data information is not reported in the registry record. There is no participant flow by treatment group, number of completed anxiety assessments, description of withdrawals, or explanation of how incomplete measurements would be handled. The analysis population is also not reported. Consequently, it is not possible to determine whether all randomized participants were included in an analysis, or whether the reported enrollment corresponds to the population measured at each assessment time.
These omissions limit both reproducibility and interpretation. Repeated measures can be incomplete at some times while present at others, and the handling of those observations may affect the treatment comparison. Without reported analysis details, the reader cannot assess that issue for this trial.
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 |
|---|---|---|---|
| Versed | 0 | 22 | 0.0% |
| Placebo | 0 | 22 | 0.0% |
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 |
|---|---|
| Versed | 0 of 22 |
| Placebo | 0 of 22 |
For serious adverse events, the registry lists 0 affected among 22 at risk in the Versed group and 0 affected among 22 at risk in the placebo group. The record lists 0 other adverse events among 22 at risk in each group. These are the recorded counts and denominators; they are not an estimate of comparative risk with a reported confidence interval or statistical test.
A zero count in a registry entry means no affected participants were recorded for that category in the listed group. In general, it does not prove that an event is impossible or that every event would necessarily have been detected and reported. Interpretation depends on how events were defined, monitored, and collected. Those details are not reported in the registry record, and no serious-event terms are listed.
The death entries are null. A null entry is not the same as a recorded numerical zero, so the registry record does not support describing the death count as zero. The listed safety figures should be read as limited registry reporting, not as a complete assessment of all possible harms or as evidence about the primary anxiety outcome.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, triple-masked, placebo-controlled study was registered to examine oral midazolam before VCUG in children. It identifies the anxiety scale, its scoring direction, the assessment stages, a secondary anxiety outcome, and adverse-event counts. It also reports enrollment of 44 and a terminated status.
It does not establish whether midazolam reduced anxiety, whether the treatment groups differed, or whether any observed difference would have been large or precise. There are no primary-outcome means, standard deviations, treatment-effect estimates, confidence intervals, or significance tests in the registry record. The absence of those results must not be interpreted as a finding of no effect or as evidence that the groups were equivalent.
The listed serious adverse-event counts are zero in both groups, but safety interpretation remains limited by the absence of reported definitions and details about event ascertainment. The null death entries should not be converted into zero counts. In addition, the registry does not report missing-data handling or the analysis population, which prevents assessment of how much of the enrolled group contributed to each outcome assessment.
In general, a clinical trial's design and stated measures describe what investigators intended to compare, while results are needed to estimate what happened in the observed participants. The record offers the former but does not report the latter for the primary anxiety question. It is therefore appropriate to describe the registered comparison and the limits of the available information, but not to make a treatment-effect or clinical recommendation based on this record.
13. Why This Trial Matters Statistically
This trial illustrates why a registered outcome is not the same as a reported result. The primary endpoint is defined in detail, including what the anxiety scale measures, how its score is constructed, and when it is assessed. Yet the registry record lists no analyses and provides no outcome values. A well-described measure cannot answer a treatment question without results and a defined comparison.
The multiple assessment stages also show why the estimand—the precise treatment effect a study aims to estimate—matters. A comparison at one stage may address a different question from a comparison of overall anxiety across the procedure or a difference in change over time. The record does not specify which interpretation was intended. This makes it difficult to connect any hypothetical finding to a single, prespecified statistical question.
The record also illustrates the difference between safety counts and a complete safety analysis. A zero in a listed adverse-event category is informative as a registry entry, but its meaning depends on event definitions, observation, and reporting. Null death entries cannot be treated as numerical zeroes. Clear outcome definitions and complete reporting are important for interpreting both benefits and harms.
Finally, termination status and enrollment do not substitute for participant flow, analysis populations, or outcome reporting. Without these elements, readers cannot judge precision, missingness, or whether the planned comparison was carried out as intended. The statistical lesson is not about whether the intervention changed anxiety; this record does not show that. It is about the information needed to make a transparent, reproducible comparison.
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 registry record does not report primary-outcome results, despite defining the Modified Yale Preoperative Anxiety Scale and listing three assessment stages. It therefore does not allow a treatment-effect estimate or an assessment of statistical precision. No means, standard deviations, confidence intervals, or tests are reported for the primary measure.
The outcome is not reduced to a single comparison because it has several categories or time points. However, the record does not describe a repeated-measures strategy, specify a primary time-specific contrast, or explain how the multiple assessments would be interpreted together. The relationship between the primary scale and the secondary State-Trait Anxiety Inventory is not detailed.
Participant-level reporting is also limited. The registry does not provide baseline characteristics, allocation procedures, participant flow, the number with outcome data at each time, missing-data handling, or the analysis population. It does not report how many children had a prior VCUG, even though both prior and VCUG-naive participants are described in both treatment arms. These gaps restrict assessment of the groups and the completeness of follow-up.
The record lists the study as terminated but does not state why. It does not report which people were included in triple masking, how masking was implemented, or whether it remained intact. Its safety entries include zero recorded serious and other adverse events in each group, but event definitions and ascertainment procedures are not described. Death counts are null. These limitations are specific to the information recorded and do not establish what may have been documented elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Midazolam Effect in Children Undergoing Voiding Cystourethrogram (VCUG) — NCT00894465.
- Registry record last updated 2016-12-09; status last verified 2016-10.
- Results first posted 2016-12-09.
- 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
NCT00894465 is a randomized, parallel-group, triple-masked, placebo-controlled study of oral midazolam before VCUG in children. The registry lists enrollment of 44, identifies vesicoureteral reflux as the condition, and records the study as terminated. The primary outcome is the Modified Yale Preoperative Anxiety Scale score, assessed in the waiting room, before catheterization, and after catheterization. A State-Trait Anxiety Inventory score is listed as a secondary outcome.
The registry record lists no outcome analyses and reports no primary anxiety results. It therefore does not establish the direction or size of a treatment-group difference, or its precision. Serious and other adverse-event counts are listed as 0 among 22 at risk in each group; death entries are null. The reason for termination, analysis population, missing-data approach, and trial-specific sample-size justification are not reported in the registry record.