Vashe Wound Therapy Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Vashe Wound Therapy Study (NCT00586729), a non-randomized na study. The primary outcome is Percentage of Grafted Area That is Viable at Day 14.

2. Clinical Question

The clinical question is framed around graft viability after the two wound-treatment approaches. The study also lists length of stay and hospital cost per patient as secondary outcomes. It does not report results for those outcomes in the registry record. Because the allocation was non-randomized, differences between groups cannot automatically be attributed to the treatment approach: participants receiving each treatment may have differed in other ways. The record does not describe whether or how those potential differences were addressed.

3. Trial Design

This completed study is titled the Vashe Wound Therapy Study and is identified as NCT00586729. Its official title describes it as a pilot study evaluating Vashe Wound Therapy as an antimicrobial irrigant in burn wound management. The registry lists the phase as not applicable and records an enrollment of 23. Valleywise Health is listed as the sponsor. The study started in 2009-07, had primary completion in 2010-11, and has a completed status.

The design is parallel, with non-randomized allocation and no masking. One group received Vashe and the other received 5% Mafenide Acetate. Both treatments were applied to gauze dressing every 6 hours or as needed to keep the dressing moist, for a total treatment duration of 5 days. The registry record does not report how treatment assignment was determined, whether assignment procedures changed during the study, or what features were considered when placing participants in groups.

These design features matter when interpreting a group comparison. Random allocation is a general method for balancing measured and unmeasured participant characteristics across groups; it was not used in this study. Masking can reduce the influence of expectations on assessment or care; the record lists no masking. Since the primary outcome involves clinical assessment, the lack of masking is relevant to interpretation, although the record does not describe how assessments were conducted or whether assessors knew the treatment received.

The primary endpoint is the percentage of grafted area that is viable at day 14, assessed in the per-protocol population. Length of stay and hospital cost per patient are listed as secondary outcomes. The registry record does not report a sample-size justification, a detailed protocol, or methods for controlling differences between the non-randomized groups. It also does not report the number of participants in each group for the primary endpoint or the results of a treatment comparison.

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

Analysis population for the primary outcome, as defined in the registry: Per protocol

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 Percentage of Grafted Area That is Viable at Day 14, measured over 14 days.

The primary endpoint is the percentage of grafted area that is viable at day 14. The registry describes viability as determined by clinical assessment of revascularization, adherence of the graft to the wound bed, and color. The unit is percentage area, and the endpoint is defined as a mean with standard deviation. Its timeframe is 14 days, and the stated analysis population is per protocol.

This endpoint gives a quantitative description of the assessed portion of grafted area meeting the clinical criteria for viability. In general, a continuous measure can retain more gradation than a simple classification into success or failure, because different observed percentages can be represented. The mean describes the central level of the measure within a group, while the standard deviation describes variation among individual observations. These are general interpretations of the stated summary measure, not reported findings from this study.

The registry record does not report group means, standard deviations, the number assessed, or a between-group estimate for this endpoint. It also does not provide further operational details about the clinical assessment, such as assessor training, assessment procedures, or how disagreements were handled. The listed assessment criteria establish what the registry says the endpoint concerns, but do not by themselves establish how consistently it was measured.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary measure represent?

The primary outcome is a continuous measure: the percentage of grafted area assessed as viable at day 14. The registry specifies a mean and standard deviation as its summary format and identifies the analysis population as per protocol. In general, a mean is an average across the observations included in an analysis. A standard deviation describes how spread out those observations are around the mean. They answer different questions: the mean describes the group’s average level, while the standard deviation describes participant-to-participant variability.

A mean and standard deviation alone do not show how precisely a group mean or group difference has been estimated. In general, a confidence interval is a range of values compatible with the data under a specified statistical method; its width reflects uncertainty. The registry record does not report confidence intervals, group means, standard deviations, or a treatment contrast for the primary endpoint, so precision cannot be assessed from the primary results recorded there.

Why does the allocation method matter?

Allocation was non-randomized. In general, randomization uses chance to assign participants and can help balance prognostic characteristics between groups. Without randomization, the groups may differ in relevant ways before treatment. If an outcome differs between groups, the difference may reflect treatment or those underlying differences. The registry record does not report the allocation procedure, baseline characteristics, or an adjusted comparison for the primary endpoint. It is therefore not possible to assess from the registry record whether potential confounding was measured or addressed.

The study is listed as parallel, meaning the registry describes separate groups receiving the respective interventions rather than a crossover arrangement. It also lists no masking. In general, masking can limit the influence of knowledge about treatment assignment on care or outcome assessment. Since the endpoint includes clinical judgments about graft revascularization, adherence, and color, lack of masking may be relevant. The registry record does not say who performed the assessments or whether assessment procedures included safeguards against differences in judgment.

What does per protocol mean in this record?

The primary endpoint population is labeled per protocol. In general, a per-protocol analysis focuses on participants considered to have followed the study requirements, but the exact definition depends on the study’s protocol and analysis plan. The registry record does not state which participants qualified, what deviations counted, or how exclusions were handled. It also does not report the number included in the per-protocol analysis. As a result, the label alone does not establish how the analysis population was formed or how it may differ from all enrolled participants.

What is known about the analysis plan?

The registry record lists three outcome measures and zero analyses. It gives the primary endpoint definition and names length of stay and hospital cost per patient as secondary outcomes, but does not report estimates or statistical tests for them. The statistical analysis plan, model specifications, covariate selection, handling of repeated or incomplete measurements, and any interim analyses are not reported in the registry record. These details should not be inferred from the endpoint description or study title.

The record includes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The illustration considers effects stated as fractions of the observed effect. Such sample-size calculations are planning aids: they describe the sample size associated with specified assumptions and a target power, rather than the study’s observed power. The record explicitly distinguishes this planning illustration from the trial’s own design. The trial’s sample-size justification is not reported in the registry record, and the illustration does not supply an efficacy result.

How should uncertainty and dispersion be understood?

For a continuous outcome, variability among individual observations matters when estimating a group mean and comparing groups. In general, greater dispersion makes a mean less precise when other features are held constant. A confidence interval combines information about the estimate and its uncertainty, while a p-value addresses compatibility with a specified null model under its assumptions. Neither is reported for the primary comparison in the registry record. Their absence means that statistical significance and precision cannot be evaluated from the recorded primary outcome results.

General statistical methods must be interpreted in light of design and measurement. A model can adjust for measured characteristics, but adjustment cannot automatically remove bias from factors that were not measured or not modeled. Likewise, a small p-value, if reported, would not by itself establish causality or clinical importance. No model-based primary comparison or estimate is reported in this registry record, so those interpretations do not apply as findings of this study.

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("Vashe", "5% Mafenide Acetate")
n   <- c(9, 7)
m   <- c(96.3, 96)
sp  <- c(7.05, 3.83)
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  Vashe  9  96.300  7.050  90.881  101.719
CARM  5% Mafenide Acetate  7  96.000  3.830  92.458  99.542

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary endpoint and two named secondary outcomes: length of stay and hospital cost per patient. It also records three outcome measures and zero analyses. Although the outcomes are identified, the record does not report which statistical tests or models were planned for them, whether any outcomes were designated for particular analyses, or whether adjustments for multiple comparisons were planned. Those details are not reported in the registry record.

In general, examining multiple outcomes or conducting multiple comparisons can increase the chance that at least one result appears noteworthy by chance. Multiplicity methods are sometimes used to control that risk, but the appropriate approach depends on the planned questions and analysis strategy. There is no reported multiplicity procedure to evaluate for this study, and no outcome-level analyses are recorded. The absence of reported analyses should not be interpreted as evidence that a multiplicity adjustment was or was not performed outside the registry record.

The primary outcome population is described as per protocol. The registry record does not define that population or state the number of participants with day-14 assessments. It does not report missing outcome counts, reasons for missingness, imputation procedures, or sensitivity analyses. These omissions prevent assessment of how incomplete follow-up or exclusions may have affected the endpoint estimate. The record does not report an intention-to-treat analysis or explain how participants who did not follow the treatment regimen were handled.

In general, missing-data methods rely on assumptions about why observations are unavailable. Those assumptions can affect estimates, especially when missingness is related to outcome status or treatment group. Without counts and a stated handling strategy, the impact of missing data cannot be assessed. The same limitation applies to the secondary outcomes: their analysis populations and completeness are not reported in the registry record.

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

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cellulitis (12.5%), mrsa infection (9.1%), proteinuria (9.1%).

The registry safety summary reports serious adverse events among 2 of 11 participants at risk in the Vashe group and 1 of 8 participants at risk in the 5% Mafenide Acetate group. For other adverse events, it reports 11 of 11 at risk in the Vashe group and 8 of 8 at risk in the 5% Mafenide Acetate group. These are counts of participants affected and participants at risk as recorded in the registry; they are not primary efficacy outcomes.

The record lists cellulitis at 12.5%, MRSA infection at 9.1%, and proteinuria at 9.1% among the top serious adverse-event terms. It does not identify the group attribution or denominator for these percentages in the posted safety summary, so they should not be assigned to a treatment group or reinterpreted as group-specific rates. Deaths are not reported in the registry record.

In general, adverse-event counts are descriptive. Differences between groups in a non-randomized study do not by themselves establish that treatment caused an event or changed its risk. The registry record does not report event timing, severity details beyond the serious/other categories, exposure-adjusted analyses, or a formal between-group safety comparison. The counts should therefore be read as recorded safety summaries, not as a definitive comparative estimate.

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

The registry record establishes that a completed, non-randomized pilot study compared Vashe wound therapy with 5% Mafenide Acetate for burn wound management. It describes the primary question as the percentage of grafted area viable at day 14, assessed clinically in a per-protocol population. It also lists length of stay and hospital cost per patient as secondary outcomes. These details define the study question, but they are not findings about the relative performance of the treatments.

The registry record does not report primary outcome values, group means, standard deviations, or a treatment comparison. It also does not report analyses for the listed secondary outcomes. Therefore, the posted results do not establish whether one group had a higher or lower day-14 viability measure, how large any difference was, or how precise an estimate might be. A missing result is not a finding of no difference.

The design further limits what a group comparison could establish. Because allocation was non-randomized, pre-existing differences between participants may affect outcomes. The study is also listed as unmasked, and the endpoint includes clinical assessment. The record does not report how assignment or assessment procedures were managed, or whether potential confounding was addressed. These features warrant caution in interpreting any comparative result, even if additional outcome information becomes available.

The serious and other adverse-event summaries describe affected participants, but they do not provide a complete comparative safety analysis. The serious-event terms are reported with percentages whose group attribution and denominator are not identified in the registry record. The safety summaries should not be treated as proof of a treatment effect.

In general, a pilot study can contribute information about feasibility and generate questions for further evaluation, but the registry record does not report a specific feasibility analysis or study objectives beyond those stated. The available record supports describing the design and planned endpoints; it does not support a conclusion about efficacy, comparative safety, or clinical benefit.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of how design and reporting shape interpretation. Its primary endpoint is a continuous clinical measure, the percentage of grafted area assessed as viable at day 14. A clearly defined measure and timeframe help identify what the study intended to assess. The endpoint description also names clinical features used in the assessment, making clear that the measure depends on judgment as well as a percentage scale.

At the same time, the non-randomized allocation highlights the distinction between an observed group difference and a treatment effect. In general, random assignment helps limit systematic differences between groups, while non-randomized assignment can leave confounding. The registry record does not describe the assignment process or an adjustment strategy. This makes design information central to any interpretation of a comparison.

The study also shows why outcome reporting must include estimates and uncertainty, not just endpoint definitions. The registry record identifies the primary and secondary outcomes but reports zero analyses. Without group results, an effect estimate, or an uncertainty measure, readers cannot judge the magnitude, precision, or statistical compatibility of the outcome comparison. Enrollment alone cannot fill that gap because the number analyzed for the primary endpoint is not reported.

Safety data require similar care. Counts of participants affected provide a descriptive account, but a comparative interpretation depends on context such as group composition, event definitions, timing, and denominators. The record presents some of these elements but does not report a formal safety comparison or clear group attribution for the listed serious-event percentages.

These issues are broadly relevant to clinical research: a defined endpoint does not substitute for results, and a reported result does not erase limitations of the design or measurement. Here, the registry record allows the study question and key design features to be identified, while leaving the efficacy analyses and important analysis details unreported.

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 are specific to the information recorded for this study. Allocation was non-randomized, and masking was absent. The registry record does not describe how participants entered either group, which characteristics informed treatment assignment, or whether group differences were addressed analytically. Consequently, any group comparison would be vulnerable to confounding, and the record does not permit assessment of the extent of that risk.

The primary endpoint relies on clinical assessment of revascularization, graft adherence to the wound bed, and color. The record does not report who conducted these assessments, whether assessors were trained or standardized, or how disagreements were resolved. Because no masking is listed, the influence of knowledge of treatment assignment on assessment cannot be evaluated from the record.

Although enrollment is recorded as 23, the registry does not report the group-specific primary analysis sample sizes, the number with day-14 assessments, or the number included in the per-protocol population. Definitions of protocol adherence, exclusions, and missing-data handling are also not reported in the registry record. These gaps limit assessment of attrition and the representativeness of the analyzed participants.

Most importantly, the registry record lists zero analyses and provides no primary endpoint results or secondary outcome results. It does not report means, standard deviations, treatment estimates, confidence intervals, p-values, or a statistical analysis plan. The listed serious-event percentages also lack an identified group attribution and denominator in the safety summary. These reporting gaps prevent evaluation of efficacy estimates, their precision, and a comparative safety profile.

The registry record does not report a sample-size justification, detailed eligibility criteria, or procedures for addressing possible differences between groups. The planning illustration is not the study’s own design justification and is not an observed-power analysis. These limitations should be kept distinct from findings: the record’s lack of outcome analyses means the comparative results cannot be assessed, rather than demonstrating that there was no effect.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Vashe Wound Therapy Study — NCT00586729.
• Registry record last updated 2012-09-14; status last verified 2012-09.
• Results first posted 2012-09-10.
• 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

NCT00586729, the Vashe Wound Therapy Study, is listed as completed and sponsored by Valleywise Health. The registry records enrollment of 23, a start date of 2009-07, and primary completion in 2010-11. The phase is listed as not applicable.

The parallel study used non-randomized allocation and no masking. It compared Vashe Wound Therapy with 5% Mafenide Acetate, each applied to gauze dressing every 6 hours or as needed to keep the dressing moist for a total treatment duration of 5 days. The primary endpoint was the percentage of grafted area viable at day 14, assessed in a per-protocol population. Length of stay and hospital cost per patient were listed as secondary outcomes.

The registry record lists three outcome measures and zero analyses. It does not report primary or secondary outcome results, the primary analysis sample size, or a treatment comparison. Serious and other adverse-event counts are recorded by group, while details needed for a fuller comparative safety interpretation are not reported.