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 Effect of Steroid for the Postoperative Swelling After Orthognathic Surgery (NCT01431014), a randomized phase 4 study. The primary outcome is Effect of Perioperative Steroid for the Postoperative Swelling After Orthognathic Surgery.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01431014 |
| Phase | Phase 4 |
| Condition | Swelling |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 56 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Chang Gung Memorial Hospital |
| Results posted | Yes |
2. Clinical Question
The clinical question is whether facial swelling after orthognathic surgery differs between the two perioperative dexamethasone dose groups. The registry record identifies the groups as dexamethasone 5mg and dexamethasone 15mg, and describes facial swelling as the primary outcome.
Population
People undergoing orthognathic surgery. The registry record does not give further eligibility details or a more specific description of the primary outcome population.
Intervention
Dexamethasone 15mg, described as the high-dose group. The outcome description says steroid use is intended as a single dose.
Comparator
Dexamethasone 5mg, described as the low-dose group. The comparison is between the two dose groups, not between dexamethasone and no steroid.
Primary question
How does the measured degree of facial swelling compare between the two groups? The primary outcome is described as a mean continuous measure in ml, using 3-dimensional photogrammetry. A single numerical comparison is not reported in the registry record.
The record describes the study purpose as developing a steroid regimen protocol to minimize postoperative facial swelling. That stated purpose is not itself evidence of a difference between dose groups. To answer the comparative question, readers would need the group-level outcome values, a measure of uncertainty, and the analysis used to compare them. Those results are not reported in the registry record in a form that allows a single comparison to be interpreted.
3. Trial Design
The registry record describes a randomized, double-masked, parallel-group trial. Participants were assigned to dexamethasone 5mg or dexamethasone 15mg. The listed enrollment is 56. The record identifies the study as phase 4 and gives its status as completed. Chang Gung Memorial Hospital is named as the sponsor.
Random allocation is intended to make treatment groups comparable at the start of a trial, on average. It does not ensure that the groups will be identical in every characteristic, particularly in a trial of this size. Masking is intended to limit the influence of knowledge about assigned treatment on care, measurement, or assessment. The registry record identifies the study as double-masked but does not report who was masked or how masking was maintained.
The parallel design means participants are assigned to one dose group rather than receiving both doses in sequence. The registry record describes steroid use as a single dose. Further details about timing, route, or other treatment procedures are not reported in the registry record.
The record lists the study start as 2011-08 and primary completion as 2013-01. It describes facial swelling measured with 3-dimensional photogrammetry, with images taken before and after surgery. The primary outcome timeframe is listed as 1 year. The record does not provide a single group comparison for that outcome. It also does not report details of the randomization procedure, allocation concealment, the masking roles, or a protocol for handling deviations from assigned treatment.
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 | Dexamethasone"High-dose" | Dexamethasone"Low-dose" |
|---|---|---|
| STARTED | 34 | 34 |
| COMPLETED | 31 | 25 |
| NOT COMPLETED | 3 | 9 |
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 | Dexamethasone"High-dose" | Dexamethasone"Low-dose" | Total |
|---|---|---|---|---|
| Participants analysed | 31 | 25 | 56 | |
| Age, Categorical: <=18 years | Participants | 1 | 5 | 6 |
| Age, Categorical: Between 18 and 65 years | Participants | 30 | 20 | 50 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 23.16 (SD 4.19) | 20.92 (SD 4.79) | 22.16 (SD 4.6) |
| Sex: Female, Male: Female | Participants | 15 | 13 | 28 |
| Sex: Female, Male: Male | Participants | 16 | 12 | 28 |
| Region of Enrollment: Taiwan | participants | 31 | 25 | 56 |
6. Primary Endpoint
The registry lists the primary outcome as Effect of Perioperative Steroid for the Postoperative Swelling After Orthognathic Surgery, measured over 1 year.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | ml |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is described as facial swelling measured using 3-dimensional photogrammetry. Images are intended to be taken before and after surgery, with the degree of swelling measured and compared. The outcome unit is ml, and the summary measure is a mean with standard deviation. The listed timeframe is 1 year.
Three-dimensional imaging offers a way to quantify facial shape and change without radiation, as the registry description notes. A quantitative measure can support comparison between groups rather than relying only on a general description of swelling. The meaning of a mean depends on the measurement procedure and on which images and time points contribute to it; those operational details are not reported in the registry record beyond the imaging description and timeframe.
The endpoint description also mentions monitoring symptoms of wound infection, psychosis, and prolonged wound healing. These are described as safety concerns, not as the primary swelling measure. The registry record does not report the group means, standard deviations, or a single numerical treatment contrast for the primary endpoint. It says the primary outcome has several categories or time points and was not reduced to one comparison. Therefore, the endpoint’s intended measurement can be described, but the size and precision of a between-group difference cannot be assessed from the reported primary-outcome information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the intended comparison: facial swelling after orthognathic surgery in the dexamethasone 5mg and 15mg groups. It also gives the measurement approach, a mean continuous outcome in ml, and a timeframe of 1 year. However, the primary outcome information is not reduced to a single comparison, and the numerical group results and treatment contrast are not reported in the registry record. There is consequently no reported effect estimate or confidence interval to interpret.
A difference between group means would describe the observed contrast in the measured swelling outcome. A confidence interval would show the range of effect values compatible with the data under the analysis assumptions, and would help indicate the precision of that estimate. Neither a mean contrast nor its uncertainty is reported in the registry record. A p-value or other formal test result for the primary comparison is also not reported in the registry record. Without these quantities, the direction, magnitude, and precision of the primary outcome comparison cannot be judged.
The randomized design is relevant because random allocation can reduce systematic differences between groups at baseline. It does not replace reporting the outcome data, and randomization alone cannot show whether an observed contrast is precise. Double masking may help reduce some forms of measurement or assessment bias, but the record does not identify who was masked or describe how masking was maintained.
The listed enrollment is 56, but that number alone does not establish how much precision the primary comparison achieved. Precision depends on the outcome variability, the allocation and analysis, and the amount of missing outcome data, among other factors. Those details are not reported in the registry record. Nor does enrollment alone establish that the study was adequately powered for a particular effect.
The safety record reports zero serious adverse events and zero other adverse events in each dose group among the listed at-risk counts. Death counts are not reported in the registry record. These safety entries should be interpreted as registry counts, not as proof that no events could occur or that the two doses have identical safety profiles. The record does not provide event definitions, follow-up completeness, or further detail on ascertainment.
Overall, the posted information describes a randomized dose comparison and its intended measurement, but it does not report a single primary outcome comparison. No conclusion about the direction or size of a difference in facial swelling can be drawn from the primary outcome information available in the registry record.
9. Statistical Methods Explained
The registry record describes a randomized, double-masked, parallel-group study comparing dexamethasone 5mg with dexamethasone 15mg. It identifies the primary outcome as continuous, summarized by a mean and standard deviation, with facial swelling measured in ml. The statistical method used for the primary comparison is not reported in the registry record. The explanations below are general descriptions of these statistical ideas, not claims about analyses performed in this trial.
What does a mean describe?
For a continuous outcome, the mean represents the arithmetic average of the measured values in a group. Comparing group means is one way to describe how the average measured outcome differs between treatment groups. The mean alone does not show how much individual measurements vary, whether the data are skewed, or whether the group contrast is estimated precisely. The standard deviation describes the spread of individual measurements around the group mean; it is not the uncertainty of the estimated mean difference.
To interpret a trial comparison, readers generally need the group summaries and a between-group estimate with an uncertainty measure. A confidence interval is a range of values that, under the statistical model and its assumptions, is compatible with the observed data. A narrow interval indicates greater precision than a wide interval, though precision is not the same as clinical importance. The registry record does not report a single group contrast, confidence interval, or primary-outcome test result.
Why does randomization matter?
Random allocation aims to prevent assignment from depending on participants’ known or unknown characteristics. This supports a fair comparison of groups, especially when allocation is implemented and concealed appropriately. Randomization does not guarantee identical groups, and it does not correct problems caused by missing data, departures from assigned treatment, or selective reporting. The registry record says the study was randomized but does not describe the random sequence method or allocation concealment.
In a parallel-group design, each participant is assigned to one group. A comparison of group outcomes can then be used to estimate the difference associated with assignment, subject to the analysis choices and data quality. The record does not state whether the primary analysis followed assigned treatment, included only participants who completed treatment, or used another analysis population.
What does masking contribute?
Masking can reduce the chance that knowledge of assignment influences treatment decisions, participant reports, or outcome assessment. The value of masking depends on who is masked and whether the masking remains credible. The registry record labels the study double-masked, but does not specify the masked roles or provide details on how masking was protected. The outcome uses image-based measurement, but the record does not say whether image assessors were masked to group assignment.
Why can over-dispersion matter?
General statistical principle: over-dispersion occurs when observed variability is greater than a model assumes. If an analysis assumes less variability than is present, its uncertainty estimates can be too small, making results appear more precise than they are. For a continuous outcome, the standard deviation is one description of observed spread; appropriate uncertainty calculations also depend on the chosen model and the data structure. The registry record does not report a model, a dispersion assessment, or enough numerical outcome data to evaluate these issues.
What can be said about the planning illustration?
The record describes a planning illustration based on the observed effect. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set as a stated fraction of the observed effect. Such calculations illustrate sample sizes under assumptions; they are not observed power and do not establish the actual power of the completed trial. The numerical planning outputs and observed effect are not reported in the registry record, so no planning value can be interpreted.
The record does not report the test or model used for the primary outcome, adjustment for baseline measurements, treatment of repeated measurements, missing-data method, or primary analysis population. These choices matter because they determine how the estimate and its uncertainty are calculated. Without the group-level results and analysis details, the statistical evidence for the primary comparison cannot be assessed from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record says the primary outcome has several categories or time points and was not reduced to one comparison. It lists the primary timeframe as 1 year, but does not report the individual outcome values or identify a single contrast to interpret. The number and definitions of the categories or time points are not reported in the registry record.
Multiplicity is a general statistical issue that arises when several outcomes, time points, or comparisons are examined. The more analyses considered, the greater the chance that at least one may appear notable by chance if each is evaluated without accounting for the others. A prespecified primary comparison and an appropriate multiplicity strategy can help clarify which result is confirmatory. The registry record does not report a multiplicity plan, a hierarchy of outcomes, or whether any adjustment was used.
Missing data can also affect an estimate. If outcome measurements are unavailable, the amount and reasons for missingness, as well as the analytic approach, can influence both the result and its uncertainty. The registry record does not report missing primary-outcome data, reasons for missingness, or a method for handling it. It does not report the analysis population or whether all randomized participants were included in the primary analysis.
Details about interim analyses, stopping rules, and the statistical analysis plan are not reported in the registry record. Their absence from the record does not establish whether such procedures were or were not used. Without these details and a clearly defined primary contrast, readers cannot determine how multiplicity or missingness may have affected interpretation.
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 |
|---|---|---|---|
| Dexamethasone"Low-dose" | 0 | 25 | 0.0% |
| Dexamethasone"High-dose" | 0 | 31 | 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 |
|---|---|
| Dexamethasone"Low-dose" | 0 of 25 |
| Dexamethasone"High-dose" | 0 of 31 |
The registry record lists safety counts separately for the dexamethasone 5mg and 15mg groups. For serious adverse events, it reports zero events among 25 at risk in the 5mg group and zero among 31 at risk in the 15mg group. For other adverse events, it likewise reports zero among 25 at risk in the 5mg group and zero among 31 at risk in the 15mg group. The death entries are not reported in the registry record.
Zero recorded events means that no events are listed in these registry fields for the specified groups; it does not establish that the true risk is zero. Safety estimates based on few or no recorded events may be imprecise, and the counts do not by themselves show whether groups differ. The registry record does not provide event definitions, details of ascertainment, or information about the completeness of safety follow-up. It mentions monitoring for wound infection, psychosis, and prolonged wound healing, but does not give separate results for those symptoms. The reported counts should therefore be read as limited registry safety information rather than a complete assessment of possible harms.
12. What the Result Does, and Does Not, Mean
The record identifies a randomized comparison of dexamethasone 5mg and dexamethasone 15mg for postoperative facial swelling after orthognathic surgery. It describes a non-invasive measurement approach using 3-dimensional photogrammetry and a primary outcome expressed as a mean in ml. This gives readers the intended comparison and the general form of the measurement.
What the posted results do not establish is the size or direction of a difference between the dose groups. A single numerical primary outcome comparison, group means, standard deviations, and uncertainty estimates are not reported in the registry record. Accordingly, the statistical evidence and precision of the intended comparison cannot be assessed from the primary outcome information available.
The stated study purpose is to develop a steroid regimen protocol for minimizing postoperative facial swelling. A stated purpose is not a result. Likewise, the description that side effects are expected to be low is an expectation in the registry description, not a finding. The safety counts list zero serious and zero other adverse events in each group, but deaths are not reported in the registry record, and the safety entries do not establish that risk is absent.
The record’s planning assumptions are not a substitute for observed results. A planning illustration based on an observed effect is a hypothetical calculation under stated assumptions; it is not observed power and does not demonstrate that a treatment difference exists. Numerical illustration outputs are not reported in the registry record.
Thus, the trial design and outcome measurement can be described, but the central comparative question remains unanswered by the numerical primary outcome information in the registry record. The record does not support a conclusion about whether the measured swelling differed between doses, how large any difference was, or how precisely it was estimated.
13. Why This Trial Matters Statistically
This trial is statistically relevant because it frames a dose comparison in a randomized, double-masked, parallel-group design. Such a design can support a direct comparison between two assigned regimens, while masking may limit some influences on treatment and assessment. The primary outcome is also quantitative: facial swelling is intended to be measured from 3-dimensional images and summarized as a mean in ml.
These features make clear outcome reporting especially important. A reader needs the group-level measurements and a defined contrast to understand what the trial found. A mean difference without a measure of uncertainty can be difficult to judge; a confidence interval helps communicate precision. In this record, the primary outcome has several categories or time points and is not reduced to a single comparison, so the central estimate and its uncertainty are not available as one interpretable result.
The trial also illustrates why enrollment and design labels are not enough to evaluate evidence. The listed enrollment is 56, but enrollment alone does not show the precision of the swelling estimate or establish power for a particular effect. Outcome variability, missing measurements, the analysis population, and the statistical method all matter, and those details are not reported in the registry record.
The safety entries are another reminder to distinguish recorded counts from a complete safety conclusion. Zero listed events in the reported categories does not mean that the risk is zero, particularly without event definitions and follow-up details. The statistical value of this record is therefore mainly in documenting the intended comparison and highlighting which result and analysis details are needed for a full interpretation.
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 trial-specific limitation for interpretation is that the primary outcome is not reported as a single numerical comparison. The record identifies a mean continuous measure in ml and a 1 year timeframe, but does not report the group means, standard deviations, treatment contrast, confidence interval, or a primary-outcome test result. It notes that the primary outcome has several categories or time points and was not reduced to one comparison.
Important measurement details are also not reported in the registry record. Although the description refers to 3-dimensional photogrammetry and images before and after surgery, it does not specify the exact measurement procedure, the outcome values at each time point, or how the multiple categories or measurements were handled in the analysis. The record does not say whether image assessors were masked.
Further design and analysis information is not reported in the registry record, including eligibility criteria, random sequence generation, allocation concealment, who was masked, the primary analysis population, missing-data handling, the statistical model, and any multiplicity strategy. The record also does not report interim analyses or the statistical analysis plan. Their status cannot be inferred from their absence in the record.
The safety information is limited to the listed counts. Event definitions, ascertainment details, follow-up completeness, and death counts are not reported in the registry record. These gaps limit interpretation of both efficacy and safety; they do not, by themselves, establish that the trial was poorly conducted or that unreported events occurred.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effect of Steroid for the Postoperative Swelling After Orthognathic Surgery — NCT01431014.
- Registry record last updated 2014-03-21; status last verified 2011-09.
- Results first posted 2014-03-21.
- 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
NCT01431014 is a completed phase 4 randomized, double-masked, parallel-group trial sponsored by Chang Gung Memorial Hospital. The listed enrollment is 56. The study compares dexamethasone 5mg with dexamethasone 15mg for postoperative facial swelling after orthognathic surgery.
The primary outcome is described as a mean measure of facial swelling in ml, assessed using 3-dimensional photogrammetry, with a listed timeframe of 1 year. The registry record does not report a single numerical primary-outcome comparison or its precision. Safety entries list zero serious and zero other adverse events in each group; death counts are not reported in the registry record.