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 Dexamethasone and Block Duration in Upper Extremity (NCT01756573), a randomized na study. The primary outcome is Analgesia Duration.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01756573 |
| Phase | NA |
| Condition | Duration of Pain Relief |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 5 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Chicago |
| Results posted | Yes |
2. Clinical Question
Population
People enrolled in a study of upper extremity blocks. The registry lists enrollment as 5; further participant characteristics are not reported in the registry record.
Intervention
Dexamethasone mixed with bupivacaine, or dexamethasone given intravenously. The record describes these as separate study arms.
Comparator
Bupivacaine alone, described as the control arm.
Primary question
Does dexamethasone given with bupivacaine differ from intravenous dexamethasone in its effect on the duration of analgesia from an upper extremity block, as assessed over 72 hrs?
The study description frames the question around whether dexamethasone’s effect on block duration is local to the nerves or reflects a general analgesic effect. Comparing dexamethasone mixed with bupivacaine against intravenous dexamethasone is intended to address that distinction; the bupivacaine control arm provides another reference point.
The registry lists analgesia duration as the primary outcome. However, it states that the study was terminated prematurely because of lack of resources and participation, and that no outcome data were collected and no analysis was done. Consequently, the record cannot establish whether the treatment approaches differed, or estimate the size or precision of any difference.
3. Trial Design
The registry describes a randomized, quadruple-masked, parallel study. The listed interventions were bupivacaine alone, bupivacaine with dexamethasone, and intravenous dexamethasone. The arm descriptions identify bupivacaine alone as the control, dexamethasone mixed with bupivacaine as the local combination, and intravenous administration as the systemic approach.
Random allocation is intended to reduce systematic differences between treatment groups at the point of assignment. Masking is intended to limit the influence of knowledge about treatment assignment on care, reporting, or assessment. The registry identifies masking as quadruple but does not specify which roles were masked in the registry record. A parallel design assigns participants to a study arm rather than describing a crossover between treatments; further details of the allocation process are not reported in the registry record.
The listed enrollment is 5. The registry gives a study start of 2013-01 and a primary completion date of 2015-01, and records the status as terminated. Phase is listed as NA. The sponsor is the University of Chicago. The registry does not report a sample-size justification, the reasons for choosing the enrollment target, or further operational details of the planned conduct.
Most importantly for interpreting the design, the registry explicitly says that the study ended prematurely because of lack of resources and participation. It also states that no data were collected for the outcome measures and no analysis was done. Thus, the planned randomized comparisons did not produce an analyzable primary outcome result in the registry record.
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 | Bupivacaine | Bupivacaine With Dexamethasone | Intravenous Dexamethasone |
|---|---|---|---|
| STARTED | 3 | 1 | 1 |
| COMPLETED | 3 | 1 | 1 |
| NOT COMPLETED | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: study terminated prematurely due to lack of resources and participation- no data collected for Outcome measures and no analysis done
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 | Bupivacaine | Bupivacaine With Dexamethasone | Intravenous Dexamethasone | Total |
|---|---|---|---|---|---|
| Participants analysed | 3 | 1 | 1 | 5 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 3 | 1 | 1 | 5 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 | 0 |
| Sex/Gender, Customized: Female | Participants | 2 | 1 | 1 | 4 |
| Sex/Gender, Customized: Male | Participants | 1 | 0 | 0 | 1 |
| Region of Enrollment: United States | Participants | 3 | 1 | 1 | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Analgesia Duration, measured over 72 hrs.
| 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 titled Analgesia Duration, with a timeframe of 72 hrs. It is intended to measure how long pain relief associated with an upper extremity block lasts. Duration is relevant to the study’s question because the stated aim is to examine whether dexamethasone’s effect on block duration differs when it is mixed with bupivacaine versus given intravenously.
As a general statistical point, a duration endpoint can describe the time until a defined event, such as the end of analgesia. Its interpretation depends on how the event is defined, how it is measured, and how observations are handled when the event is not observed during follow-up. Those operational details are not reported in the registry record. The endpoint’s unit is also not specified.
The registry does not contain observed endpoint values or an analysis. Its outcome description says the study was terminated prematurely because of lack of resources and participation, with no outcome data collected. Therefore, the stated timeframe and endpoint name describe the intended measurement, not a reported estimate of analgesia duration.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted record does not report an estimated treatment effect for analgesia duration. It gives no group-level outcome values, measure of variability, confidence interval, or statistical test for the primary endpoint. The registry explicitly states that no outcome data were collected and no analysis was done. There is therefore no estimate in the record from which to assess the direction, size, or precision of a difference among the study arms.
Enrollment is listed as 5, and the status is terminated. The registry attributes premature termination to lack of resources and participation. These details explain why the intended comparison is unavailable, but the record does not provide enough information to determine how the enrollment was distributed across arms or what circumstances applied to individual participants.
In general, a confidence interval expresses the uncertainty around an estimated effect under a statistical model. A narrow interval would indicate greater precision than a wide interval, while an interval spanning a range of possible effects can leave substantial uncertainty. No confidence interval is reported for this trial, so there is no basis for describing the precision of a treatment effect. Likewise, no p-value is reported for the primary outcome; statistical significance cannot be assessed from the registry record.
The absence of an outcome analysis is not evidence that the treatments had the same effect, nor is it evidence that one approach performed better. It means the record supplies no primary outcome comparison. The small listed enrollment and early termination limit what can be learned from this record, but the central issue is more direct: there are no collected outcome data on which to base an efficacy estimate.
Safety figures are separately listed, including zero serious and other affected events in the posted group summaries. These figures do not substitute for the missing analgesia-duration results. The risk counts differ by group, and deaths are marked as null rather than reported as a numerical count. Safety entries should therefore be read as the registry’s posted adverse-event information, not as a result that resolves the primary research question.
9. Statistical Methods Explained
The methods recorded for this study are randomized allocation, quadruple masking, and a parallel model. The record does not describe a completed statistical analysis: it states that no outcome data were collected and no analysis was done. The concepts below explain, in general, what the design features and potential analyses mean; they should not be read as methods confirmed to have been applied to trial results.
What does randomization contribute?
In general, randomization assigns participants to study arms by chance. Its purpose is to make treatment groups comparable, on average, with respect to factors that could influence an outcome. Randomization does not guarantee balance in every individual study, and it cannot compensate for missing outcome data. The registry identifies the study as randomized, but details such as the sequence-generation method, concealment process, and allocation ratio are not reported in the registry record.
What is the role of masking?
Masking means that specified people involved in a study do not know which intervention a participant receives. In general, this can reduce the influence of treatment expectations on participant reports, clinical decisions, or outcome assessment. The registry labels this trial quadruple-masked but does not identify the masked roles or describe how masking was maintained. The label alone does not establish which procedures were used.
What does a parallel model mean?
In a parallel design, participants are assigned to a study arm and outcomes are compared across arms. Here, the registry lists bupivacaine alone, bupivacaine with dexamethasone, and intravenous dexamethasone. The intended scientific contrast concerns local administration with bupivacaine versus intravenous administration, with bupivacaine alone also listed as a control. The record does not report an analysis defining a specific pairwise contrast or an overall comparison.
How would an endpoint comparison be interpreted?
In general, analysis of duration may compare a measure of time until the endpoint across treatment groups. The appropriate method depends on the endpoint definition, measurement schedule, censoring, and other design details. Censoring occurs when the event time is not observed completely, for example if follow-up ends before the event occurs. The registry does not specify the endpoint unit, event definition, censoring rules, or an analysis method. No duration observations are reported, so none of these methods can be evaluated as actually applied.
A treatment-effect estimate would describe the observed difference or contrast between groups under the chosen analysis. A confidence interval would express uncertainty around that estimate, and a statistical test could assess compatibility with a null hypothesis under specified assumptions. These are general concepts; the registry reports no estimate, confidence interval, test statistic, or p-value for analgesia duration. No inferential conclusion can be drawn from an analysis that the record says was not done.
Why do analysis details matter?
Statistical interpretation depends on a clearly specified outcome, comparison, analysis population, and handling of missing observations. An analysis population defines which participants contribute to a particular estimate. For example, an intention-to-treat approach generally analyzes participants according to their randomized assignment, whereas other approaches may use different inclusion rules. The registry does not report an analysis population or the planned handling of deviations and missing data. Given the stated absence of outcome data, it also provides no realized population for a primary-outcome analysis.
In general, small studies can yield imprecise estimates, and estimates based on sparse observations may be sensitive to individual outcomes. That general caution is relevant to interpreting a record with listed enrollment of 5, but no outcome estimate exists to characterize its actual precision. The registry does not report a sample-size justification or statistical plan, so the intended power, target effect, model, and assumptions cannot be established from the record.
For outcomes that are counts or rates, over-dispersion can matter when observed variability exceeds what a statistical model assumes. For time-to-event outcomes, censoring and the timing of events can affect the analysis. These general considerations are not evidence that either issue occurred in this study. The record supplies no primary outcome data with which to assess them and does not report the relevant planned methods.
Any sample-size illustration based on an observed treatment effect would require an observed effect estimate. The registry says no outcome data were collected and no analysis was done, and the record does not present a primary effect estimate. Accordingly, no trial-specific effect-based planning conclusion can be drawn from the primary outcome record. Such planning calculations, when available, are illustrations for future designs rather than measures of the study’s observed power.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity concerns arise when a study tests several outcomes, time points, or treatment comparisons. In general, making many statistical tests can increase the chance of at least one apparently notable result even when there is no underlying effect. A prespecified primary outcome and comparison can help focus interpretation, while adjustment methods may be used when appropriate. The registry identifies Analgesia Duration as the primary outcome, but it does not report a statistical analysis or a multiplicity strategy.
The record lists one outcome measure and states that no analysis was done. It does not report whether secondary outcomes were planned, how the listed arms would be compared, or whether any interim analyses were planned. Those details are not reported in the registry record; no assumptions about them are warranted. Because no outcome results are reported, there are no trial findings for which multiplicity adjustment could be assessed.
Missing data and absent data are important to distinguish. The registry description says that the study was terminated prematurely due to lack of resources and participation, with no data collected for outcome measures. It does not describe a completed outcome dataset with some values missing. Nor does it specify imputation, exclusion, or sensitivity-analysis procedures. The effect of missing-data assumptions cannot be evaluated because the record contains no primary outcome observations or analysis.
The registry does not identify an analysis population, such as an intention-to-treat or per-protocol population. It also does not describe how protocol deviations, withdrawals, or incomplete follow-up would have been handled. These elements are not reported in the registry record. The posted record therefore supports neither a multiplicity-adjusted result nor an analysis of missing outcome data.
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 |
|---|---|---|---|
| Bupivacaine | 0 | 3 | 0.0% |
| Bupivacaine With Dexamethasone | 0 | 1 | 0.0% |
| Intravenous Dexamethasone | 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 |
|---|---|
| Bupivacaine | 0 of 3 |
| Bupivacaine With Dexamethasone | 0 of 1 |
| Intravenous Dexamethasone | 0 of 1 |
The registry lists serious adverse events and other adverse events by group. For bupivacaine, the serious-event count is 0 among 3 at risk, and the other-event count is 0 among 3 at risk. For bupivacaine with dexamethasone, the serious-event count is 0 among 1 at risk, and the other-event count is 0 among 1 at risk. For intravenous dexamethasone, the serious-event count is 0 among 1 at risk, and the other-event count is 0 among 1 at risk.
These are the figures posted in the registry and should be read alongside their group-specific at-risk counts. A zero affected count means no affected events are listed for that category in the posted summary; it does not establish that a treatment is risk-free. The groups have limited at-risk counts, and the registry does not provide additional detail about event collection or follow-up in this summary.
Deaths are marked as null for each group, not as a numerical zero. The registry also lists no top serious-event terms. Safety data do not answer the primary question about duration of analgesia, for which the registry reports no collected outcome data and no analysis.
12. What the Result Does, and Does Not, Mean
The record documents a randomized, quadruple-masked, parallel study intended to compare dexamethasone mixed with bupivacaine, intravenous dexamethasone, and bupivacaine control for analgesia duration. The primary outcome timeframe was 72 hrs. The registry states that the study was terminated prematurely because of lack of resources and participation, and that no outcome data were collected and no analysis was done.
What the record does show is the study’s stated question, its listed interventions, design labels, enrollment, status, and posted adverse-event summaries. It does not show whether analgesia lasted longer in any group, whether the local and intravenous approaches differed, or how large or precise any such difference might have been. No primary effect estimate or inferential result is reported.
This absence of results should not be interpreted as evidence of equivalence or as evidence of no effect. Establishing similarity generally requires an analysis designed to assess a prespecified margin of acceptable difference; such an analysis is not reported. Nor does the record establish benefit or harm on the primary endpoint. It simply lacks the collected outcome data needed to evaluate that question.
The posted adverse-event counts are descriptive entries with group-specific at-risk counts. They do not replace the missing efficacy outcome, and the null entries for deaths are not numerical zero counts. Any broader conclusion about the treatment approaches would go beyond what the registry record reports.
13. Why This Trial Matters Statistically
This trial is statistically instructive because a clear research question and a randomized design do not by themselves produce an interpretable treatment-effect estimate. The registry describes a comparison intended to distinguish a local dexamethasone effect from a systemic one, with bupivacaine alone as control. But the record also states that no outcome data were collected and no analysis was done. Without observed outcomes, statistical methods cannot quantify the contrast or its uncertainty.
The distinction between a planned comparison and a reported result is central to evidence interpretation. Randomization can help address confounding in a completed comparison, while masking can help limit measurement and behavior biases. Neither feature supplies missing outcome observations. The record’s termination status and stated reasons therefore matter when judging what the study contributes: it documents an intended design, not an estimate of treatment effect.
The record also illustrates why the endpoint definition and analysis plan matter. Duration of analgesia may require clear rules for identifying the endpoint and handling observations without a fully observed event time. The unit, operational definition, and planned analysis are not reported in the registry record. These omissions prevent a reader from reconstructing how a completed endpoint analysis would have been conducted, apart from the broad outcome title and timeframe.
Finally, the safety counts require restraint. Zero affected events are listed in the posted summaries, but the at-risk counts are limited and deaths are not expressed as numerical counts. These figures cannot settle the primary question and should not be converted into a general claim about safety. The record’s statistical value lies mainly in clarifying the gap between a planned randomized experiment and the unavailable outcome evidence.
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 explicit in the registry: the study was terminated prematurely because of lack of resources and participation, and no outcome data were collected for the outcome measures. No analysis was done. As a result, there is no primary endpoint estimate, no group-level comparison, and no reported measure of uncertainty.
Enrollment is listed as 5, but the record does not report the distribution of enrollment across the study arms for the primary outcome. The adverse-event summaries provide at-risk counts by group, but those figures should not be treated as a substitute for a participant flow or outcome analysis. The registry does not describe withdrawals, follow-up completion, or how many participants, if any, contributed to an endpoint assessment.
The endpoint is titled Analgesia Duration and has a 72 hrs timeframe, but its unit and detailed operational definition are not reported in the registry record. The record does not state how the end of analgesia would be determined, how incomplete follow-up would be handled, or what statistical model was planned. It also does not report the specific primary comparison or a statistical analysis plan.
The registry identifies randomization and quadruple masking but does not describe the allocation process or which roles were masked. A sample-size justification and planned analysis population are not reported. These design details are therefore not available for appraisal. The listed safety counts are limited summaries, and deaths are marked null. Together, these limitations mean the record supports a description of the intended study and its termination, but not an estimate of efficacy or a complete assessment of safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Dexamethasone and Block Duration in Upper Extremity — NCT01756573.
- Registry record last updated 2019-05-14; status last verified 2019-04.
- Results first posted 2019-05-14.
- 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
NCT01756573 is a randomized, quadruple-masked, parallel study sponsored by the University of Chicago. It lists bupivacaine control, bupivacaine with dexamethasone, and intravenous dexamethasone, with enrollment of 5. The registry gives a study start of 2013-01, a primary completion date of 2015-01, and a status of terminated.
The primary outcome is Analgesia Duration, with a timeframe of 72 hrs. The registry says the study was terminated prematurely because of lack of resources and participation, and that no outcome data were collected and no analysis was done. No primary treatment-effect estimate is reported. Adverse-event summaries list zero serious and other affected events in each group; deaths are marked null.