Safety and Efficacy Evaluation of Erbium Treatment: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy Evaluation of Erbium Treatment (NCT00766376), a na na study. The primary outcome is Number of Participants That Scored Above a One Category (Mild) Improvement Using the Fitzpatrick Wrinkle Scale..

2. Clinical Question

The clinical question is descriptive rather than comparative. It asks whether participants met a specified wrinkle-improvement threshold after treatment, not whether treatment produced a better outcome than another treatment or no treatment. Without a concurrent comparison group, changes over time cannot be separated from other influences, such as natural variation or differences in photographic assessment.

The registry also lists reduction in pigmented lesions and dyschromia as a secondary outcome. The number of outcome measures is reported as 2, but outcome results are not included in the registry record. The primary endpoint definition is available, while the number of participants who met its threshold is not reported in the registry record.

3. Trial Design

The registry record describes an interventional device study of erbium laser treatment for skin aging. The listed sponsor is Palomar Medical Technologies, Inc. The study model is single group, with no comparator arm. Allocation is listed as NA, and masking is listed as none. The record lists phase as NA.

Enrollment is recorded as 151. The study start is listed as 2007-07 and primary completion as 2009-07. The current status is recorded as UNKNOWN. These registry fields describe the record; they do not establish how many participants completed treatment or contributed data to each outcome. Those details are not reported in the registry record.

The primary outcome is a count of participants who scored above a mild, one-category improvement on the Fitzpatrick Wrinkle Scale at three months. Three blinded evaluators assessed photographs from before and after treatment. Blinded evaluation can reduce the influence of knowledge about the assessment on scoring, but the overall study is listed as unmasked. The registry record does not explain the practical arrangements for evaluator blinding or how disagreements among evaluators were handled.

Because the study has a single group, its primary outcome can describe how many participants met the defined threshold, if that count is reported. It cannot, by itself, estimate a treatment difference against a control group. The registry record does not report a protocol, randomization procedure, comparator, or statistical analysis plan. The number of analyses is recorded as 0, and no analysis results are included in the record.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants That Scored Above a One Category (Mild) Improvement Using the Fitzpatrick Wrinkle Scale., measured over participants at three months.

The primary endpoint is the number of participants who scored above a one-category, mild improvement in wrinkles using the Fitzpatrick Wrinkle Scale. The registry describes the scale as ranging from 0, no wrinkles, to 9, severe wrinkles. Evaluators score pre-treatment and post-treatment photographs for wrinkles, fine lines, and the severity of skin elastosis. The difference between scores is described as the amount, or category, of wrinkle improvement.

The endpoint turns a graded assessment into a threshold outcome: a participant either meets the stated improvement criterion or does not. A threshold can make a result easier to communicate as a count, but it leaves out how far beyond the threshold a participant's score may have changed. It also does not show the full distribution of score changes. The registry record does not report those underlying scores or the number meeting the threshold.

The endpoint is assessed at three months. That timing defines when the outcome is evaluated, but the registry record does not state whether additional follow-up was planned or report results at other times. The use of blinded evaluators is relevant because wrinkle ratings involve judgment; however, blinding does not replace a comparison group, and the record does not describe how evaluator scores were combined.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a binary primary outcome: participants are counted according to whether they meet the wrinkle-improvement threshold. A binary outcome distinguishes categories rather than measuring each participant's exact degree of change. In general, such outcomes can be reported as counts and proportions, with uncertainty described by a confidence interval. The registry record does not report the primary count, a proportion, a confidence interval, or a statistical test.

What does the threshold represent?

The Fitzpatrick Wrinkle Scale is described as a 0 to 9 scale, with 0 meaning no wrinkles and 9 meaning severe wrinkles. Three blinded evaluators assign scores to pre-treatment and post-treatment photographs. The difference in scores represents the amount of improvement, and a one-category change is defined as mild improvement. The primary outcome counts participants whose score is above that one-category improvement level. This converts a graded assessment into a yes-or-no classification. In general, thresholds simplify interpretation but can conceal differences among participants who fall in the same category.

What would a confidence interval tell a reader?

In general, a confidence interval expresses the uncertainty around an estimated outcome, such as the proportion of participants meeting a criterion. A narrower interval indicates greater precision under the method's assumptions; a wider interval indicates less precision. It does not show that the estimate is free of bias, and it does not address the absence of a control group. No confidence interval for the primary outcome is reported in the registry record, so its precision cannot be assessed from the posted primary outcome information.

What can a single-group design estimate?

A single-group study can describe outcomes observed among participants who received the intervention, provided those results are reported. It does not include a concurrent control group for estimating a treatment contrast. In general, a before-and-after comparison may be influenced by factors other than treatment, including changes over time and variation in measurement. A blinded evaluator may reduce the influence of treatment knowledge on ratings, but it does not remove all potential sources of bias or create a control comparison. The registry record does not report a control group or a comparative analysis.

How should the planning illustrations be read?

The sample-size illustrations are planning calculations based on the observed effect, not the study's own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target effect is described as a stated fraction of the observed effect. These assumptions describe a hypothetical two-arm planning exercise, whereas this trial is listed as single group. The illustrations therefore should not be read as the trial's enrollment target, its observed power, or evidence of a randomized comparison. No sample-size illustration results or observed primary effect are reported in the registry record.

In general, a planning calculation asks how much information a future study might need under specified assumptions. Its output depends on the assumed effect and design. When an effect is estimated from observed data, that estimate itself is uncertain; planning around it does not guarantee that a future study will produce the same effect. The planning assumptions do not substitute for a protocol or a documented rationale for the original enrollment. A sample-size justification for this study is not reported in the registry record.

What analyses are documented?

The record lists 2 outcome measures and 0 analyses. It does not describe a statistical model, an adjustment strategy, a hypothesis-testing plan, or an approach to missing data. In general, an analysis plan specifies how outcomes will be calculated and how uncertainty will be quantified. Without a documented plan and posted results, readers cannot determine whether the endpoint was analyzed as intended or whether any additional analyses were performed.

There is no indication in the registry record of a randomized comparison, an interim analysis, or an adjustment for multiple testing. These elements should not be assumed. The record also does not report the full score distribution, participant-level data, evaluator agreement, or sensitivity analyses. As a result, statistical interpretation is limited to the stated design and endpoint definition, plus the reported adverse-event counts.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Erbium Laser")
n      <- c(151)
events <- c(124)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Erbium Laser  151  124  82.1  75.1  87.9  75.2  87.4  75.2  87.4

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures: the primary wrinkle-improvement endpoint and a secondary outcome concerning reduction in pigmented lesions and dyschromia. It records 0 analyses and reports no outcome results. The record does not describe how the primary and secondary outcomes were prioritized in statistical testing or whether any adjustment for multiple testing was planned.

In general, testing multiple outcomes can increase the chance of finding an apparently notable result by chance if each is assessed separately. Statistical plans sometimes address this by defining a primary outcome, controlling error rates, or treating secondary outcomes as exploratory. The registry record does not report such a plan, so it is not possible to assess how multiplicity was handled.

Missing-data methods and analysis populations are also not reported in the registry record. Enrollment is listed as 151, but the number contributing to the primary outcome and the reasons for any missing assessments are not stated. The safety summary uses 124 participants at risk, but the record does not explain whether that group corresponds to the efficacy population or how participants were selected for either assessment.

In general, missing outcomes can affect both the estimated result and its precision, particularly if the likelihood of missingness is related to participants' outcomes. Without information about completion, exclusions, and the handling of missing observations, readers cannot judge those effects. The registry record also does not report a prespecified analysis population, such as all enrolled participants or participants with an evaluable follow-up assessment.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The serious adverse event summary lists the Erbium Laser group with 124 participants at risk and 0 participants affected by serious adverse events. The registry also lists 124 participants at risk and 124 affected in the other adverse-event category. No serious adverse event terms are listed.

These are the counts recorded in the registry. A count of 0 serious adverse events means none were reported in the listed risk group; it does not establish that serious events cannot occur or that all possible events were captured. The registry record does not describe the follow-up period for these safety counts, how events were collected, or the definitions used for the other adverse-event category.

The adverse-event denominator is not the same as the enrollment figure in the record, and the reason for that difference is not reported in the registry record. The counts should not be combined with enrollment or interpreted as a complete account of all participants' experience. The record provides no event-level details for the serious adverse events category beyond the reported count.

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

The registry record documents an evaluation of erbium laser treatment and specifies a wrinkle-improvement endpoint at three months. It also records safety counts, including 0 serious adverse events among 124 participants at risk. These details describe what the registry reports about the study design, outcome definition, and safety summary.

The record does not report how many participants met the primary improvement threshold. It therefore does not establish the observed frequency of that outcome or its statistical precision. The secondary outcome result is also not reported. With 0 analyses recorded, there is no posted inferential result to interpret for either outcome.

The single-group design is important when considering what an outcome could mean. A change from pre-treatment to post-treatment can be described, but without a control group it cannot establish how the same participants would have fared without the intervention or under another approach. Evaluator blinding is noted for the wrinkle assessment, but the record does not detail how that blinding was implemented or how ratings were combined.

The safety count of 0 serious adverse events is a registry-reported observation in the listed risk group, not proof of no risk. The record does not give enough detail about safety follow-up and event collection to evaluate how complete the report is. Likewise, the enrollment and adverse-event denominators should be kept distinct because the registry does not explain their relationship.

In short, the record allows readers to identify the question the study set out to address and the limits of its design. It does not provide the primary outcome result needed to describe the observed wrinkle response, and it does not support a comparative conclusion about treatment effects.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint definition and an endpoint result are different kinds of information. The registry describes a specific threshold based on photograph ratings, but does not report the count of participants who crossed it. Knowing the scale, assessment timing, and threshold clarifies what would be measured; it does not reveal what was observed.

It also illustrates the distinction between within-group change and comparative evidence. A before-and-after assessment can describe change in a treated group, but a single-group design cannot isolate the contribution of treatment from other influences. Blinded evaluators may reduce one potential source of measurement bias, yet evaluator blinding does not supply a control group.

The record also demonstrates why denominators need context. Enrollment is listed as 151, while the safety summary lists 124 participants at risk. Without an explanation of follow-up, analysis populations, or participant flow, these figures answer different registry questions and should not be combined or treated as interchangeable.

Finally, planning calculations need to be separated from observed trial evidence. The record describes hypothetical sample-size assumptions for a two-arm design, while the study itself is listed as single group. Such illustrations can support planning under stated assumptions, but do not establish the study's own power or replace its missing outcome results. The registry record is therefore informative about design and measurement, while limited for assessing efficacy and statistical uncertainty.

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 limitation for interpreting the primary outcome is that its observed count is not reported in the registry record. The record also does not include the score changes underlying the threshold, evaluator-level ratings, or a description of how the three evaluators' assessments were combined. Those omissions prevent assessment of the distribution of responses and consistency of scoring.

The single-group design has no concurrent comparator, and allocation is listed as NA. The record therefore does not provide a randomized or controlled estimate of a treatment contrast. Masking is listed as none, although the primary outcome description says that evaluators were blinded. Details of the blinding procedure, and whether it was maintained, are not reported in the registry record.

Participant flow is not described. The record lists enrollment as 151, but gives no number assessed for the primary endpoint, no completion information, and no reasons for missing assessments. It also does not explain why the safety summary reports 124 participants at risk. The relationship between efficacy and safety populations is not reported in the registry record.

The record does not report a statistical analysis plan, a sample-size justification for the trial, handling of missing data, or an approach to multiplicity. It lists 0 analyses, and neither primary nor secondary outcome results are reported. Follow-up details beyond the primary assessment at three months, as well as methods for collecting safety events, are not reported in the registry record. These limitations restrict both the assessment of outcome precision and the interpretation of the posted safety counts.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety and Efficacy Evaluation of Erbium Treatment — NCT00766376.
• Registry record last updated 2010-01-29; status last verified 2010-01.
• Results first posted 2010-01-29.
• 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

NCT00766376 is a single-group evaluation of erbium laser treatment for skin aging. The registry lists enrollment as 151, allocation as NA, masking as none, and phase as NA. The primary outcome is the number of participants with more than a mild, one-category improvement on the Fitzpatrick Wrinkle Scale at three months, assessed from pre-treatment and post-treatment photographs by three blinded evaluators.

The registry lists a secondary outcome concerning reduction in pigmented lesions and dyschromia. It reports 0 analyses and does not include primary or secondary outcome results. The safety summary lists 0 serious adverse events among 124 participants at risk and 124 affected in the other adverse-event category among 124 at risk. The record's current status is UNKNOWN. It does not explain the relationship between the enrollment and safety figures or report the analysis population.