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 A Comparison of Propofol Versus Midazolam to Sedate Critically Brain Injury; Measurement of Cytokine Response and Assessment of Function (NCT01712477), a randomized phase 4 study. The primary outcome is Neuropsychologic Outcome.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01712477 |
| Phase | Phase 4 |
| Condition | Traumatic Brain Injury |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Michigan State University |
| Results posted | Yes |
2. Clinical Question
Population
Mechanically ventilated patients with traumatic brain injury who required sedation. The study description also proposed comparing patients with elevated blood alcohol levels with those whose levels were normal.
Intervention
Intravenous propofol sedation during mechanical ventilation.
Comparator
Intravenous midazolam sedation during mechanical ventilation, at variable doses to achieve adequate sedation.
Primary question
Whether the two sedation regimens differed in neuropsychological outcome, assessed as the extent of functional deficits from traumatic brain injury at 30 days.
The registry describes a prospective randomized pilot study of sedation in patients with traumatic brain injury. Its stated scientific aims extended beyond the primary neuropsychological outcome. The investigators planned to compare cytokine patterns at specified post-traumatic time points between patients receiving propofol and midazolam, and to examine cytokine response according to blood alcohol level. Neuropsychological testing was intended to assess the extent of brain injury and recovery.
These aims define questions the study planned to investigate; they are not findings. The registry says only one participant was enrolled and data analysis for the primary outcome was not completed. It does not report a comparative neuropsychological result, a cytokine result, or an analysis of the blood alcohol subgroups. Consequently, the clinical question can be described from the study objectives, but the registry record does not provide an answer about differences between the sedation groups.
3. Trial Design
The registry identifies this as a Phase 4 study, with randomized allocation and no masking. It describes the study as a prospective randomized controlled pilot study. At the same time, the record labels its model as single group, while listing propofol and midazolam interventions and describing separate arms for those regimens. These design fields do not align into a clear account of how participants were allocated. The registry does not report an allocation sequence, concealment procedures, or the number of participants assigned to each regimen.
The study concerned patients with traumatic brain injury who were already critically ill and required sedation during mechanical ventilation. The propofol description specifies intravenous sedation during ventilation. The midazolam description specifies intravenous sedation at variable doses to achieve adequate sedation. The registry does not report detailed dosing rules, treatment duration, or other co-interventions.
The recorded enrollment was 1, and the study status is terminated. The study began in 2011-11, with primary completion recorded as 2014-11. These dates and status describe the registry record; they do not explain why the study ended or establish when any individual assessment occurred. The reason for termination is not reported in the registry record.
The primary outcome was Neuropsychologic Outcome, with a 30 days timeframe and a description focused on functional deficits from the underlying brain injury. Cytokine levels correlating to extent of injury are listed as a secondary outcome. The registry lists two outcome measures, but reports no completed analysis for the primary outcome. It does not report the planned sample size, recruitment targets, or a rationale for the enrollment ultimately recorded.
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 | Intravenous Sedation With Propofol |
|---|---|
| STARTED | 1 |
| COMPLETED | 0 |
| NOT COMPLETED | 1 |
Analysis population for the primary outcome, as defined in the registry: Only one participant was enrolled and data analysis was not completed
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 | Intravenous Sedation With Propofol |
|---|---|---|
| Participants analysed | 1 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 1 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United States | participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Neuropsychologic Outcome, measured over 30 days.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is named Neuropsychologic Outcome. The registry describes it as the extent of functional deficits from the underlying traumatic brain injury, assessed at 30 days. Neuropsychological assessment can capture aspects of functioning that are not represented by a single laboratory measure; in this study, it was intended to characterize injury and recovery. That makes it conceptually distinct from the secondary focus on cytokine levels, which concern biological responses to tissue injury.
The endpoint is relevant to the study’s stated question because the investigators sought to compare patient outcomes following sedation with propofol or midazolam. However, the registry does not identify a specific neuropsychological instrument, scoring rule, threshold, or summary measure. Those measurement details are not reported in the registry record. Without them, a reader cannot tell which cognitive or functional domains were assessed or how multiple test results, if any, would have been combined.
The record states that only one participant was enrolled and that data analysis was not completed. It therefore supplies no group-level endpoint estimate, measure of uncertainty, or comparison between regimens. The planned 30-day assessment timeframe should not be mistaken for a reported observation or completed follow-up result. The endpoint’s intended meaning can be described, but its observed value and any treatment contrast are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the registry does not contain a completed comparative result for the primary neuropsychological outcome. It records one enrolled participant and explicitly states that data analysis was not completed. There is therefore no reported estimate of functional deficits at 30 days by sedation regimen, no estimate of the difference between regimens, and no confidence interval or significance test for that comparison. The posted record cannot establish whether the regimens produced similar or different measured outcomes.
The study’s randomized designation describes its intended or recorded design feature, not a result. With one participant enrolled, and without an allocation result or completed analysis, the registry does not show how randomization was implemented or whether the participant received propofol or midazolam. The record lists an adverse-event group for propofol, but that does not supply a primary efficacy result. Nor does the separate single-group model label resolve the apparent mismatch between the randomized designation and the listed two-regimen arms.
The planned cytokine comparisons likewise have no reported findings. Cytokines are described in the study rationale as biological responses to injury, and the study aimed to compare their patterns over post-traumatic time points and by sedation regimen. The registry lists cytokine levels correlating to extent of injury as a secondary outcome, but gives no measured values, contrasts, or analyses. It also supplies no result for the proposed comparison by blood alcohol level. These are unreported outcomes, not negative findings.
General statistical interpretation: an estimate describes the size and direction of a measured contrast, while a confidence interval conveys the uncertainty around that estimate under the assumptions of the analysis. Neither is available for the primary comparison in the registry record. Without an estimate and its uncertainty, readers cannot assess precision or distinguish a small observed contrast from a potentially substantial one. A missing significance test is not evidence that the groups were equivalent.
The record’s status of terminated is a study status, not an outcome. The reason for termination is not reported in the registry record, so no explanation should be inferred. Likewise, the record does not report whether any interim analysis took place, how missing observations were handled, or whether the investigators modified the planned analyses. The defensible conclusion is limited: a small pilot study was registered with a randomized comparison and several planned outcomes, but the registry reports one enrollee and no completed primary outcome analysis.
9. Statistical Methods Explained
Statistical interpretation depends first on what was measured, in whom, and according to which comparison. The registry identifies a 30-day neuropsychological outcome in patients with traumatic brain injury who required sedation during mechanical ventilation. It lists propofol and midazolam regimens, and describes cytokine response and blood alcohol status as additional interests. However, no completed statistical analysis is reported for the primary outcome. Methods can therefore be discussed only as general concepts and in relation to what the registry does or does not document.
What would a randomized comparison estimate?
General explanation: in a randomized study, a comparison of outcomes between assigned groups is intended to estimate the difference associated with assignment to the regimens, subject to the design and analysis assumptions. Random allocation can reduce systematic differences between groups when adequately implemented and when enough participants are included. The registry labels allocation randomized, but it does not describe the allocation process or report the distribution of enrolled participants between the two regimens. With one participant enrolled and no completed outcome analysis, it provides no group comparison to interpret.
The listed model is single group, despite the randomized designation and two described interventions. That inconsistency matters because the statistical model should match the actual structure of the data and the question being estimated. The registry does not explain the discrepancy. It is not possible to infer from these labels alone whether the intended analysis was a between-group comparison, a single-group description, or another approach.
How should an outcome estimate be read?
General explanation: a point estimate is a compact summary of the observed outcome or contrast. Its interpretation depends on the endpoint’s scale, the direction of scoring, and the population analyzed. A confidence interval gives a range of values compatible with the data and the chosen statistical procedure, under its assumptions. A narrow interval generally indicates greater precision than a wide interval, but an interval is not a guarantee that the true value lies within it. The registry reports no point estimate or confidence interval for neuropsychological outcome, so neither the magnitude nor precision of a treatment contrast can be assessed.
The endpoint description identifies functional deficits but does not name an assessment instrument or specify how the result was scored. Different instruments or scoring rules can have different scales and interpretations. The exact measurement approach, the handling of multiple tests, and the prespecified summary are not reported in the registry record. Those omissions prevent detailed evaluation of endpoint construction and statistical modeling.
Why does the small enrollment matter?
General explanation: statistical precision depends on the information available in the data, including the number of observed participants and the variability of the outcome. Very limited data can leave estimates highly uncertain, and a comparative analysis may not be feasible if there are too few observations across the groups. Here the registry records one enrollee and says that primary outcome analysis was not completed. This is not a completed trial estimate with low precision; it is an absence of a reported analysis.
Any sample-size figures are planning illustrations, not observed power. The stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. The record does not report a trial-specific sample-size justification. Because no completed primary outcome effect is reported, the registry record does not give a basis for interpreting a primary-outcome effect estimate or its precision. Such planning assumptions should not be mistaken for evidence that the study had a particular chance of detecting a clinically meaningful difference.
What role could cytokine analyses play?
General explanation: biological measurements taken at multiple time points can show patterns over time, but the analysis must account for how observations from the same participant are related. Treating repeated observations as independent when they are correlated can make uncertainty appear smaller than it is. The study description refers to cytokine patterns at specific post-traumatic time points, but the registry does not specify those time points, the cytokines measured, the analysis model, or any results. No assumptions about those methods should be made.
The study also proposed comparisons by elevated versus normal blood alcohol levels. A subgroup analysis can be less precise than an overall comparison because it uses fewer observations, and subgroup differences require careful interpretation. The registry does not report subgroup counts, definitions, analysis plans, or findings. No conclusion about subgroup response can be drawn from the stated objective alone.
What cannot be evaluated statistically?
The registry does not report an analysis population, treatment adherence, outcome missingness, imputation method, covariate adjustment, handling of protocol deviations, or a prespecified statistical analysis plan. It also reports no estimates, standard errors, confidence intervals, p-values, or completed analyses. These are not details that can be reconstructed from the study title or objectives. In their absence, statistical interpretation should stay with the design features and enrollment details that are actually recorded, rather than implying that an unreported analysis was conducted.
10. Multiplicity, Missing Data and Analysis Populations
The study description includes a primary neuropsychological outcome, a secondary cytokine outcome, multiple planned post-traumatic assessment times, and a proposed comparison according to blood alcohol level. When studies assess multiple outcomes, time points, or subgroups, the chance of obtaining a seemingly notable result by chance can increase if many tests are conducted. General statistical practice may address this through prespecified outcome hierarchies, adjustment procedures, or cautious interpretation. The registry does not report a multiplicity strategy, so it is not possible to say whether or how this issue was addressed.
There is no reported primary outcome analysis, and the registry lists zero analyses. It does not report whether the planned comparisons were performed, whether any interim analyses occurred, or whether the analysis plan changed. Those details are not reported in the registry record; no particular approach should be inferred from the randomized designation or the stated objectives.
The record also does not describe missing-data handling or define an analysis population, such as all randomized participants or participants with observed outcome assessments. With one participant enrolled, the registry states that primary data analysis was not completed, but it does not describe the participant’s follow-up or whether any endpoint measurement was obtained. No assumption about missingness, exclusions, or imputation is warranted.
Consequently, neither multiplicity control nor missing-data methods can be evaluated from the posted results. The absence of a reported result is not a null result, and it does not establish that planned comparisons found no differences.
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 |
|---|---|---|---|
| Intravenous Sedation With Propofol | 0 | 1 | 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 |
|---|---|
| Intravenous Sedation With Propofol | 0 of 1 |
The registry lists an adverse-event group titled Intravenous Sedation With Propofol. In that group, 1 participant was at risk for serious adverse events and 0 were recorded as affected; 1 was at risk for other adverse events and 0 were recorded as affected. The death count is null, which is not the same as a recorded count of zero. No serious adverse-event terms are listed.
These counts describe the registry’s posted safety information, not a comparative safety analysis. The record does not give a corresponding midazolam adverse-event group in the listed details, and it does not provide enough information to compare event rates between regimens. With only one participant recorded in the listed propofol group, zero recorded events cannot establish that events are absent or that a regimen is safer. It also cannot support broad conclusions about the frequency of uncommon events.
The registry does not report event definitions, observation duration, severity grading details, or a fuller account of adverse-event collection. Those details are not reported in the registry record. The figures should therefore be read narrowly as the counts recorded for the listed group, with the stated at-risk denominators, rather than as proof of safety or a treatment effect.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a Phase 4 pilot study was registered to compare propofol and midazolam sedation in patients with traumatic brain injury requiring mechanical ventilation. It records randomized allocation, no masking, one enrolled participant, and terminated status. It also records a planned neuropsychological primary outcome at 30 days and a secondary focus on cytokine levels. These registry entries describe the study’s status and objectives; they do not constitute evidence of a comparative outcome.
The record does not report a completed primary analysis. There is no reported estimate of neuropsychological function by regimen, no treatment contrast, and no uncertainty interval. Thus, the posted information cannot show whether outcomes differed, whether they were similar, or how precise a possible difference might be. A missing result should not be interpreted as evidence of no difference or as proof of equivalence.
The same restraint applies to cytokines and the planned comparison by blood alcohol level. No findings for those aims are reported. The listed adverse-event counts concern a single propofol group and do not provide a regimen-to-regimen safety comparison. The termination status also does not explain why the study ended; the reason is not reported in the registry record.
General interpretation: a trial’s registration can clarify its intended question and design, while an analysis is needed to estimate outcomes and quantify uncertainty. In this case, the available record is informative about the intended research but insufficient to answer the clinical comparison. It should not be used to claim benefit, lack of benefit, equivalence, or comparative safety for either sedation regimen.
13. Why This Trial Matters Statistically
This record illustrates why design labels and results need to be read separately. The registry identifies randomized allocation and describes two sedation regimens, but also labels the model single group. Recognizing that mismatch prevents a reader from assuming that the recorded information fully specifies the comparison or analysis structure. The registry does not explain how the labels fit together.
It also demonstrates the distinction between a planned endpoint and an analyzed endpoint. Neuropsychological outcome at 30 days is identified as primary, and cytokine response is part of the study’s scientific rationale. Yet the record states that only one participant was enrolled and that primary outcome analysis was not completed. A well-described research question does not by itself produce an estimable treatment contrast.
The statistical lesson is not that an effect was small, absent, or uncertain in a particular quantified way. Rather, there is no reported primary effect estimate to interpret. Precision requires outcome data and an analysis; it cannot be assessed from the intended design alone. Similarly, a count of zero recorded adverse events in a single listed group does not provide comparative safety evidence.
For clinical researchers and biostatisticians, the record is a reminder to distinguish enrollment, completion, analysis, and interpretation. It is also a reason to scrutinize whether registry fields agree and whether measurement details, analysis populations, missing-data methods, and multiplicity plans are documented. Where those details are unavailable, transparent limits on interpretation are more informative than conclusions the data record cannot support.
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 most consequential limitation is that the registry reports only one enrolled participant and says the primary outcome analysis was not completed. It therefore offers no comparative estimate for the main question. The enrollment is too limited to support the planned group, time-point, or subgroup comparisons as reported, and no completed analysis is available to quantify uncertainty.
Several registry design fields are difficult to reconcile: allocation is identified as randomized, two sedation regimens are described, and the model is labeled single group. The record does not clarify the intended or implemented structure. It also does not report which regimen the enrolled participant received or how many participants were allocated to each arm.
Outcome measurement details are incomplete. Although neuropsychological outcome is described as functional deficits at 30 days, the instrument, scoring system, and aggregation approach are not identified. The cytokine description refers to specific post-traumatic time points but does not name them or specify the measured cytokines. Protocol details such as doses, treatment duration, and co-interventions are not fully reported.
The registry does not report a statistical analysis plan, a sample-size justification, analysis populations, missing-data methods, multiplicity handling, or interim analyses. It also does not provide completed outcome estimates or a reason for termination. These limitations restrict evaluation of both the planned methods and the results. They should not be filled in by assumptions about usual practice or by treating unreported findings as negative findings.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Comparison of Propofol Versus Midazolam to Sedate Critically Brain Injury; Measurement of Cytokine Response and Assessment of Function — NCT01712477.
- Registry record last updated 2025-09-10; status last verified 2020-09.
- Results first posted 2025-06-26.
- 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
NCT01712477 is a Phase 4 study sponsored by Michigan State University, listed as terminated. The registry records a start date of 2011-11, primary completion of 2014-11, and enrollment of 1. It describes a randomized comparison of intravenous propofol and midazolam sedation in mechanically ventilated patients with traumatic brain injury, while also labeling the model single group and reporting no masking.
The primary outcome is Neuropsychologic Outcome at 30 days, described as the extent of functional deficits from traumatic brain injury. Cytokine levels correlating to extent of injury are listed as a secondary outcome. The record states that analysis of the primary outcome was not completed. It reports no comparative efficacy result, no cytokine findings, and no reason for termination.
The listed propofol safety group records 0 serious and 0 other adverse events among 1 participant at risk for each category; the death count is null. These counts do not establish comparative safety. Overall, the registry documents the planned research question and limited enrollment, but does not provide an analyzed answer to the treatment comparison.