Clinical Evaluation of Fractional Radiofrequency for the Treatment Acne Scarring: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation of Fractional Radiofrequency for the Treatment Acne Scarring (NCT03821324), a na na study. The primary outcome is Acne Scar Improvement.

2. Clinical Question

This question is about the change observed among participants who received the device in this study. It is not a randomized comparison of the device against another treatment or against no treatment. Without a separate control group, a change from baseline cannot by itself distinguish the treatment's contribution from other influences on assessments over time.

The registry describes the study as evaluator-blind, while its masking entry is NONE. Those entries do not establish every detail of how evaluators were kept unaware of treatment timing or how photographs were presented. Further operational details are not reported in the registry record.

The primary assessment was scheduled for 12 weeks post-final treatment, described as approximately Week 20. The recorded endpoint is a mean change on the GAIS scale, whose values range from -3 Very Much Worse to +3 Very Much Improved. The registry does not report the mean change, its standard error, or participant-level results. Therefore, the clinical question is identifiable, but its numerical answer cannot be read from the registry record.

3. Trial Design

This was a prospective, single-centre study of fractional radiofrequency for acne scarring, sponsored by Venus Concept. The registry lists the study as completed. It records a start date of 2018-12-11, a primary completion date of 2019-10-03, and enrollment of 15. The phase is listed as NA.

The study is described as single-group, with allocation listed as NA and no separate control arm. The intervention is the Venus Viva device. According to the study description, participants would receive three treatments on both sides of the face, with 3-5 week intervals between each treatment, and be followed at 6 and 12 weeks after their last treatment. These are the registered study plans; details of adherence and the timing actually experienced by participants are not reported in the registry record.

The primary assessment was scheduled at 12 weeks post-final treatment, described as approximately Week 20. Evaluators were to assess photographs using the GAIS. The brief study description calls the study evaluator-blind, but the registry's masking entry is NONE. The record does not explain the relationship between these entries or give additional blinding procedures.

The analysis population described in the study summary includes subjects who receive at least one treatment. The registry does not report how many participants received treatment, completed follow-up, or contributed to the primary assessment. It lists 14 participants at risk for the reported safety categories, compared with planned enrollment of 15; the reason for this difference is not reported in the registry record.

This design can describe outcomes observed over time in the treated group. It does not create a like-for-like control comparison. No randomization, allocation between groups, or comparator treatment is reported. A sample-size justification and detailed statistical analysis plan are not reported in the registry record, so the study's planning rationale and prespecified analysis choices cannot be established from the registered 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.

6 Weeks After Treatment

12 Weeks After Treatment

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 Acne Scar Improvement, measured over 12 weeks post-final treatment (approximately Week 20).

The primary endpoint concerns change in acne scarring at 12 weeks after the final treatment, compared with baseline. Blinded evaluators were to assess photographs using the 7-point Global Aesthetic Improvement Scale (GAIS), ranging from -3 Very Much Worse to +3 Very Much Improved. The registry describes the endpoint as a mean and gives its unit as units on a scale.

A baseline-referenced measure is useful for describing how assessments at follow-up differ from participants' starting assessments. Photographic evaluation can provide a structured basis for assessing visible change, while evaluator blinding is intended to limit the influence of knowledge about treatment on ratings. The registry does not report the blinding procedures in detail, and its masking entry is NONE, so the exact safeguards cannot be determined from the record.

A mean summarizes the central tendency of the recorded scale values, but does not show how individual assessments were distributed. In general, a mean can conceal variation between participants or evaluators. The registry identifies standard error as the measure of dispersion, but does not provide the numerical mean or standard error for the primary outcome.

The scale's direction makes positive and negative values interpretable as improvement or worsening, respectively, at the level of GAIS ratings. The record does not report a threshold for a meaningful change or a separate responder definition. Without the endpoint estimate and its uncertainty, the magnitude and precision of the observed change cannot be judged from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measure reported as a mean, with the unit described as units on a scale. In general, a mean condenses multiple observations into a single central summary. It can make results easier to interpret, but by itself does not show the range or pattern of individual scores. The registry does not provide the mean result for this study.

What does the standard error describe?

Standard error describes the precision of an estimated mean. In general, it reflects how much an estimate would vary across repeated samples under a statistical model. It is not the same as the spread of individual participant ratings: a standard deviation describes variation among observations, while a standard error concerns the estimate of the mean. The registry names standard error as the dispersion measure for the primary outcome but does not report its value.

A confidence interval is a range calculated by a statistical procedure to express uncertainty around an estimate. In general, narrower intervals indicate greater precision under the assumptions used, while wider intervals indicate less precision. A confidence interval is not a guarantee that the true value lies within that particular interval. No confidence interval for the primary outcome is reported in the registry record, so its precision cannot be assessed from such an interval.

How should the GAIS scale be understood?

The GAIS runs from -3 Very Much Worse to +3 Very Much Improved. The study describes a mean change measured in units on this scale. Using a mean treats the recorded values numerically and offers a compact summary, but the mean does not disclose how many observations fell at each scale value. In general, a scale summary is more informative when interpreted alongside the distribution of ratings and the assessment procedures. Those participant-level distributions are not reported in the registry record.

The endpoint is described as change at follow-up compared with baseline. In a repeated-measures setting, change scores can be formed by comparing a participant's later measurement with that participant's earlier measurement. Such an approach accounts directly for the baseline reference in the endpoint description. The registry does not specify the exact calculation, the unit of analysis for repeated assessments, or the model used to estimate the mean change. Those analysis details are not reported in the registry record.

What does the single-group design imply?

In general, a study with a single treated group can estimate or describe what happened among the participants observed, depending on the analysis and available data. A baseline comparison does not have the same role as a control group followed over the same period. Without a concurrent comparator, changes may reflect the intervention, natural change over time, measurement variability, or other influences. The registry lists the design as single-group and does not identify a comparison arm.

A randomized comparison can help balance factors between groups, on average, through allocation. This study does not report random allocation and lists allocation as NA. Consequently, between-group treatment effects and comparisons with another intervention are not estimable from the design described in the record. No adjusted or unadjusted treatment-effect estimate is reported.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability exceeds what a statistical model assumes. If ignored, standard errors can be too small and uncertainty can be understated. This issue is especially relevant to outcomes whose variability may differ from a simple model's assumptions. It is not possible to assess over-dispersion for this primary endpoint from the registry record: no outcome distribution, model specification, or residual information is reported. It would be inappropriate to claim that over-dispersion occurred or that a particular correction was used.

Similarly, the registry does not state whether the analysis adjusted for baseline values, evaluator effects, repeated measurements, or other covariates. These are possible analytical choices in general, not documented procedures for this study. The registered endpoint and its planned assessment do not establish which statistical model was ultimately fitted.

How should planning calculations be interpreted?

In general, sample-size planning calculations ask how many participants might be needed to detect an assumed effect under specified assumptions. They are illustrations conditional on those assumptions, not evidence about an observed treatment effect, and not a substitute for the estimate and its uncertainty. The registry record does not report a sample-size justification or the assumptions used in the study's original design. Any planning illustration based on an observed effect should not be interpreted as observed power or as a result of this single-group study.

Interpretation also depends on whether the statistical analysis was prespecified, whether all intended outcomes were reported, and how missing observations were addressed. The registry lists four outcome measures and 0 analyses, but does not provide a detailed analysis plan or numerical primary result. The registry record therefore does not allow verification of the specific statistical methods used for the posted primary outcome.

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("12-weeks After Last Treatment")
n   <- c(9)
m   <- c(0.26)
sp  <- c(0.12)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
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  12-weeks After Last Treatment  9  0.260  0.360  -0.017  0.537

11. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures: the primary acne-scar improvement endpoint and secondary outcomes for subject satisfaction, pain on a visual analog scale, and treatment tolerability. It lists 0 analyses. Numerical results for these outcomes and a plan for handling multiple statistical tests are not reported in the registry record.

Multiplicity arises when several outcomes, comparisons, time points, or analyses are examined. In general, conducting many tests can increase the chance of observing a nominally unusual result by chance. Statistical plans may address this through a prespecified primary endpoint, a hierarchy of tests, or an adjustment to inference. The record identifies a primary endpoint but does not report a multiplicity procedure or explain how secondary outcomes were to be interpreted alongside it.

Missing-data methods are also not reported. The study summary says analysis would be performed on all subjects who receive at least one treatment, but it does not state how many participants received treatment, how many had primary endpoint assessments, or how missing follow-up measurements would be treated. It does not describe imputation, complete-case analysis, or sensitivity analyses. These approaches are general possibilities, not methods documented for this study.

The planned enrollment is 15, while the safety group lists 14 at risk. The reason for the difference is not reported in the registry record. The number contributing to the primary outcome may not be inferred from either figure. Without the analysis population and missing-data details, it is not possible to determine how fully the primary estimate represents enrolled participants or how sensitive it might be to incomplete follow-up.

12. Safety Results

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

Deaths

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 records 14 participants at risk in the intervention group. In the serious adverse event category, 0 were affected; the recorded number of deaths is also 0. The other adverse event category lists 3 affected among 14 at risk. These counts describe the registry entries and should not be mistaken for a comparison between treatments.

The terms, circumstances, and timing of the other adverse events are not reported in the registry record. The record also does not give details about event severity within that category, whether events were considered related to the device, or how events were collected. The serious adverse event terms list is empty, but that does not add details about the other adverse event category.

In general, a count of zero recorded serious adverse events means that none were recorded in the listed group and risk set. It does not establish that the possibility of such events is absent, particularly when the group is small. These figures are descriptive and do not establish comparative safety, causation, or the likelihood of an event in other populations. The registry does not report a separate control group for safety comparison.

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

The registry record establishes that a prospective, single-centre study of Venus Viva for acne scarring was completed, and that its stated primary endpoint was change from baseline on a photographic GAIS assessment at 12 weeks post-final treatment. It also records the planned treatment schedule, the evaluator-blind description, and adverse event counts. These details identify what the study set out to assess and what safety counts were entered.

The primary numerical result is not reported in the registry record. Without the mean change and its standard error, readers cannot determine the observed direction or size of the primary endpoint result, or how precisely it was estimated. The record also lacks a confidence interval and a p-value. No claim about statistical significance, precision, or the extent of observed improvement can be supported from the available outcome information.

Even if a within-group change estimate were available, this single-group design would describe change among treated participants rather than establish a comparison with an untreated or differently treated group. In general, changes over time can have several explanations, and a baseline reference alone does not separate them. The design does not support a randomized comparison because no comparator arm or random allocation is recorded.

The safety counts are likewise limited. The record reports 0 affected for serious adverse events and 0 deaths among 14 at risk, as well as 3 affected in the other adverse event category. These entries do not give event details or establish attribution. They cannot be used to compare safety against another treatment.

The study's completion status does not mean that every planned outcome, analysis, or participant follow-up result is available in the registry. The planned enrollment and reported safety risk set differ, and the record does not explain why. The primary analysis population and missing-data handling are also not reported. The responsible interpretation is therefore limited to the registered design and safety counts; the primary outcome's observed result remains unavailable in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why design and reporting details matter alongside an outcome's name. The registered primary endpoint is specific about the measure, the baseline reference, the evaluator approach, and the follow-up time. That specificity helps readers understand what was intended to be measured. Yet without a numerical estimate and uncertainty measure, the primary result cannot be quantified or evaluated for precision.

The single-group design also illustrates the distinction between describing change and estimating a comparative treatment effect. A before-and-after assessment can summarize what happened in the treated group, but the absence of a concurrent comparator limits causal interpretation. This is an important distinction when interpreting any study that relies on change from baseline without a control group.

The record's design entries show why registry fields should be read together. The study description calls the assessment evaluator-blind, while the masking entry is NONE. The difference is not explained, so readers should avoid assuming detailed procedures beyond the description itself. Clear reporting of masking methods would help assess how ratings may have been influenced.

Finally, the record highlights the value of complete reporting about analysis populations, missing data, multiplicity, and endpoint estimates. Enrollment is recorded as 15, while the safety group has 14 at risk; the reason is not stated. The record names standard error as the dispersion measure but does not provide the primary estimate or its standard error. Without those elements, the endpoint's statistical precision remains unknown. These are general reporting considerations, not evidence that any particular analysis was performed or omitted after study completion.

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 principal limitation for interpreting the primary endpoint is that its numerical result is not reported in the registry record. The mean change, standard error, and any confidence interval or p-value are absent. Without them, the magnitude and precision of the primary outcome cannot be evaluated.

The single-group design does not include a concurrent control group, and allocation is listed as NA. The study can describe outcomes in the treated group, but it does not provide a randomized comparison against another treatment or no treatment. A baseline comparison alone cannot isolate the contribution of the device from other influences on change over time.

The study description calls the evaluation evaluator-blind, whereas the registry masking entry is NONE. The record does not explain this difference or describe how blinding was implemented. Because the primary endpoint relies on evaluator ratings of photographs, the absence of procedural detail limits assessment of possible rating bias.

Although planned enrollment is 15, the safety group lists 14 at risk. The reason is not reported, and the number included in the primary analysis is not given. The registered summary describes an analysis population based on receiving at least one treatment, but does not report how many participants met that criterion or completed follow-up. Missing-data handling, the analysis model, multiplicity procedures, and a sample-size justification are not reported in the registry record.

The safety entries are limited to counts. The registry does not describe the other adverse events, their timing, severity, or attribution, and there is no separate group for comparison. These limitations constrain conclusions to the registered design and counts, rather than supporting broader claims about outcomes or safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Clinical Evaluation of Fractional Radiofrequency for the Treatment Acne Scarring — NCT03821324.
• Registry record last updated 2023-08-04; status last verified 2021-03.
• Results first posted 2023-08-04.
• 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

The registry record concerns NCT03821324, titled “Clinical Evaluation of Fractional Radiofrequency for the Treatment Acne Scarring.” Venus Concept is listed as sponsor. The study is marked completed, with a start date of 2018-12-11, a primary completion date of 2019-10-03, and enrollment of 15.

The study is prospective, single-centre, and single-group. It evaluates Venus Viva fractional radiofrequency for acne scarring. The described schedule is three treatments on both sides of the face, spaced 3-5 weeks apart, with follow-up at 6 and 12 weeks after the final treatment.

The primary endpoint is mean change in acne scarring at 12 weeks post-final treatment, described as approximately Week 20, assessed from photographs using the GAIS. Its numerical result is not reported in the registry record. Safety entries list 14 at risk, 0 affected in the serious adverse event category, 3 affected in the other adverse event category, and 0 deaths. The record does not report the primary analysis population or missing-data methods.