Treatment of Androgenetic Alopecia in Females, 9 Beam: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Treatment of Androgenetic Alopecia in Females, 9 Beam (NCT00981461), a randomized na study. The primary outcome is Changes in Terminal Hair Count Week 16 and 26 Weeks Over Baseline.

2. Clinical Question

The clinical question is framed around a continuous measure: terminal hair count per unit of scalp area. Comparing change at two follow-up times can describe whether the groups' measured hair counts separated at either assessment. The registry record identifies baseline, Week 16, and Week 26 as the measurement time points, but supplies no group means, changes, uncertainty estimates, or test results. Consequently, the direction and size of any difference cannot be determined from the record.

The study is described as randomized, quadruple-masked, and parallel-group. These design labels indicate the intended comparison structure, but do not by themselves establish that allocation was concealed, masking was maintained, or all randomized participants contributed data. Those implementation and analysis details are not reported in the registry record.

3. Trial Design

The registry describes a randomized, double-blind clinical trial with quadruple masking and a parallel-group model. It compares the HairMax LaserComb 2009 9 Beam device with a control device in females diagnosed with androgenetic alopecia. The stated purpose is to evaluate efficacy in promoting hair growth when the device is used as directed. The record lists an enrollment of 72 and a completed status. It gives the study start as 2009-10 and primary completion as 2010-10.

Randomization is intended to create groups that are comparable, on average, with respect to measured and unmeasured characteristics. In a parallel-group design, each participant is assigned to a group and the groups are compared over the study period. Masking is intended to reduce the influence of expectations or knowledge of assignment on participant experience, care, outcome assessment, or analysis. The record's quadruple-masked designation does not identify which roles were masked or describe how masking was maintained; those details are not reported in the registry record.

The intervention and control are both identified as devices, but the record provides no further description of the control device. It also does not report the allocation ratio, sequence-generation procedure, allocation concealment process, treatment duration, adherence, or permitted concomitant treatments. These omissions limit how fully the conduct of the comparison can be evaluated.

The primary outcome description specifies assessment at baseline, Week 16, and Week 26. Its planned analysis separately models terminal hair count at Week 16 and Week 26. The record does not give the number of participants assigned to each arm in the main trial description, nor does it report the numbers included in either endpoint analysis. The safety record lists its own at-risk counts, but their relationship to enrollment, assignment, treatment, and outcome analysis is not reported in the registry record.

The trial is listed with phase NA. The registry record does not report a sample-size justification or explain how its enrollment target was selected. It also does not report a protocol document or details of any changes to the planned design.

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.

Before assignment: Key exclusion criteria was pregnancy, malignancy in target area, an no hair transplants, scalp reductions, or hair weaves. Active hair loss less than 12 months.

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.

6. Primary Endpoint

The registry lists the primary outcome as Changes in Terminal Hair Count Week 16 and 26 Weeks Over Baseline, measured over Baseline, 16 weeks, 26 weeks.

The primary endpoint is the change in terminal hair count from baseline, measured in hairs per cm^2, with assessments at Week 16 and Week 26. Terminal hair count is a continuous measure: it records a quantity rather than assigning each participant to a simple yes-or-no outcome category. A count expressed per area allows measurements to be considered in relation to the scalp area assessed.

Change from baseline focuses the comparison on how the measure differs from its starting value. In a randomized trial, comparing groups' follow-up values while accounting for baseline-related factors can help describe the treatment-group contrast, although the precise approach used is the separately modeled follow-up value rather than a stated change-score model. The registry record calls the endpoint “Changes in Terminal Hair Count Week 16 and 26 Weeks Over Baseline,” while its analysis description says terminal hair count at each follow-up is modeled as a function of treatment group and listed covariates.

The record specifies the mean as the measure of central tendency and standard deviation as the measure of dispersion. A mean describes the average count; a standard deviation describes how spread out individual measurements are around that average. The registry record does not report the group means, standard deviations, baseline values, adjusted estimates, or confidence intervals. It therefore does not establish the observed magnitude or precision of any group contrast. The endpoint is relevant to the stated hair-growth question, but a numerical result is needed to judge what the trial observed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary analysis is described as an analysis of covariance, or ANCOVA. In general, ANCOVA models a continuous outcome using a group indicator and other selected variables. It can estimate a group contrast while adjusting for differences in those variables. Here, the registry says terminal hair count at Week 16 and at Week 26 was modeled separately, with treatment group, study center, age, and Fitzpatrick Skin Type classification included in the model. Age was treated as continuous, while skin type was treated as a categorical variable with four levels.

What does adjustment mean?

General explanation: adjustment uses a statistical model to account for specified characteristics when estimating the contrast between groups. A continuous covariate contributes information according to its measured value; a categorical covariate represents membership in a category. Study center can account for differences associated with the location of assessment, while age and skin type are included as stated characteristics. Adjustment does not guarantee that all relevant differences have been addressed, and it cannot correct for factors not measured or not included in the model.

The record specifies least squares means for comparing the active group with the control device. In general, a least squares mean is an adjusted mean derived from the fitted model, rather than a simple arithmetic mean of the raw observations. The contrast between these means would describe the modeled difference between groups, conditional on the model and its covariates. The registry record does not provide the estimated means or contrast, so the size and direction of this adjusted comparison cannot be assessed.

Why use a continuous-outcome model?

General explanation: when an outcome is measured on a continuous scale, modeling its mean can use information about the magnitude of each observation rather than reducing results to categories. The mean is sensitive to the distribution of values and can be influenced by unusually high or low observations. The standard deviation describes variability around the mean, but it is not itself a measure of uncertainty in the estimated group contrast. For uncertainty about a contrast, an estimate and its standard error or confidence interval are needed. Those result quantities are not reported in the registry record.

The endpoint listing names the mean and standard deviation as its summary measures. The analysis description says a two-sided test was conducted at the 5% level of significance. General explanation: a two-sided test allows evidence in either direction to count against the null hypothesis of no group difference. A significance level sets a decision threshold for that test; it does not measure the probability that the null hypothesis is true, nor does it describe the magnitude or importance of a result. No test statistic or p-value is reported in the registry record.

Why model the follow-up times separately?

The registry's analysis description says Week 16 and Week 26 were modeled separately. In general, separate models produce a distinct estimate for each assessment time. That can make the time-specific comparisons easier to interpret, but it also means there can be more than one statistical test for the same primary outcome question. Whether an adjustment for testing across the two follow-up times was planned or used is not reported in the registry record. The record also does not explain how these time points were designated in relation to any hierarchy of outcomes or decision rules.

General explanation: repeated measurements from the same participant are often correlated. A model that analyzes each follow-up separately does not, by itself, describe the correlation between measurements across time. That may be appropriate for particular aims, but interpretation depends on the prespecified estimand, handling of missing observations, and any multiplicity strategy. The registry record does not report a repeated-measures model or provide enough detail to determine whether other approaches were used in the full analysis.

What can the planning assumptions tell us?

The record describes planning illustrations based on the observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. It states that the target effect is a stated fraction of the observed effect. General explanation: sample-size planning asks how much information a future study might need to detect a specified effect under chosen assumptions. Such an illustration depends on the effect used as its starting point and the model assumptions. It is not a measure of the probability that the completed trial detected an effect, and it cannot replace the trial's observed estimate and confidence interval. The observed effect and the numerical planning outputs are not reported in the registry record.

The registry does not provide diagnostics or assumptions for the ANCOVA, such as the approach to non-normal residuals, influential observations, or covariance structure. These details are not reported in the registry record. The analysis description is therefore useful for identifying the broad model and covariates, but it does not allow a full assessment of model fit, robustness, or reproducibility.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is assessed at Week 16 and Week 26, and the record describes a separate model at each time point. It specifies a two-sided test at the 5% level. The registry record does not report whether the significance threshold was adjusted across these assessments, whether one time point took priority, or whether a testing hierarchy was prespecified. When multiple tests address related questions, general statistical practice considers how the chance of false-positive findings is controlled or how results are interpreted jointly. The record does not report such a strategy, so the multiplicity approach cannot be evaluated.

Missing-data handling is not reported in the registry record. It does not state how participants with missing Week 16 or Week 26 measurements were handled, whether any imputation was used, or what assumptions were made about missingness. Nor does it report sensitivity analyses assessing how conclusions might change under alternative assumptions. General explanation: missing measurements can affect an estimate if the likelihood or pattern of missingness is related to outcome values or group assignment. The amount, timing, and reasons for missingness help readers judge that risk, but are not reported.

The analysis population is also not reported in the registry record. The record does not specify whether the primary analysis included all randomized participants, only participants who received their assigned device, or another defined group. It provides an enrollment figure of 72, but does not report participant flow through assignment, follow-up, and endpoint analysis. The safety risk sets are not identified as the primary outcome analysis population. As a result, the relationship between enrollment and the efficacy analysis cannot be established.

11. 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 3% reporting threshold.

The safety record lists a control-device group with 22 at risk and 0 affected by serious adverse events. It lists the HairMax LaserComb 2009 9 Beam group with 43 at risk and 0 affected by serious adverse events. These figures describe the registry's reported serious adverse event counts for the stated at-risk groups; they do not provide a detailed account of event surveillance or follow-up.

The record also reports 0 affected by other adverse events in each listed group. The death counts are null, so deaths are not reported in the registry record; a null entry should not be read as a reported count of zero. The registry does not list serious adverse event terms. It does not provide definitions, event timing, severity grading, relatedness assessments, withdrawals due to adverse events, or a narrative of how adverse events were collected.

General explanation: zero reported events in an at-risk group means that the record lists no affected participants for that event category in that group. It does not prove that an event is impossible or establish that risks are identical between groups. Interpretation also depends on the size and completeness of the safety population, duration and intensity of monitoring, and consistency of event ascertainment. The relationship between these safety counts and the trial's enrollment or efficacy analysis is not reported in the registry record.

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

The registry record establishes that a randomized, quadruple-masked, parallel-group device trial was conducted to evaluate terminal hair count in females diagnosed with androgenetic alopecia. It gives the primary measurement, follow-up times, broad model, covariates, and testing approach. Those details clarify what comparison was intended, but they do not supply its numerical findings.

The record does not report the observed group values or adjusted contrasts at Week 16 or Week 26. It therefore cannot show whether the active-device group had a higher, lower, or similar terminal hair count relative to the control group, nor how large or precise any contrast was. It also does not report p-values or confidence intervals. No conclusion about the statistical evidence or magnitude of the primary result can be drawn from the information recorded.

General explanation: a statistically significant result, if available, would not by itself establish that a difference is large or important. Conversely, a result that does not meet a significance threshold would not establish that the groups are equivalent. Those judgments require the estimated effect, its uncertainty, and a context for interpreting the outcome scale. Equivalence or non-inferiority claims also require a defined margin and suitable prespecified methods; these are not reported in the registry record.

The completed status and enrollment figure do not resolve the absence of results. They do not reveal how many participants contributed to each endpoint, whether measurements were missing, or whether the prespecified analysis was carried out as described. The safety listing reports no participants affected by serious adverse events in the at-risk groups, while death counts are not reported. These entries are limited safety information and cannot substitute for a complete account of trial outcomes.

The appropriate reading is therefore bounded: the registry record describes a trial question and a planned statistical approach, but does not report enough efficacy results to characterize what the trial found. It also does not provide enough information about participant flow, missing data, multiplicity, or analysis populations to assess how robust an outcome estimate would be. These gaps are limits on interpretation, not evidence that a particular result occurred.

13. Why This Trial Matters Statistically

This trial illustrates why a registry entry can identify a clear statistical question without establishing its answer. The primary endpoint is a continuous hair-count measure, and the analysis description specifies an adjusted comparison at two follow-up times. Listing the outcome scale, model, covariates, and test direction helps readers understand the intended analysis. Yet without estimates and uncertainty intervals, the record cannot convey the observed difference or how precisely it was measured.

The separate Week 16 and Week 26 analyses also highlight the importance of understanding how multiple assessments are interpreted. Testing at more than one time can create questions about multiplicity, priority, and consistency across time. The registry record does not report how these issues were handled. Likewise, identifying adjustment variables is only part of evaluating an analysis: readers also need information about missing measurements, the analyzed population, and model diagnostics.

The safety listing is another reminder that a zero count has a defined scope. It refers to the events and at-risk groups recorded, while the record leaves death counts unreported and gives little information about event ascertainment or follow-up. Safety numbers should be read alongside the population and monitoring details that produced them.

For biostatisticians and clinical researchers, the main statistical lesson is to distinguish design information from results. Randomization and masking describe intended safeguards; ANCOVA describes a planned approach; enrollment describes a registry count. None of these items supplies an estimated effect. The registry record is informative about the question and broad methods, while its missing efficacy and analysis details sharply limit what can be concluded from it.

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.

The primary limitation for interpretation is that numerical efficacy results are not reported in the registry record. Group summaries, baseline values, adjusted contrasts, uncertainty intervals, and test results are absent. This prevents assessment of the direction, magnitude, and precision of the primary comparison at either follow-up assessment.

The record does not report participant flow or clarify the relationship between its enrollment figure and the at-risk groups listed for safety. It does not state the numbers randomized, treated, followed, or included in the Week 16 and Week 26 analyses, or explain any exclusions. The efficacy analysis population and handling of missing outcome data are not reported in the registry record.

The two follow-up times are modeled separately, but the record does not describe any multiplicity strategy or prioritization between time points. It identifies covariates and a two-sided testing threshold, but does not report model diagnostics, sensitivity analyses, or details sufficient to assess robustness. Allocation concealment, the roles included in quadruple masking, adherence, and the control-device characteristics are also not reported in the registry record.

Safety information is limited to counts of affected participants in the listed at-risk groups and the absence of listed serious adverse event terms. Death counts are not reported. Details on event definitions, ascertainment, duration of monitoring, and relationship to treatment are not reported in the registry record. These limitations mean the available safety entries should be interpreted narrowly rather than as a comprehensive safety assessment.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Treatment of Androgenetic Alopecia in Females, 9 Beam — NCT00981461.
• Registry record last updated 2012-08-10; status last verified 2012-08.
• Results first posted 2012-07-30.
• 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.

18. Record Summary

NCT00981461 is listed as a completed randomized, quadruple-masked, parallel-group trial of the HairMax LaserComb 2009 9 Beam model versus a control device in females with androgenetic alopecia. The registry lists enrollment of 72, with a start of 2009-10 and primary completion of 2010-10.

The primary outcome is terminal hair count in hairs per cm^2 at baseline, Week 16, and Week 26. The planned analysis separately models follow-up count using treatment group, study center, age, and Fitzpatrick Skin Type classification, with adjusted least squares means and a two-sided test at the 5% level. Numerical efficacy results and the analysis population are not reported in the registry record.

The safety entry lists 0 serious adverse events and 0 other adverse events affected in each reported at-risk group. Death counts are not reported. The record does not provide enough outcome or participant-flow information to assess the primary comparison's magnitude or precision.