Efficacy Study of a New Antimicrobial Wound Dressing to Treat Wounds Caused by Curettage and Electrodesiccation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy Study of a New Antimicrobial Wound Dressing to Treat Wounds Caused by Curettage and Electrodesiccation (NCT00816101), a randomized phase 2 study. The primary outcome is Number of Patients Who Experienced 50% or Greater Wound Healing.

2. Clinical Question

The trial was randomized, used a parallel-group design, and had no masking reported. Its stated purpose was to compare healing rates, pain levels, and wound complications, including infection, for Procellera and a standard dressing. The posted outcome results also include the Band-Aid Adhesive Bandage group. The registry record does not report a formal primary comparison among the groups, so the posted counts should be read as descriptive results rather than as a complete answer to a comparative-effectiveness question.

The study record identifies two secondary outcomes: the number of patients reporting pain and erythema at Week 3. Results for those outcomes are not reported in the registry record. Nor does the record provide further detail about how pain was measured, how erythema was assessed, or how wound complications were defined. This limits how specifically the stated clinical questions can be connected to the posted results.

3. Trial Design

NCT00816101 is listed as a completed phase 2 randomized trial with a parallel design and no masking. The registry reports enrollment of 26. The study began in 2008-03, and primary completion was recorded as 2008-09. Vomaris Innovations is identified as the sponsor. The condition is acute wounds, and the study concerns wounds after curettage and electrodesiccation of skin lesions.

The three groups were Procellera Dressing, Mepilex Border Lite, and Band-Aid Adhesive Bandage. The registry lists 13 participants in the Procellera group, 8 in the Mepilex group, and 5 in the Band-Aid group. Dressing-change instructions differed: Procellera changes were scheduled every 3 days, more frequently if needed; the other dressings were to be changed every 2-3 days, more frequently if needed. These details describe the recorded treatment procedures, not whether participants followed them as intended.

Randomization can help reduce systematic differences between treatment groups, but the registry record does not report the sequence-generation method, allocation concealment, or any stratification factors. It also does not report why the group sizes differ. With no masking, knowledge of the assigned dressing could potentially influence subjective assessments or participant reports; the record does not describe steps taken to limit that possibility.

The registry labels the study as a pilot clinical study. It does not report a protocol-based sample-size justification or establish that the enrollment was chosen to support a definitive comparison. The stated purpose and completed status do not, by themselves, establish which analyses were planned or performed. A detailed statistical analysis plan is not reported in the registry 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

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 Patients Who Experienced 50% or Greater Wound Healing, measured over 3 Weeks.

The primary endpoint is the number of participants whose wound area was reduced by at least 50% at 3 weeks. It classifies each participant according to whether the wound met that threshold, then reports the count in each group. The posted results are 13 participants in the Procellera group, 7 in the Mepilex group, and 4 in the Band-Aid group. These are counts, not percentages or estimates of the average change in wound area.

A threshold-based endpoint can make a clinical outcome easier to interpret as a responder count: it distinguishes wounds meeting a specified healing criterion from those that do not. It can also provide a clear target for describing early wound progress. As a general statistical consideration, however, turning a continuous measurement such as wound area into a yes-or-no classification discards information about how much each wound changed. Participants just above and just below the threshold are classified differently, even if their measured changes are close, while different degrees of improvement on the same side of the threshold are grouped together.

The registry record does not report the method used to measure wound area, whether assessments were masked, or how missing measurements were handled. It also does not provide a continuous wound-area result. The count therefore answers the stated threshold question, but it does not describe the full distribution of wound healing or establish the precision of a comparison between dressings.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: each wound either met the threshold of at least 50% area reduction at 3 weeks or did not. The registry reports the number of participants meeting that definition in each group. This format is straightforward, but it is not itself a statistical comparison. A comparison requires a defined contrast between groups and an estimate of the size of that contrast.

What does a confidence interval add?

In general, a confidence interval gives a range of values compatible with an estimate under a specified statistical method. It communicates precision: a narrow interval indicates more precise information than a wide interval, while an interval spanning values on different sides of no difference can indicate that the data are compatible with more than one interpretation. A confidence interval is not a guarantee that the true effect lies within the reported range. No confidence interval for the primary outcome is reported in the registry record, so the precision of the group comparison cannot be judged from the posted counts alone.

Why does the outcome scale matter?

Because the primary endpoint is a participant count meeting a threshold, suitable analyses would need to account for a binary outcome. In general, possible summaries include the proportion meeting the threshold in each group and a contrast between groups, with uncertainty calculated using an appropriate method. Those are general options, not claims about what this trial's investigators used. No such comparative estimate is reported in the registry record, and no new proportion or contrast is calculated.

Threshold outcomes also have limitations. They retain whether each participant met a prespecified criterion, but do not retain the degree of wound-area change within either outcome category. A continuous outcome can preserve more information about the observed measurements, although its analysis requires appropriate assumptions about the data. The registry record does not report a continuous wound-area analysis or enough information to assess whether one was performed.

What can randomization and masking tell us?

Randomization is intended to make treatment assignment independent of participants' characteristics, on average, and can support a causal comparison when the study is properly conducted and analyzed. In a trial with limited enrollment, chance imbalances can still occur. The registry reports randomization but does not report the random-sequence method, allocation concealment, baseline characteristics, or a statistical adjustment plan. It is therefore not possible to assess those features from the registry record.

No masking is reported. In general, masking can reduce the chance that expectations affect subjective reporting or outcome assessment. Its absence does not automatically invalidate a result, but it can matter when outcomes involve judgment or participant reports. The wound-healing threshold may depend on how area is measured, while pain is participant-reported by its nature. The registry record does not describe who assessed wound area, whether standardized procedures were used, or how assessors' knowledge of dressing assignment was handled.

What is and is not known about the analysis?

The registry record lists no analysis entries for the primary outcome. It does not report an analysis population, such as whether results were based on all randomized participants, those who received a dressing, or those with an available outcome measurement. It also does not report a missing-data method, a prespecified statistical test, adjustment for baseline values, or adjustment for multiple outcomes. These omissions prevent a reconstruction of the planned analysis or an assessment of whether the posted counts reflect all randomized participants.

The record indicates that values are missing or not estimable for a two-arm comparison of this binary endpoint. A recalculated comparison would require enough information to define and estimate that contrast. Since no such recalculation is available, no derived test statistic or effect estimate should be inferred from the separate group counts. The record shows no discrepancy between a sponsor analysis and a recalculation; there is no sponsor analysis in the posted results to use for that purpose.

How should planning illustrations be understood?

Sample-size illustrations based on an observed effect are planning scenarios, not observed power and not a report of the trial's original design justification. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. The registry record does not report that these assumptions were used to design this trial. Such illustrations describe hypothetical planning choices; they do not change the evidence represented by the observed counts or supply a missing uncertainty estimate.

In general, over-dispersion matters when observations vary more than a statistical model assumes. If a model underestimates that variability, standard errors can be too small and confidence intervals too narrow. The posted primary result is a count of participants crossing a threshold, and the registry does not report a model-based analysis or evidence of over-dispersion. This concept is therefore general rather than a claim that over-dispersion affected this study.

The distinctions are important: a descriptive count tells what was recorded; an effect estimate expresses a comparison; an uncertainty interval conveys how precisely that comparison is known; and a planning illustration concerns a hypothetical future design. Only the descriptive group counts are posted for this primary endpoint. The other quantities and methods are not reported in the registry record.

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("Procellera Dressing", "Mepilex® Border Lite", "Band-Aid® Adhesive Bandage")
n      <- c(13, 8, 5)
events <- c(13, 7, 4)
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  Procellera Dressing  13  13  100.0  75.3  100.0  77.2  100.0  76.8  99.8
ARM  Mepilex® Border Lite  8  7  87.5  47.3  99.7  52.9  97.8  51.8  97.2
ARM  Band-Aid® Adhesive Bandage  5  4  80.0  28.4  99.5  37.6  96.4  35.9  95.7

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies the primary wound-healing threshold outcome and lists two secondary outcomes: number of patients reporting pain and erythema at Week 3. Results for those secondary outcomes are not reported in the registry record. The record does not describe a hierarchy among outcomes beyond identifying the primary outcome, nor does it state whether any adjustment for multiple comparisons was planned or used.

As a general statistical issue, evaluating several outcomes or several group contrasts can increase the chance of finding an apparently notable result by chance if each is assessed separately. A prespecified hierarchy or multiplicity adjustment can address that issue, depending on the scientific question and analysis plan. Neither approach is described in the registry record, so it is not possible to determine how multiplicity was handled.

Missing-data handling and analysis populations are also not reported in the registry record. The listed group sizes and outcome counts do not establish whether every randomized participant had an assessed outcome or how any unavailable assessment was treated. The record does not specify an intention-to-treat population, a per-protocol population, or another analysis set. Consequently, the relationship between enrollment, analyzed participants, and missing outcome data cannot be fully evaluated from the posted information.

The registry lists no analysis entries for these results. It also does not report whether analyses were prespecified, whether interim analyses occurred, or what statistical plan governed the completed trial. Those details should not be inferred from the trial's phase, randomization, or completion status.

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.

The registry reports 0 serious adverse events among 13 participants at risk in the Procellera group, 0 among 8 at risk in the Mepilex group, and 0 among 5 at risk in the Band-Aid group. It also reports 0 other adverse events among the participants listed as at risk in each of those groups. These are the recorded counts for the registry's serious and other adverse-event categories.

A count of zero recorded events does not show that a treatment is free of risk. Safety counts depend on what was collected, how events were defined, how long participants were followed, and how completely events were reported. The registry record does not provide further details about adverse-event definitions, surveillance procedures, or the safety follow-up period. Death counts are not reported in the registry record; they should not be read as zero.

The groups are small, and the registry does not report an uncertainty analysis for adverse events. Therefore, the absence of recorded events in these categories is a descriptive finding, not a precise comparison of safety between dressings or evidence that uncommon harms could be excluded.

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

The posted result shows that 13 participants in the Procellera group, 7 in the Mepilex group, and 4 in the Band-Aid group met the primary threshold of at least 50% wound-area reduction at 3 weeks. It also records 0 serious and 0 other adverse events in each group among those listed as at risk. These statements describe the registry results; they do not establish a treatment effect or a complete safety profile.

The results do not show how large the difference between groups is with statistical precision. The registry record does not report a confidence interval, p-value, or formal comparative analysis for the primary outcome. It also does not provide results for the listed pain and erythema outcomes. Without those results, the study's broader questions about discomfort and complications remain unanswered by the posted outcome data.

Meeting the threshold is not equivalent to complete wound healing. It does not describe the amount of area reduction for each participant, the time to healing, wound status after 3 weeks, or whether infection occurred. The wound-healing count is one defined measure at one follow-up point. The record does not establish whether the threshold was the only measure of healing collected.

The randomized design is relevant because it was intended to support group comparisons, but the available registry record does not include key details about allocation, outcome assessment, missing data, or analysis. Those limits make it inappropriate to treat differences in the observed counts as conclusive evidence of a causal effect. The study's pilot designation and enrollment also mean that its role is descriptive and exploratory as recorded; the registry does not report a design justification that would establish the precision intended for the comparisons.

Any sample-size illustrations based on the observed effect are planning scenarios. They are not observed power, do not describe the original trial design, and cannot remedy the absence of a reported comparative analysis. The most defensible interpretation is therefore limited: the registry records the number meeting the wound-healing threshold in each group, while the magnitude and precision of any between-group difference remain unreported.

14. Why This Trial Matters Statistically

This trial is statistically instructive because its headline endpoint is a threshold-based participant count, while the clinical question is comparative. The distinction matters: counts in separate groups can describe observed outcomes, but a reader needs a defined contrast and its uncertainty to judge the evidence for a difference. The registry record gives the counts but does not report that comparative estimate.

The study also illustrates why outcome definition matters. A 50% wound-area reduction threshold creates a simple responder classification at 3 weeks. That can be easier to communicate than a distribution of measurements, but it compresses the underlying wound-area information into a yes-or-no result. A full account of the endpoint would ideally make clear how area was measured and how incomplete assessments were handled; those details are not reported in the registry record.

Randomization and lack of masking raise distinct methodological questions. Random assignment is relevant to confounding, whereas masking is relevant to the influence of expectations on assessments and reports. The registry identifies randomization and no masking, but does not report the sequence-generation or outcome-assessment procedures. Those omissions make the design harder to appraise than the labels alone suggest.

Finally, the record distinguishes descriptive safety counts from a comparative safety analysis. Zero recorded adverse events in the listed categories is informative as a description, but does not quantify uncertainty or exclude unrecorded or uncommon events. Together, these features make the trial a useful example of how registry results can document observed outcomes while leaving important questions about estimation, precision, and analysis unresolved.

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 registry provides limited detail about the enrolled population. It identifies acute wounds after curettage and electrodesiccation of skin lesions, but eligibility criteria, baseline wound characteristics, participant demographics, and other prognostic factors are not reported in the registry record. Without that context, it is difficult to assess how broadly the results apply to other wounds or settings.

Several design details are also absent. The record does not report the randomization sequence method, allocation concealment, or the reason for the observed group sizes. It gives dressing-change instructions but does not report adherence, treatment changes, or deviations from those instructions. No masking was used, and the wound-area assessment method and assessor procedures are not described.

The primary outcome is reported at 3 weeks, with no longer-term wound-healing outcome stated in the posted results. The record does not describe the measurement technique, provide continuous wound-area changes, or explain handling of missing measurements. It lists pain and erythema as secondary outcomes, but their results are not reported in the registry record. The study purpose mentions wound complications, including infection, but the posted information does not provide a separate infection outcome result.

The registry reports enrollment of 26 and describes the study as a pilot, but does not report a trial-specific sample-size justification. No comparative analysis, uncertainty interval, or statistical analysis plan is reported. The record also does not specify the analysis population or missing-data approach. These limitations mean the available counts should be treated as descriptive and should not be used to infer a precise treatment difference or definitive safety comparison.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy Study of a New Antimicrobial Wound Dressing to Treat Wounds Caused by Curettage and Electrodesiccation — NCT00816101.
• Registry record last updated 2011-03-09; status last verified 2011-03.
• Results first posted 2011-03-01.
• 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

NCT00816101 is a completed randomized phase 2 parallel-group study sponsored by Vomaris Innovations. It enrolled 26 participants with acute wounds following curettage and electrodesiccation of skin lesions. The registry lists no masking. The study began in 2008-03, with primary completion in 2008-09.

The three dressing groups were Procellera, Mepilex Border Lite, and Band-Aid Adhesive Bandage. The primary endpoint was the number of participants whose wound area was reduced by at least 50% at 3 weeks. The posted counts were 13, 7, and 4, respectively. The listed secondary outcomes were number of patients reporting pain and erythema at Week 3; their results are not reported in the registry record.

The registry records 0 serious and 0 other adverse events in each group. Death counts, comparative effect estimates, confidence intervals, p-values, analysis populations, and missing-data methods are not reported in the registry record. The results therefore support a descriptive account of the posted counts, not a quantified comparison between dressings.