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 Pre-Shave Gel and Brush in Pseudofolliculitis Barbae (NCT03043534), a randomized na study. The primary outcome is Patient Global Severity Assessment- Mechanics of Shaving.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03043534 |
| Phase | NA |
| Condition | Pseudofolliculitis Barbae |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 29 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Wake Forest University Health Sciences |
| Results posted | Yes |
2. Clinical Question
Population
Men aged 20-60 with mild-to-moderate pseudofolliculitis barbae (PFB), assessed using the Investigator Global Assessment. The registry description planned to enroll 40 men; the recorded enrollment is 29.
Intervention
Pre-shave gel and a cleansing brush used before participants’ usual shaving routine. Participants were to continue using their normal razors and shaving products and shave at least 3 times weekly.
Comparator
Usual razors and shaving products without a change to the usual shaving routine. The control group was also expected to shave at least 3 times weekly.
Primary question
How did participants’ ratings of the mechanics of shaving change from baseline to 6 weeks, and how did those ratings compare between the gel-and-brush group and the control group?
The central comparison concerns a patient-reported score about the experience of shaving, rather than a single count of skin lesions. The assessment asks about smoothness, shaving stubborn hairs, irritation when shaving with or against the grain, and how comfortably the razor glides over the skin. The score ranges from 5 to 20, with lower scores indicating better shave mechanics.
The randomized parallel-group design is intended to compare the two assigned routines over the study period. The registry description specifies baseline and 6-week assessments. However, the primary-outcome values, changes over time, and between-group contrast are not reported in the registry record. The record therefore identifies the question and the measure, but does not establish what the observed difference was or how precisely it was estimated.
3. Trial Design
This was a completed randomized, parallel-group study of pre-shave gel and brush in males with pseudofolliculitis barbae. The registry lists the allocation as randomized and the model as parallel. It lists masking as single; the brief description calls the study investigator-blinded. Which parties other than the investigators, if any, were masked is not reported in the registry record.
The brief description planned 40 men aged 20-60 with mild-to-moderate PFB, divided into a control group of 20 and an experimental group of 20. The recorded enrollment is 29. The record does not explain the difference between the planned group totals and the recorded enrollment, nor does it give the number assigned to each arm for the primary outcome analysis. The safety summaries list 15 participants at risk in the gel-and-brush group and 14 in the control group.
Both groups were to keep using their normal razors and shaving products during the six-week study. The experimental group also received pre-shave gel and a brush to use before the usual shaving routine. Participants in both groups were expected to shave at least 3 times weekly. The control group was not asked to change its usual shaving routine.
The primary outcome was the Patient Global Severity Assessment- Mechanics of Shaving, measured at baseline and 6 weeks. Secondary outcomes listed in the record include itching, burning and stinging; a quality-of-life survey; lesions; and the Investigator Global Assessment. The registry lists 5 outcome measures and 0 analyses. The phase is recorded as NA, and the study status is completed. The start date is 2015-11-12 and the primary completion date is 2016-10-12. Further details about allocation procedures, adherence, and the analysis population are not reported 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 | Gel and Brush | Control |
|---|---|---|
| STARTED | 15 | 14 |
| COMPLETED | 15 | 14 |
| 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.
| Characteristic | Unit | Gel and Brush | Control | Total |
|---|---|---|---|---|
| Participants analysed | 15 | 14 | 29 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 15 | 14 | 29 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 15 | 14 | 29 |
| Region of Enrollment: United States | Participants | 15 | 14 | 29 |
6. Primary Endpoint
The registry lists the primary outcome as Patient Global Severity Assessment- Mechanics of Shaving, measured over Baseline, 6 weeks.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the Patient Global Severity Assessment- Mechanics of Shaving. It is a patient rating of how easy or difficult several aspects of shaving are. Participants rate getting a smooth shave, shaving stubborn hairs, shaving against the grain with little irritation, shaving with the grain with little irritation, and moving the razor comfortably over the skin. Each item uses a scale from 1 to 4, where 1 means very easy and 4 means very difficult.
The five item ratings are totaled into a score from 5 to 20. Lower numbers indicate better shave mechanics. The scale therefore represents the participant’s overall reported experience across several shaving tasks; it is not a direct measure of lesion counts or an investigator’s assessment. The registry specifies a mean and standard deviation and gives baseline and 6 weeks as the timeframe.
This measure is relevant to the study question because the intervention is used before shaving and is intended to be evaluated in the context of the shaving routine. A patient rating can capture perceived ease and irritation across activities that may not be represented by a single clinical sign. At the same time, interpretation depends on knowing how the component ratings and total score changed, and how the groups compared. Those outcome values and inferential results are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a randomized comparison but does not report the primary endpoint results. It gives no group means, standard deviations, changes from baseline, between-group estimate, confidence interval, or p-value for mechanics of shaving. Consequently, the direction and size of any observed difference, and the precision of that difference, cannot be assessed from the registry information.
The endpoint is defined so that lower scores indicate better shave mechanics. That direction is useful for understanding a reported estimate, but it does not substitute for the estimate itself. Without outcome values, it is not possible to tell whether either group’s score changed between baseline and 6 weeks, whether the groups differed at follow-up, or whether any apparent change was large or small relative to the variability among participants.
The recorded enrollment is 29, while the brief description planned 40 participants. Safety summaries report 15 participants at risk in the gel-and-brush group and 14 in the control group. These safety denominators do not establish how many participants contributed data to the primary outcome at each time point. The analysis population and outcome-specific denominators are not reported in the registry record.
The record lists 5 outcome measures and 0 analyses. It also indicates that the primary outcome has several categories or time points and was not reduced to one comparison. Therefore, there is no single posted primary comparison from which to draw an inferential conclusion. No confidence interval is available to show the range of effect sizes compatible with the data, and no test result is available to indicate how the observed data compare with a null hypothesis under a specified analysis.
The registry describes an intended study and its measures, not evidence that can be used to quantify an intervention effect. The randomized allocation would be relevant to interpreting a reported between-group comparison, but allocation alone does not reveal the outcome. Any numerical effect, statistical significance, or practical importance is not reported in the registry record. Interpretation should remain limited to the design, endpoint definition, enrollment, and adverse-event counts that are recorded.
9. Statistical Methods Explained
The registry identifies a continuous primary measure summarized as a mean and standard deviation. General explanation: a mean describes the average score in a group, while a standard deviation describes how spread out individual scores are around that average. For a patient-rated score, the mean can provide a compact group summary, but it does not show every participant’s response or the shape of the score distribution.
What would a between-group estimate represent?
General explanation: in a randomized parallel-group study, a between-group estimate compares outcomes for participants assigned to the different routines. The estimate might concern scores at follow-up or changes from baseline, depending on the analysis plan. Those approaches answer related but distinct questions. A follow-up comparison describes how the groups’ scores differ at that time; a change comparison describes how much each group’s score moved from baseline. The registry record does not state which approach was used.
A confidence interval, if reported, would convey the precision of an estimated contrast by giving a range of values compatible with the data and the model’s assumptions. A narrow interval would indicate greater precision than a wide interval. The registry record does not report a confidence interval or a point estimate for the primary outcome, so neither the magnitude nor the precision of an effect can be evaluated.
How should a p-value be understood?
General explanation: a p-value describes how unusual the observed data, or data more extreme, would be under a specified null hypothesis and statistical model. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. A p-value also cannot establish that a finding is reliable when important aspects of the analysis or missing data are unknown. No primary-outcome p-value is reported in the registry record.
The registry lists 0 analyses, and the primary outcome is not reduced to one comparison because it has several categories or time points. This means the registry information does not identify one reported test or contrast as the primary inferential result. The record does not describe model covariates, a baseline adjustment, the handling of repeated measurements, or how component ratings were combined beyond specifying the total score. These details are not reported in the registry record.
What do the planning assumptions mean?
The sample-size assumptions describe a planning illustration based on the observed effect, not the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. Such calculations illustrate the number of participants per arm for a chosen power target under the stated assumptions. They are not observed power and do not show what the trial achieved. The registry record does not report the trial’s own sample-size justification or the observed effect needed to evaluate such an illustration.
General explanation: planning calculations depend on assumptions about the effect of interest, variability, significance threshold, allocation, and analysis. If those assumptions differ from the eventual study data or intended analysis, the calculated sample size may not describe the study’s actual operating characteristics. A planning result is not a substitute for an estimated effect with an uncertainty interval. No recalculated result or discrepancy is described in the registry record.
Why can variability matter?
General explanation: the standard deviation helps describe variability in a continuous outcome. Greater variability can make group differences harder to estimate precisely, while lower variability can allow more precision for the same amount of information. The score is bounded from 5 to 20, so its possible values are constrained; the registry record does not give a distribution or summary values that would permit assessment of whether the outcome was concentrated near one part of the scale.
General explanation: over-dispersion is a concern when observed variability exceeds what a chosen statistical model assumes. It can affect standard errors and uncertainty estimates, particularly when a model is built around a variance assumption. The registry record does not state that over-dispersion was assessed, and it does not provide enough outcome data to assess it independently. No particular model or variance correction should be inferred.
The stated endpoint and design make clear what kind of comparison would be of interest, but not how the investigators analyzed the collected data. The registry record does not report the test, model, assumptions, missing-data method, or a numerical primary result. Without these details and the outcome estimates, the statistical evidence cannot be reconstructed from the registry information.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 5 outcome measures: the primary mechanics-of-shaving score and secondary assessments covering itching, burning and stinging, quality of life, lesions, and the Investigator Global Assessment. Assessing several outcomes or time points can create multiplicity: when many comparisons are considered, the chance of finding a result that appears unusual by chance can increase. General explanation: a prespecified testing strategy or adjustment can help control the interpretation of multiple tests. The strategy used for this study is not reported in the registry record.
The registry indicates that the primary outcome has several categories or time points and is not reduced to one comparison. It records 0 analyses. Thus no analysis hierarchy, adjustment method, or single primary contrast is reported. The record does not identify whether baseline and follow-up values were analyzed together, whether changes were tested, or how secondary outcomes were handled in relation to the primary endpoint.
Missing-data handling and analysis populations are also not reported in the registry record. The enrollment is 29, and safety summaries list 15 participants at risk in the gel-and-brush group and 14 in the control group, but these figures do not show how many had usable primary outcome data at each assessment. The record does not state whether all randomized participants were included in an analysis, whether participants were analyzed according to assignment, or how any missing scores were treated.
General explanation: incomplete outcome data can affect estimates if the participants with observed scores differ systematically from those without scores. The direction and size of any such effect depend on why data are missing and on the analytic approach. Because the registry record does not describe missingness or its handling, that aspect of the result cannot be evaluated.
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 |
|---|---|---|---|
| Gel and Brush | 0 | 15 | 0.0% |
| Control | 0 | 14 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Gel and Brush | 0 of 15 |
| Control | 0 of 14 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Gel and Brush | 0 of 15 |
| Control | 0 of 14 |
The registry safety summaries list 15 participants at risk in the gel-and-brush group and 14 in the control group. The recorded serious adverse events are 0 in each group, other adverse events are 0 in each group, and deaths are 0 in each group. These counts describe the events recorded in the registry safety summaries for the stated participants at risk.
A zero count in a summary means no event of that category was recorded in that group’s reported safety figures. It does not establish that an intervention is free of risk or that no symptoms occurred outside the categories or collection procedures represented in the record. The registry record does not provide event definitions, the observation period for safety reporting, details of how events were collected, or information about events that did not meet the recorded categories.
The safety denominators are not the planned group totals of 20 and 20 described in the brief summary, and the record does not explain the difference. These safety counts should not be taken as the outcome-analysis denominators. They also do not give information about the size or frequency of less serious symptoms beyond the zero counts in the posted summary. The counts are descriptive and do not establish a comparative safety effect.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized parallel-group study was conducted to assess pre-shave gel and brush alongside usual shaving products in men with PFB. It defines a patient-reported primary measure, explains the direction of its score, and gives baseline and 6 weeks as the assessment timeframe. It also records enrollment and summary safety counts.
The record does not report the primary endpoint values or a statistical comparison. It therefore does not show whether scores improved, worsened, or remained similar, either within a group or between groups. There is no reported effect estimate or confidence interval with which to assess the magnitude and precision of a difference, and no p-value to describe a test against a null hypothesis.
This absence of outcome results should not be interpreted as evidence of no effect. It also should not be interpreted as evidence of an effect. The direction and size of any observed result are simply not reported in the registry record. The completed status indicates that the study is recorded as completed, but completion by itself does not reveal its findings.
The primary measure captures participants’ ratings of several parts of shaving, not a general measure of every aspect of PFB. Secondary outcomes include patient ratings of itching, burning and stinging, quality of life, lesions, and investigator assessment, but their results are not reported in the registry record. No conclusions about those outcomes can be drawn from their names alone.
Likewise, zero adverse-event counts in the posted safety summaries describe only the recorded categories and denominators. They do not establish the absence of all possible harms or provide a precise comparison between groups. The available record is informative about the planned comparison and outcome definitions, but it does not supply the efficacy or safety estimates needed to characterize the observed results.
13. Why This Trial Matters Statistically
This trial is statistically notable as a small randomized study with a patient-reported continuous outcome measured at baseline and follow-up. Its design distinguishes an added pre-shave routine from continued usual shaving, while asking participants about ease and irritation across several specific shaving tasks. That makes the outcome definition central to understanding what the study intended to measure.
The score combines several item ratings into a total from 5 to 20, with lower values indicating better shave mechanics. A total score can summarize a multi-part experience, but interpretation depends on the observed group values, variability, and between-group estimate. Those quantities are not reported in the registry record. The record therefore illustrates why a clear endpoint definition is not enough to evaluate an intervention effect: numerical results and their uncertainty are also needed.
The planned enrollment in the brief description differs from the recorded enrollment, and the safety denominators are 15 and 14. The registry does not explain the enrollment difference or give primary-outcome denominators. This distinction matters because study size and outcome completeness affect how much information a comparison contains, but the recorded totals alone do not establish the precision of an outcome estimate.
The registry lists several outcomes and time points but no analyses, and it does not reduce the primary outcome to one comparison. This highlights the importance of knowing which contrast was designated as primary and how multiple outcomes were handled. Without that information or a reported result, statistical significance, effect size, and precision cannot be judged.
The record is therefore useful for defining the research question and locating gaps in the results record. It does not provide enough statistical evidence to characterize the observed effect or its uncertainty.
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.
A central limitation of the registry information is the absence of numerical results for the primary endpoint. No group means, standard deviations, changes, between-group estimate, confidence interval, or p-value are reported. The primary outcome is also described as having several categories or time points and is not reduced to one comparison, so a single inferential result cannot be identified.
The brief description planned 40 men, with 20 in each group, while the recorded enrollment is 29. The registry record does not explain this difference. Safety summaries give 15 participants at risk in the gel-and-brush group and 14 in the control group, but the number contributing primary outcome data is not reported. The amount and pattern of missing outcome data are also not reported in the registry record.
Although the study is described as investigator-blinded and the registry lists single masking, the identity of any other masked parties is not reported. Details of the randomization procedure, adherence to the assigned routine, departures from the protocol, and analysis populations are not reported in the registry record. These factors can matter when interpreting a randomized comparison.
The record does not report how the primary score was analyzed, how the several outcome categories and time points were handled, or whether multiplicity was addressed. It does not give the study’s own sample-size justification. The planning assumptions describe an illustration based on an observed effect, but the observed primary effect is not reported. As a result, neither the intended precision nor the result’s statistical robustness can be evaluated from the registry record.
The safety data are limited to the recorded event counts and denominators. Event definitions, collection procedures, and timing are not reported. These limitations constrain interpretation of both benefit-related outcomes and safety, without implying that unreported information was absent from the study itself.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pre-Shave Gel and Brush in Pseudofolliculitis Barbae — NCT03043534.
- Registry record last updated 2018-12-19; status last verified 2018-11.
- Results first posted 2017-07-02.
- 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
NCT03043534 is a completed randomized, single-masked, parallel-group study of pre-shave gel and brush in males with pseudofolliculitis barbae. It compares adding gel and a cleansing brush before the usual shaving routine with continued use of usual razors and shaving products. The registry records enrollment of 29 and a brief description that planned 40 men aged 20-60.
The primary measure is a patient-rated mechanics-of-shaving score from 5 to 20, with lower scores indicating better mechanics, assessed at baseline and 6 weeks. The record lists 5 outcome measures and 0 analyses. Primary outcome results and analysis details are not reported in the registry record. Safety summaries list 0 serious adverse events, 0 other adverse events, and 0 deaths among 15 participants at risk in the gel-and-brush group and 14 in the control group.