A Treatment Regimen for Student Athletes With Mild to Moderate Acne Vulgaris: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Treatment Regimen for Student Athletes With Mild to Moderate Acne Vulgaris (NCT02249104), a na phase 4 study. The primary outcome is Mean Change From Baseline in Total Lesion Count.

2. Clinical Question

The study was intended to evaluate a complete topical acne regimen in student athletes. Its stated aims included safety, efficacy and patient satisfaction. The registry identifies mean change from baseline in total lesion count as the primary outcome, with the measurement timeframe listed as baseline and 8 weeks.

The question is descriptive for this study design: it concerns the change recorded within the group receiving the regimen. Because the record identifies a single group and no allocation to a comparator, it does not set up a randomized between-group estimate. The registry record does not report a numerical primary outcome result, so the size or precision of any lesion-count change cannot be assessed from the posted results.

The listed secondary outcomes concern percent or mean change in total, inflammatory and non-inflammatory lesion counts. The registry record does not report numerical analyses for those outcomes either. Thus, the stated research question can be identified, but the posted results do not show the endpoint estimates needed to quantify the observed changes.

3. Trial Design

This was a Phase 4, completed, single-group study sponsored by Galderma R&D. The registry lists enrollment of 28 and describes the condition as acne vulgaris. The study start is listed as 2014-08, and primary completion as 2015-02. The record identifies no allocation to different groups and no masking.

Participants were assigned to the listed Acne treatment group, which combined adapalene and benzoyl peroxide gel 0.1%/2.5% with a Cetaphil acne-care regimen. The gel was listed as once daily. The moisturizer with SPF 30 was listed as once daily, with an additional application described before outdoor sports under a stated timing condition. The foam wash appears in the regimen description, but its instructions are incomplete in the registry record.

With a single group and no masking, the design does not provide a concurrent control for separating changes during the study from other influences. The absence of masking also means that participants and study personnel were not described as blinded. These design features matter when interpreting changes in a clinical measure, but they do not tell us what change was observed.

The primary outcome was mean change from baseline in total lesion count, assessed at baseline and 8 weeks. The registry lists five secondary outcome measures involving total, inflammatory and non-inflammatory lesion counts. It records six outcome measures overall and zero analyses. No protocol details on sample-size justification, interim analyses or a fuller statistical plan are reported in the registry record. The tables, plots and planning section should therefore be read alongside this limited design description, rather than as a substitute for unavailable outcome estimates or protocol information.

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

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.

6. Primary Endpoint

The registry lists the primary outcome as Mean Change From Baseline in Total Lesion Count, measured over Baseline and 8 weeks.

Total lesion count is a count of the acne lesions assessed for each participant. The primary endpoint is the mean change from baseline in that count, with the registry specifying baseline and 8 weeks as the timeframe. A change score summarizes how participants' counts differed at the later assessment compared with their baseline measurement; the mean then summarizes those participant-level changes for the group.

This endpoint is used to describe change in a measured feature of acne over the study period. It is a continuous outcome in the registry's statistical classification, although the underlying observations are counts. The registry lists the measure in lesions counted and identifies standard deviation as the dispersion measure. A standard deviation describes how spread out participant-level measurements are around their mean; it is not the same as the uncertainty around the estimated group mean.

The record does not report the baseline or follow-up mean, the mean change, a standard deviation, or an interval estimate for the primary endpoint. It therefore does not permit assessment of the direction, magnitude or precision of the change. Nor does the endpoint, by itself, establish what would have happened to the same participants without the regimen. In a single-group study, the endpoint describes change over time in the group; it is not a controlled estimate of a treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the primary measure as continuous and names the summary parameter as a mean. It describes the dispersion as a standard deviation. Those labels describe how the outcome could be summarized; they do not supply the missing numerical estimate. The registry record lists no analyses, so no specific model, test, adjustment or estimation procedure can be established from the posted information.

What does a mean change summarize?

In general, a mean change is formed by considering each participant's change between the baseline and follow-up measurements, then summarizing those changes across the analysis group. A negative or positive direction depends on how the change is defined and displayed. The registry names the endpoint but does not state a numerical direction or value, so this page cannot characterize the observed change. A group mean also compresses individual results: participants can have different changes even when the average is close to zero.

The standard deviation describes variation among observations around their mean. It is useful for understanding how heterogeneous participant measurements may be. It does not, by itself, give the precision of the estimated mean. Precision also depends on how many participants contributed measurements and the analysis method. Although enrollment is listed as 28, the number analyzed for the primary endpoint is not reported in the registry record.

How would uncertainty be described?

In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the method used. It is not a range containing a fixed proportion of individual participant outcomes, nor is it a guarantee about the true value. The registry record does not report a confidence interval for the primary outcome. A p-value, if one had been reported, would address compatibility between data and a specified null model; it would not measure the size or importance of a change. No primary-outcome p-value is reported.

The outcome is a lesion count, so general statistical considerations for count data may be relevant. Count observations can be skewed, may include many small values, and may vary more than a simple model assumes. Over-dispersion means that observed variability exceeds what a particular count model expects. If present, it can make uncertainty estimates from an unsuitable model too small. These are general considerations, not claims about this study's data: the registry record does not report a distributional assessment or a count-data model.

What does the study design allow?

A single-group before-and-after analysis can describe change in the measured group over time. It does not provide the randomized contrast available when participants are assigned to a concurrent control group. General explanation: random allocation can help balance measured and unmeasured influences between groups on average, while a concurrent comparator can account for changes over time that are not unique to the intervention. Neither feature is listed for this study. This does not make a within-group description meaningless, but it limits causal interpretation.

The record lists masking as none. In general, knowledge of study participation or treatment can influence behavior, reporting, adherence and assessment. The extent of any such influence is not reported. The registry does not describe the lesion-count assessor, assessment procedures, or steps taken to standardize counts, so those details cannot be evaluated.

How should the planning calculations be read?

General explanation: a sample-size calculation estimates how many participants an imagined study would need under specified assumptions, such as a target effect, significance level, allocation plan and statistical model. It is a planning illustration, not a result from participants and not observed power. The stated planning framework uses a two-sided significance level of 0.05, equal allocation between two hypothetical arms, a normal approximation, and effects defined as stated fractions of an observed effect. For time-to-event outcomes, the stated convention is total events; for other outcomes, it is participants per arm.

Those assumptions describe the planning illustration, not this trial's design. This study had a single group, while the illustration assumes equal allocation between two arms. The registry record does not report a trial-specific sample-size justification or the numerical effect estimate needed to evaluate the planning assumptions. Any planning values should therefore be kept separate from the observed study evidence, and should not be interpreted as an estimate of what this trial demonstrated.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Acne Treatment")
n   <- c(28)
m   <- c(-26.9)
sp  <- c(25.3)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Acne Treatment  28  -26.900  25.300  -36.710  -17.090

11. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures: the primary mean change in total lesion count and secondary measures covering percent change in total lesion count, mean and percent change in inflammatory lesion count, and mean and percent change in non-inflammatory lesion count. It also records zero analyses. The list shows that several outcomes were contemplated, but it does not reveal which analyses were conducted or whether any multiplicity procedure was planned.

Multiplicity arises when several outcomes or statistical tests are considered. In general, the more opportunities there are to identify an apparently notable result, the greater the risk of a chance finding if each test is interpreted separately. Researchers may address this through a prespecified hierarchy, adjusted inference or clear designation of exploratory analyses. None of these approaches is described in the registry record, so the handling of multiplicity is not reported in the registry record.

The record does not report numerical outcome results, analysis populations, participant-level missingness, or methods for handling missing data. It is therefore not possible to determine whether all enrolled participants contributed to each measure, whether follow-up was complete, or whether an imputation or other missing-data method was used. General explanation: missingness can affect an estimate when the availability of observations is related to participant characteristics or outcomes; the direction and size of any effect depend on the data and assumptions.

The record also does not report whether analyses followed a prespecified protocol, whether exclusions were made, or how deviations from the regimen were handled. These details matter because outcome availability and analysis choices can influence how a result should be interpreted. Without posted analyses or a fuller statistical plan, the registry record does not allow assessment of these issues.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists 28 participants at risk for serious adverse events in the Acne Treatment group and reports zero affected by serious adverse events. This is a count for the study group in the registry; it does not, on its own, establish that a regimen is safe or exclude uncommon harms. The record lists no serious adverse-event terms.

For other adverse events, the registry lists 28 participants at risk and 18 affected. This figure indicates the number recorded as affected in the registry summary; it is not a description of the event types, severity, timing or duration. Those details are not reported in the registry record. The summary also does not give a comparison group, so the figures cannot establish how the event burden differs from what would have occurred without the regimen.

The deaths entry is null, so deaths are not reported in the registry record; it should not be read as a reported count of zero. More generally, adverse-event counts require context about definitions, collection methods and follow-up. The registry record does not provide those details in the registry record. These figures should therefore be read as a limited summary of recorded event counts, not as a complete characterization of safety.

13. What the Result Does, and Does Not, Mean

This record shows that a completed Phase 4 study enrolled 28 student athletes with mild to moderate acne vulgaris and evaluated a topical regimen in a single group. The primary outcome was mean change from baseline in total lesion count over baseline and 8 weeks. The registry also lists secondary lesion-count outcomes and summarizes adverse events. These details establish the study's topic and broad design.

The posted results do not include a numerical primary outcome analysis. The registry records zero analyses, so there is no reported mean change, uncertainty interval or test result on which to base a quantitative account of lesion-count change. The same limitation applies to the listed secondary outcomes. The study's aims include safety, efficacy and patient satisfaction, but the absence of numerical results means the record does not show the size or precision of changes on those outcomes.

Even with a reported change, the design would support a within-group description rather than a randomized comparison. A single-group study cannot separate the regimen's contribution from other influences on change over time. The absence of masking may also matter for behaviors or assessments, although the record does not report whether these affected the measurements.

The adverse-event summary records zero participants affected by serious adverse events among 28 at risk and 18 affected by other adverse events among 28 at risk. These counts are useful to report as they appear, but they do not reveal event types or provide a controlled comparison. The deaths entry is not reported in the registry record.

In short, the record allows a careful description of the intended question, regimen, design and limited event summary. It does not support a quantitative conclusion about the primary endpoint, a causal estimate, or a broad claim about efficacy or safety. Those judgments require outcome data and study details that are not reported in the registry record.

14. Why This Trial Matters Statistically

Statistically, this study is useful as an example of the distinction between a research question and the evidence needed to answer it. The registry clearly names a primary outcome and timeframe: mean change in total lesion count from baseline to 8 weeks. It also specifies a group size and several secondary measures. Yet the record lists zero analyses and no numerical endpoint results. Knowing what was measured is not the same as knowing what the measurements showed.

The design makes another important teaching point. A single-group before-and-after study can describe observed change, but it does not create a randomized comparison. That distinction matters when moving from “change was measured” to “the regimen caused the change.” The latter statement requires stronger comparative evidence than this design supplies.

The page also separates outcome summaries from planning calculations. Planning illustrations can help show how sample size depends on assumptions about an effect and a statistical procedure. They are not participant outcomes and cannot replace the study's own analysis. The stated planning framework assumes two-arm allocation even though this trial is single-group, making it especially important to keep the illustration distinct from the trial design.

Finally, the record demonstrates why safety summaries need careful wording. The listed serious and other adverse-event counts are not a complete account of event type, timing or comparison. Reporting the figures accurately, while acknowledging what is absent, is more informative than turning limited counts into a broad conclusion.

15. 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 direct limitation for interpreting the study is the absence of numerical analyses in the registry record. Although the primary and secondary outcomes are named, no means, standard deviations, confidence intervals or p-values are reported. The direction, magnitude and precision of any outcome change are therefore not available for evaluation.

The study had one group, no randomized allocation and no masking. There is no concurrent control against which to compare changes. Consequently, the design cannot isolate changes associated with the regimen from other time-related influences. The registry record does not report enough detail to assess how outcome assessments were conducted or whether the lack of masking influenced measurement.

Enrollment is listed as 28, but the number contributing to each outcome is not reported. The analysis population, follow-up completeness, missing-data handling and any exclusions are also not reported in the registry record. These omissions prevent assessment of how much information underlies a possible outcome estimate.

The regimen description is incomplete for the foam wash, ending before its full instructions are stated. The record also does not report a trial-specific sample-size justification, a detailed statistical plan, multiplicity handling or interim analyses. Participant characteristics beyond the stated population, and detailed adverse-event descriptions, are not available in the registry record.

These limitations concern what can be learned from the registry information; they do not establish that the unreported procedures or data were absent from the study itself. They mean that such details cannot be evaluated from the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Treatment Regimen for Student Athletes With Mild to Moderate Acne Vulgaris — NCT02249104.
• Registry record last updated 2022-08-23; status last verified 2016-04.
• Results first posted 2016-05-26.
• 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.

19. Record Summary

NCT02249104 is a completed Phase 4, single-group study sponsored by Galderma R&D. It enrolled 28 student athletes with mild to moderate acne vulgaris. The listed regimen combined adapalene and benzoyl peroxide gel 0.1%/2.5% with Cetaphil DermaControl moisturizer SPF 30 and foam wash. The study start is listed as 2014-08 and primary completion as 2015-02.

The primary outcome was mean change from baseline in total lesion count at baseline and 8 weeks. Five secondary lesion-count outcomes are also listed. The registry records six outcome measures and zero analyses, so numerical outcome results are not reported in the registry record.

The adverse-event summary lists zero participants affected by serious adverse events among 28 at risk and 18 affected by other adverse events among 28 at risk. Deaths are not reported in the registry record. The single-group design does not provide a randomized comparison.