Hair Count Reduction Verification Study With the LightSheer Duet HS Handpiece: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Hair Count Reduction Verification Study With the LightSheer Duet HS Handpiece (NCT01282866), a na na study. The primary outcome is Hair Count.

2. Clinical Question

3. Trial Design

NCT01282866 is recorded as a completed study sponsored by Lumenis Be Ltd. Enrollment is listed as 35. The study start is recorded as 2009-06 and primary completion as 2011-11. The phase and allocation are listed as NA, masking as none, and the model as single-group. The intervention is the LightSheer Duet device, with the arm description specifying treatment with the HS handpiece. These details describe the registry design; they do not establish what treatment procedures each participant actually received or how adherence was assessed.

The stated objective was to verify hair count reduction and assess associated comfort or discomfort and treatment time using the LightSheer Duet System with HS handpieces. The summary anticipates that the larger HS handpiece treatment size may allow faster treatment of larger areas, and that lower energy levels may be associated with greater comfort. These are expectations expressed in the study objective, not findings. The registry record does not report comparative results for treatment time or comfort.

A single-group design describes observations in a treated group without a concurrent control group identified in the record. It can characterize recorded outcomes in that group, but by itself it cannot separate treatment-associated change from other explanations such as natural change, measurement variation, or differences in observation. Since allocation is NA and no comparator is reported, an effect relative to another treatment or to no treatment is not established by the design description. Details of randomization procedures, if any, are not reported in the registry record.

The registry lists four outcome measures and one analysis. It does not report the detailed protocol, the planned analysis population, or whether changes to the design occurred. The completed status indicates the registry's status entry; it does not supply endpoint results or establish that every planned measurement was available for analysis.

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

Reasons for not completing this period:

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.

Population: The power calculation proposed a sample of 35 participants to be sufficient to obtain qualitative assessment of hair removal, as well as the qualitative assessment of treatment time and pain experienced during treatment with the LightSheer Duet HS handpiece.

6. Primary Endpoint

The registry lists the primary outcome as Hair Count, measured over 6 month following last treatment.

The primary outcome is hair count, with the unit described as percentage of hair clearance. The assessment is scheduled for 6 month following last treatment. The record says hair is counted at baseline and at follow-up, and describes clearance as determined by the percentage of hair left at follow-up compared with the baseline hair number. Because the description uses both the term “hair clearance” and a definition based on hair left, readers should retain the registry's wording rather than infer a different calculation or direction of effect.

A count-based endpoint can represent the amount of hair observed in a specified treatment area at the defined assessment time. Expressing the outcome as a percentage is intended to relate the follow-up count to the baseline count, rather than reporting only a raw count. In general, using a baseline reference can help describe change over time, but it does not by itself create a control group or show what would have happened without treatment.

The registry record specifies a mean and standard deviation as the summary measure for this continuous outcome. However, it does not report the observed mean, standard deviation, sample size analyzed for the endpoint, or a confidence interval. Consequently, the endpoint's observed level, variability, and precision are not reported in the registry record. The outcome definition and timing are available, but the numerical evidence needed to characterize the result is not.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation starts with identifying what was measured, when it was measured, and which groups were compared. In this study, the primary endpoint is hair count, expressed as percentage of hair clearance, assessed at 6 month following last treatment. The record describes baseline and follow-up counts and names a single-group model. No comparison group is identified. These design details set important limits on what an analysis can establish, regardless of the statistical method used.

What does a mean describe?

A mean is a measure of the central level of a set of observations. For a continuous outcome, it gives a compact description of the values across the analyzed participants. A mean alone does not show whether participants had similar outcomes or whether observations were widely spread. The registry specifies a mean for the primary endpoint, but the observed mean is not reported in the registry record. The endpoint result therefore cannot be described numerically.

Why report a standard deviation?

A standard deviation describes the spread of observations around their mean. It helps distinguish a tightly clustered set of values from one with greater variability. It is not the same as the uncertainty in the estimated mean: the former describes variation among observations, while the latter also depends on how much information is available. Since the record does not report the endpoint standard deviation or the number analyzed, neither the observed variability nor the precision of the mean can be assessed.

What would a confidence interval add?

In general, a confidence interval is a range of values compatible with the data and a specified statistical procedure. It communicates uncertainty around an estimate rather than only presenting a central estimate. A narrow interval indicates greater precision under the assumptions of the method; a wide interval indicates greater uncertainty. The registry record does not report a confidence interval for the primary endpoint. It is therefore not possible to evaluate precision from an interval or to assess which values remain compatible with the observed data.

Why does the single-group structure matter?

A within-group outcome can describe what was recorded among participants receiving the intervention. A control comparison addresses a different question: how outcomes differ between groups that are comparable apart from the treatment contrast of interest. Here, no control group is identified in the registry record, and allocation is NA. A baseline measurement can provide a reference for follow-up, but it does not supply the concurrent counterfactual that a control group is intended to represent. General interpretation should therefore distinguish observed change from a causal treatment effect.

How should the endpoint wording be read?

The registry labels the primary outcome as hair count and gives the unit as percentage of hair clearance. Its description says clearance is determined by the percentage of hair left at follow-up compared with baseline. Those phrases may be read differently if the direction or formula is not fully specified. No additional calculation rule is reported in the registry record. Statistical interpretation should preserve the recorded definition and avoid assuming whether a larger reported value means more clearance or more remaining hair.

What do the planning assumptions mean?

The record's sample-size assumptions describe a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. These are assumptions for planning illustrations, not the trial's own design or a report of its observed power. The study itself is listed as single-group, so the assumed two-arm allocation does not describe its recorded design. A planning calculation asks what sample size might be needed under its chosen assumptions; it does not establish that a study had a particular probability of detecting an effect after data collection.

General sample-size planning depends on the outcome's variability, the effect regarded as important to detect, the statistical threshold, allocation, and analysis method. If those assumptions differ from a future study's actual design, its planning estimate may not apply. The record does not report the original study's sample-size justification, and no rationale for enrollment is stated. Any planning illustration should therefore be kept separate from an account of what this completed single-group study tested or found.

Why can over-dispersion matter?

In general, over-dispersion means that data vary more than a statistical model assumes. A model that understates variability can produce uncertainty estimates that are too small. Model choice should reflect the outcome's structure and observed variability. The primary endpoint is characterized as a continuous measure summarized by a mean and standard deviation, but the registry record does not give the analysis model or diagnostic information. No claim about over-dispersion or a correction for it can be made from the record.

The registry lists one analysis. It does not describe a test statistic, model specification, covariate adjustment, treatment of repeated measurements, or confidence-interval procedure. Those methods are not reported in the registry record. Without the outcome estimate and its analysis details, the statistical methods cannot be independently checked or reconstructed.

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("HS Treatment")
n   <- c(34)
m   <- c(54)
sp  <- c(24)
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  HS Treatment  34  54.000  24.000  45.626  62.374

11. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and one analysis. It identifies hair count as the primary outcome and lists treatment time, level of comfort associated with treatment, and hair count among the secondary outcomes. The record does not explain how the listed outcomes relate to the analysis count, whether additional analyses were conducted, or whether any adjustment was planned for examining multiple outcomes. A multiplicity strategy is not reported in the registry record.

In general, multiplicity matters when several outcomes or analyses are considered because repeated statistical testing can increase the chance of findings that appear noteworthy by chance. An analysis plan may identify a primary outcome, define how secondary outcomes will be interpreted, or adjust inference to account for multiple tests. These are general approaches; the record does not state that any particular approach was used. No conclusion about the handling of multiplicity can be drawn from the number of outcomes alone.

Missing-data methods are also not reported in the registry record. The entry does not state how many participants had a hair count available at baseline or at follow-up, whether any measurements were missing, or how unavailable measurements were handled. It does not identify an imputation method or a sensitivity analysis for missing observations. Enrollment of 35 does not establish how many observations contributed to the endpoint analysis.

The analysis population is not reported in the registry record. The record does not specify whether the primary analysis included everyone enrolled, only participants who received treatment, or a subset with complete measurements. These distinctions can affect interpretation, especially when follow-up data are unavailable. The available registry information is therefore insufficient to assess missingness, the analysis population, or the robustness of the reported outcome.

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 serious adverse event terms

Serious events with the highest arm-level rate: injured ankle (2.9%).

For the HS Treatment group, the registry lists 35 at risk for serious adverse events and 1 affected. It lists 35 at risk for other adverse events and 0 affected. The top serious adverse event term is “injured ankle,” with 2.9% shown. These figures should be read as registry entries for the group, not as a comparison between treatment and control groups, since no control group is identified.

The record does not report the circumstances, timing, severity details, or relationship to treatment for the injured ankle term. The listing alone does not establish that the event was caused by the device or treatment. The deaths field is null; the number of deaths is therefore not reported in the registry record. A null entry should not be converted into a statement that no deaths occurred.

Adverse-event counts are distinct from the primary hair-count outcome. The safety entries do not fill the gap in the missing numerical efficacy endpoint, and the endpoint description does not determine the meaning of an adverse event. The registry record also does not give a fuller narrative or additional context for interpreting the safety entries.

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

The record establishes that a completed single-group study was registered to evaluate hair count after treatment with the LightSheer Duet HS handpiece. It defines a primary endpoint based on hair counts at baseline and at 6 month following last treatment, and it records enrollment of 35. It also identifies treatment time and comfort as secondary outcomes and includes adverse-event entries for the HS Treatment group. These registry entries describe the study's scope and registry entries.

The record does not provide the numerical primary endpoint result. It therefore does not establish the average measured percentage of hair clearance, the variation among observations, or the precision of an estimate. The stated objective and anticipated effects on treatment time and comfort are not evidence that those expectations were met. Numerical results for the secondary outcomes are not reported in the registry record.

The single-group design also limits what can be inferred. A recorded change in a treated group, even if its value were available, would not by itself show how outcomes would have differed in the absence of treatment or under another intervention. No concurrent comparator is identified, and the registry does not report masking. This does not make the study's descriptive purpose meaningless, but it narrows the claims that can be supported.

The available information cannot establish which participants' measurements were analyzed, how missing observations were handled, or how the analysis was conducted. Those details are not reported in the registry record. The safety figures are likewise limited: they record affected counts and a serious-event term, but do not provide context establishing relatedness or circumstances.

Accordingly, the registry record supports a description of the planned question, design, endpoint timing, and selected safety entries. It does not support a numerical conclusion about the primary outcome, a comparative treatment effect, or a definitive interpretation of the anticipated benefits. Absence of a reported result should be understood as an information gap, not as a result in either direction.

14. Why This Trial Matters Statistically

This study illustrates why design and reporting need to be read together. A well-defined measurement time and a stated endpoint tell readers what investigators intended to assess. Here, the registry specifies hair count at baseline and at 6 month following last treatment, with the primary measure described as percentage of hair clearance. Yet without the numerical endpoint estimate and its variability, the stated measurement cannot answer how much change was observed or how precisely it was estimated.

The single-group design is also central to statistical interpretation. A baseline reference can describe change within participants, but a control group is needed for a direct comparison with an alternative course of events. Since the registry does not identify a comparator, the record cannot support a like-for-like comparative estimate. This distinction is important whenever an outcome is described as a reduction or improvement: a change over time and a treatment effect relative to a comparator are different statistical quantities.

The record further demonstrates that enrollment and analysis are not synonymous. Enrollment is reported as 35, while the analyzed endpoint population and missing-data handling are not reported in the registry record. Without that information, readers cannot determine how much endpoint information contributed to the estimate or whether missingness could affect interpretation.

Finally, registry objectives and anticipated outcomes should be separated from findings. The summary describes expectations about treatment time and comfort, but does not report their numerical results. Statistical reading depends on observed estimates, uncertainty, and design—not the anticipated direction of an outcome. The distinction helps prevent objectives, methods, and results from being treated as interchangeable evidence.

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.

Several limitations specific to this registry record constrain interpretation. The central limitation is the absence of a numerical primary endpoint result. Although the primary measure, summary form, and assessment time are described, the observed mean and standard deviation are not reported in the registry record. The record also provides no interval estimate, leaving the magnitude and precision of the outcome unknown.

The single-group design supplies no concurrent control comparison. Allocation is listed as NA and masking as none. The record therefore does not establish a comparative effect, and it gives no basis for assessing whether outcome assessment was protected from knowledge of treatment. Further details on how hair counts were obtained and whether assessors followed a specified measurement procedure are not reported in the registry record.

The endpoint description refers to percentage of hair clearance while defining the measure through the percentage of hair left relative to baseline. The exact calculation rule and direction of interpretation are not reported in the registry record. This wording limits clarity about how a numerical value should be interpreted, even if such a value were available.

Enrollment is reported as 35, but the number contributing data to the primary analysis is not reported. The handling of missing follow-up measurements, the analysis population, and any sensitivity analyses are also not reported in the registry record. The analysis methods beyond the listed mean and standard deviation are not described, and the original sample-size justification is not reported.

Finally, the record states expectations for treatment time and comfort but does not report numerical findings for those outcomes. The serious-event entry lacks contextual detail about circumstances and relatedness. These gaps mean that the registry record provides a limited account of both outcome evidence and safety context.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Hair Count Reduction Verification Study With the LightSheer Duet HS Handpiece — NCT01282866.
• Registry record last updated 2016-10-21; status last verified 2014-01.
• Results first posted 2014-04-03.
• 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

NCT01282866 is a completed, single-group study sponsored by Lumenis Be Ltd. It lists enrollment of 35 and treatment with the LightSheer Duet HS handpiece. The recorded study start is 2009-06, and primary completion is 2011-11. The primary outcome is hair count, described as percentage of hair clearance at 6 month following last treatment, with a mean and standard deviation specified as summary measures.

The registry record does not report the numerical primary endpoint result, its variability, or its precision. It identifies treatment time and comfort as secondary outcomes but does not report their numerical results. No comparator is identified. The record also does not describe the analysis population, missing-data handling, or detailed statistical analysis methods. Safety entries list 1 affected for serious adverse events and 0 affected for other adverse events in the HS Treatment group, with “injured ankle” listed among serious terms at 2.9%; the deaths field is null. These entries provide limited context and do not establish event relatedness.