Ultrasound Device for Hair Removal: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ultrasound Device for Hair Removal (NCT01057134), a na phase not stated study. The primary outcome is Reduction in Hair Count in the Treated Area.

2. Clinical Question

3. Trial Design

This was a completed, single-group device study sponsored by Cutera Inc. The registry record lists 10 enrolled participants and identifies the intervention as the Cutera Ultrasound Device, also named Cutera UHAIR. The stated study purpose was to evaluate safety and efficacy for hair removal. The treated sites were the arm, calf, and thigh.

The allocation field is listed as not applicable, and the masking field is listed as none. These entries are consistent with the record’s description of a single-group study rather than a randomized comparison. No like-for-like control arm is described. As a result, the study record does not provide a concurrent group for comparing hair-count changes under another treatment or under no treatment.

The record gives a study start of 2010-03, a primary completion date of 2011-03, and a completed status. The primary outcome timeframe is baseline and 3 months after the final treatment, with the timeframe also described as up to 28 weeks. The registry record does not report the treatment schedule, the exact number of treatments, or further details about how the treated areas were assessed.

The record identifies one outcome measure and zero analyses. It does not include a primary outcome estimate, standard deviation, or statistical test result. It also does not report a sample-size justification, an interim-analysis plan, or a statistical analysis plan. The study design therefore supports a description of the intended single-group assessment, but the registry record is insufficient to reconstruct how the endpoint was analyzed or to judge its observed precision.

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 Reduction in Hair Count in the Treated Area, measured over baseline and 3 months post final treatment (up to 28 weeks).

The primary endpoint is titled “Reduction in Hair Count in the Treated Area.” It is defined as percentage hair reduction 3 months after the final treatment compared with baseline in the treated areas. The record names the arm, calf, and thigh as treatment sites and specifies the measure as a mean with standard deviation.

Hair count is a direct measure related to the study’s stated hair-removal purpose. Expressing change as a percentage relative to baseline is one way to describe the amount of reduction in the measured areas rather than reporting only a raw count. This is a general explanation of the measure; the registry record does not provide the calculation details, measurement procedures, or the observed endpoint value.

The assessment time is important to interpretation. The endpoint refers to 3 months after the final treatment, and the record gives the broader timeframe as baseline and 3 months post final treatment, up to 28 weeks. This makes the endpoint a follow-up measure rather than an immediate assessment during treatment. The record does not state whether measurements were available for every participant or how any unavailable measurements were handled.

The intended summary is a mean, with standard deviation describing variability across observed measurements. However, neither the mean percentage reduction nor its standard deviation is reported in the registry record. Consequently, the endpoint definition can be described, but the observed amount of hair-count reduction and its variability cannot be interpreted.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is continuous: it is a percentage hair-reduction value summarized as a mean and standard deviation. The registry record identifies the endpoint but does not report its numerical summary or the analysis used. The following explanations describe general statistical concepts and should not be mistaken for methods documented for this study.

What does a mean describe?

For a continuous measure, the mean summarizes the central value of the observed measurements. In this study, the intended mean would describe percentage hair reduction across the measurements included in the analysis. A mean alone does not show whether individual observations were close together or widely dispersed, and it can be affected by unusually high or low observations. The record does not report the observed mean, so the direction and magnitude of the endpoint result cannot be characterized.

What does the standard deviation describe?

The standard deviation describes variability among observations around their mean. It is not the same as the uncertainty in the estimated mean. A large standard deviation can reflect substantial variation across participants or measurements, while a smaller standard deviation indicates observations more concentrated around the mean. These general interpretations depend on the actual data and measurement process. The registry record names standard deviation as the dispersion measure but does not report its value.

How would a confidence interval help?

In general, a confidence interval gives a range of values compatible with the data under the method used, and communicates uncertainty around an estimate. It is useful to consider both the estimate and its interval rather than relying on a test result alone. A narrow interval indicates greater precision than a wide interval, while neither interval width nor a statistical test by itself establishes the practical importance of an effect. No confidence interval for the primary endpoint is reported in the registry record.

What does the single-group structure imply?

General statistical interpretation separates a within-group change from a treatment comparison. A baseline measurement can be compared with a later measurement in the same group, but that comparison does not provide the same evidence as a concurrent control group. Without a separate group, change over time cannot be attributed uniquely to the device. The registry record identifies a single-group model and no like-for-like control comparison, so a randomized between-group treatment contrast is not available in this record.

What does a significance level mean?

In general, a significance level is a decision threshold specified for a statistical test before evaluating data. The sample-size assumptions in the record refer to a two-sided significance level of 0.05. A two-sided test considers departures in either direction from a null value. That planning assumption does not show that this study performed such a test; the registry record lists zero analyses and does not report a test result or analysis plan.

Why can over-dispersion matter?

General explanation: over-dispersion occurs when variability in data exceeds what a statistical model assumes. If a model underestimates variability, its uncertainty estimates can be too small and its conclusions too confident. The endpoint is described as a continuous measure with a standard deviation, but the registry record does not report a model, evidence of over-dispersion, or a method for addressing it. Therefore, no claim about over-dispersion in this study is warranted.

How should planning illustrations be read?

General explanation: a sample-size calculation estimates how many observations might be needed under specified assumptions; it does not establish what was actually observed or guarantee a particular result. The record describes planning illustrations based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also distinguishes participant-per-arm calculations from total-event calculations for time-to-event outcomes. These are planning assumptions, not the trial’s own design description. The study itself is listed as single-group, and the registry record does not report a sample-size justification or the observed primary endpoint effect on which such illustrations would rely.

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("Arms", "Calf", "Thigh")
n   <- c(9, 9, 9)
m   <- c(13.1, 10.7, 18.7)
sp  <- c(9.1, 9.9, 15.5)
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  Arms  9  13.100  9.100  6.105  20.095
CARM  Calf  9  10.700  9.900  3.090  18.310
CARM  Thigh  9  18.700  15.500  6.786  30.614

11. Multiplicity, Missing Data and Analysis Populations

The registry record identifies one outcome measure and zero analyses. It describes a primary endpoint, but does not report statistical tests, model specifications, or a multiplicity strategy. Multiplicity refers generally to the increased chance of a false-positive finding when many hypotheses or outcomes are tested. With no analyses reported, it is not possible to determine what testing was conducted or whether multiplicity adjustments were considered. The record does not report an analysis plan.

Missing-data handling is also not reported in the registry record. The record does not state whether any primary endpoint measurements were unavailable, the number included in the endpoint analysis, or how missing measurements were treated. General statistical methods for missing data can make different assumptions and may lead to different estimates. Without the relevant information, no judgment about the effect of missing data is possible.

The analysis population is not reported in the registry record. Although the enrollment is listed as 10, the record does not say whether the primary endpoint was assessed for all enrolled participants or define an analysis set. It does not describe exclusions, protocol deviations, or how participants with incomplete follow-up were handled.

These omissions do not establish that multiplicity, missing data, or analysis populations were mishandled. They mean that the registry record does not provide enough information to evaluate those aspects of the analysis. The absence of a reported endpoint result and analysis further limits assessment of statistical uncertainty and robustness.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry record lists safety counts for all study participants. It reports 0 serious adverse events among 10 participants at risk, 3 other adverse events among 10 participants at risk, and 0 deaths. The record does not list any top serious adverse-event terms.

These entries are counts within the categories recorded by the registry. “Serious” and “other” adverse events are separate categories in the record and should not be treated as interchangeable. The 0 serious events entry does not mean that no adverse events of any kind were recorded, since the record also lists 3 other events. Likewise, the death count is recorded separately.

Counts alone do not describe the nature, timing, duration, intensity, or relationship to treatment of individual events. The registry record does not report those details or identify the specific terms for the other adverse events. It is therefore not possible to characterize the events beyond the categories and counts recorded.

These figures are descriptive safety information from the registry record. They do not, on their own, permit a comparative safety assessment, because the study is single-group and no comparator is reported. They should not be interpreted as a complete account of risk beyond the recorded categories and follow-up information.

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

This record establishes that Cutera UHAIR was evaluated in a completed single-group study with hair-count reduction designated as the primary endpoint. The endpoint was defined as percentage hair reduction in treated areas at 3 months after the final treatment compared with baseline. The study sites were the arm, calf, and thigh, and the endpoint summary was intended to include a mean and standard deviation.

The record does not report the primary outcome estimate, its standard deviation, a confidence interval, or a statistical test. It therefore does not tell readers how much hair-count reduction was observed or how precisely it was estimated. An endpoint description is not a substitute for the result, and the study purpose alone cannot establish the size or direction of an observed effect.

The single-group design also limits what a change from baseline could establish. In general, a within-group change does not isolate an intervention effect as a comparison with a concurrent control might. The registry record does not describe a separate control group, so it does not support a randomized treatment contrast.

The safety entries record 0 serious adverse events, 3 other adverse events, and 0 deaths, with 10 participants at risk in each listed category. These counts give limited descriptive information; the record does not identify the other events or provide a detailed account of their characteristics.

The record does not report an analysis population, missing-data methods, or an analysis plan. These gaps prevent a full assessment of the endpoint analysis and its uncertainty. The appropriate reading is therefore narrow: the registry documents the study’s purpose, design, endpoint definition, and selected safety counts, while leaving the primary outcome result and many interpretive details unreported.

14. Why This Trial Matters Statistically

This study is statistically useful as an example of the distinction between a clearly defined endpoint and a reported endpoint result. The registry specifies a continuous primary measure, its comparison with baseline, the treated areas, and the follow-up timeframe. It also names a mean and standard deviation as the planned summary. Those details help readers understand what the study intended to measure.

At the same time, the outcome estimate and its variability are not reported in the registry record. Without them, readers cannot assess the magnitude of the observed change or its precision. The distinction is important: a detailed endpoint definition supports interpretation of a result if one is available, but does not itself provide evidence about the result.

The single-group structure makes the record a useful reminder that within-group change and comparative evidence answer different questions. A baseline measurement offers a reference for describing later measurements, but it is not a concurrent control group. Consequently, this record cannot provide a like-for-like contrast between the device and another approach.

The safety counts also illustrate why categories and event descriptions matter. The record separates serious adverse events, other adverse events, and deaths, yet gives few details about the events beyond counts. Interpreting safety requires attention to those distinctions and to the information that remains unreported.

Finally, the record contains planning assumptions for sample-size illustrations, but does not report its own sample-size justification or primary analysis. This makes it important to distinguish hypothetical planning calculations from observed evidence and from the study’s actual design. The record’s value is in documenting the study structure and endpoint, while also showing how missing result and methods information can constrain statistical interpretation.

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 main trial-specific limitation in the registry record is the absence of a reported primary outcome result. Although the endpoint is defined as percentage hair reduction at 3 months after the final treatment compared with baseline, the record does not provide the mean or standard deviation. It therefore cannot support an assessment of the observed change or its precision.

The study is identified as single-group, with allocation not applicable and no masking. No separate comparator is described. As a result, a change from baseline, if reported elsewhere, would not be a direct comparison against an untreated or alternative-treatment group. The record itself notes that the arms are not a like-for-like control comparison.

The registry record lists 10 enrolled participants but does not report the number with endpoint data or the analysis population. It does not describe missing outcome data, exclusions, or how incomplete follow-up was handled. These gaps make it difficult to assess the completeness and representativeness of any endpoint summary.

Measurement procedures are not described in detail. The record does not report how hair count was assessed, who performed the assessment, or how percentage reduction was calculated. It also does not provide further details about the treatment schedule. The endpoint timeframe is given as 3 months post final treatment, up to 28 weeks, but additional timing information is not reported.

The safety record is limited to counts by category. It does not describe the other adverse events or provide details on timing, severity, duration, or attribution. The record also does not report a statistical analysis plan, multiplicity approach, interim analyses, or sample-size justification. These are limits on what can be inferred from the registry record, not evidence that any particular method was or was not used.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Ultrasound Device for Hair Removal — NCT01057134.
• Registry record last updated 2023-09-25; status last verified 2023-09.
• Results first posted 2023-09-25.
• 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 describes a completed single-group study sponsored by Cutera Inc., with 10 participants enrolled. The study began in 2010-03 and reached primary completion in 2011-03. Its stated purpose was to evaluate the safety and efficacy of the Cutera UHAIR ultrasound device for hair removal.

The primary endpoint was percentage reduction in hair count in the treated areas at 3 months after the final treatment compared with baseline, with the timeframe described as up to 28 weeks. The intended summary was a mean and standard deviation. Treated areas were the arm, calf, and thigh.

The record lists 0 serious adverse events, 3 other adverse events, and 0 deaths among 10 participants at risk in each category. It lists one outcome measure and zero analyses. The registry record does not report the primary outcome estimate, its variability, or the analysis methods needed to assess its precision.