This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Pilot RCT of Veraflo With Prontosan vs VAC in Wounds Requiring Operative Debridement (NCT01867580), a randomized na study. The primary outcome is Number of Inpatient Operating Room Debridements.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01867580 |
| Phase | NA |
| Condition | Wounds and Injuries |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 181 |
| Arms in the primary outcome | n/a |
| Lead sponsor | KCI USA, Inc |
| Results posted | Yes |
2. Clinical Question
Population
People with wounds requiring operative debridement. The primary outcome is specified for the per-protocol population, but further eligibility details are not reported in the registry record.
Intervention
V.A.C. Ulta with Prontosan instillation, described in the registry record as the treatment arm.
Comparator
V.A.C. Ulta without instillation, described as the control arm.
Primary question
How does the number of inpatient operating-room debridements compare between the treatment strategies, until the wound is deemed ready for closure or coverage by the investigator, up to 64 days?
The trial question is about the frequency of surgical debridement in the setting of wounds that have already undergone operative debridement. The registry defines debridement for this outcome as surgical removal of non-viable tissue performed in an operating room. The intervention contrast is the use of Prontosan instillation with the V.A.C. Ulta system versus the same named system without instillation.
The registry record also lists a secondary outcome concerning differences in total bacterial counts, measured in colony-forming units and determined by quantitative PCR analysis. That biological measurement is distinct from the primary clinical outcome: it concerns bacterial counts, whereas the primary outcome concerns inpatient operating-room debridements. The record does not report a primary-outcome effect estimate or enough detail to state how the recorded outcome categories compare between arms. It therefore supports describing the research question and its endpoint, but not a conclusion about the direction or size of the primary result.
3. Trial Design
NCT01867580 is listed as a randomized, parallel-group trial with no masking. The official title describes it as prospective and multicenter. Its two listed strategies are V.A.C. Ulta with Prontosan instillation and V.A.C. Ulta without instillation. The record labels these the treatment and control arms, respectively. The study status is completed, and the enrollment field reports 181.
The registry record gives a start of 2013-05 and primary completion of 2015-08. The phase is listed as NA. These administrative details describe the registered trial; they do not, by themselves, explain how participants were recruited, how allocation was concealed, or how the treatment was delivered at each center. Those details are not reported in the registry record.
Random allocation is intended, in general, to reduce systematic differences between treatment groups at the point of assignment. A parallel design means participants are assigned to a strategy and assessed within that group rather than crossing over between strategies. Because masking is listed as none, the record does not describe the trial as masked. It does not specify whether participants, treating clinicians, outcome assessors, or analysts were unmasked individually, so the scope of that label should not be extended beyond what the record states.
The primary endpoint is identified for the per-protocol population. The record does not report the details of that population definition, the number assessed for the primary outcome, or how participants who did not follow the assigned strategy were handled. The reason for the enrollment target, the planned statistical analysis, and any interim-analysis procedures are not reported in the registry record. The trial design information therefore establishes the broad comparison and structure, but does not provide a complete account of implementation or analysis.
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
| Stage | V.A.C.Ulta With Prontosan Instillation | V.A.C.Ulta Without Instillation |
|---|---|---|
| STARTED | 93 | 88 |
| COMPLETED | 65 | 64 |
| NOT COMPLETED | 28 | 24 |
Reasons for not completing this period:
| Reason | V.A.C.Ulta With Prontosan Instillation | V.A.C.Ulta Without Instillation |
|---|---|---|
| Withdrawal by Subject | 2 | 3 |
| Physician Decision | 17 | 12 |
| Lost to Follow-up | 3 | 5 |
| Sponsor terminated study | 1 | 0 |
| Missed follow-up assessment | 2 | 1 |
| Interruption to therapy | 3 | 0 |
| Osteomyelitis | 0 | 1 |
| Continuation of therapy | 0 | 1 |
| Wound recurrence | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Per-protocol population
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.
| Characteristic | Unit | V.A.C.Ulta With Prontosan Instillation | V.A.C.Ulta Without Instillation | Total |
|---|---|---|---|---|
| Participants analysed | 93 | 88 | 181 | |
| Age, Continuous | years | 53.0 (SD 13.92) | 52.0 (SD 14.25) | 53.0 (SD 14.04) |
| Sex: Female, Male: Female | Participants | 31 | 32 | 63 |
| Sex: Female, Male: Male | Participants | 62 | 56 | 118 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 20 | 14 | 34 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 73 | 74 | 147 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 34 | 34 | 68 |
| Race (NIH/OMB): White | Participants | 59 | 53 | 112 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 1 | 1 |
| Region of Enrollment: United States | Participants | 93 | 88 | 181 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Inpatient Operating Room Debridements, measured over until the wound is deemed ready for closure or coverage by the investigator up to 64 days.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is titled “Number of Inpatient Operating Room Debridements.” The registry specifies its unit as participants and describes the relevant procedure as surgical removal of non-viable tissue in an operating room. The assessment period continues until the investigator deems the wound ready for closure or coverage, up to 64 days. The specified analysis population is per protocol.
This outcome is intended to characterize the use of inpatient operating-room debridement during the stated wound-care period. In general, a count of procedures can reflect repeated procedures as well as whether a participant experienced any procedure. However, the record identifies this measure with participants as its unit and does not provide the outcome categories or a numerical distribution. It would therefore be inappropriate to assume how repeat procedures are represented or to reconstruct a count from the endpoint title alone.
The registry indicates that the primary outcome has several categories or time points and is not reduced to a single comparison. Consequently, the posted information does not support a simple arm-level effect estimate for this endpoint. The rationale for selecting this measure, the precise category definitions, and the analysis method are not reported in the registry record. The endpoint can be described, but its comparative result cannot be interpreted from the available primary-outcome details.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies the clinical comparison and names the primary endpoint, but the primary outcome information does not resolve into a single numerical contrast. The record states that the outcome has several categories or time points and is not reduced to one comparison. No primary-outcome effect estimate, uncertainty interval, or p-value is reported in the registry record. Accordingly, the available record does not establish the direction, magnitude, or precision of a difference in inpatient operating-room debridements between the treatment strategies.
The outcome title refers to the number of debridements, while the listed unit is participants. Without category-level results or definitions, it is not possible to tell how the measure represents participants with different procedure counts. This matters because a count outcome can be summarized in different ways, and those summaries answer different questions. A single average, a participant-level category comparison, and the proportion with any procedure are not interchangeable. The registry record does not permit choosing among these interpretations.
The record reports the analysis population as per protocol. In general, a per-protocol analysis focuses on participants meeting specified adherence or eligibility conditions, whereas an intention-to-treat analysis retains participants according to randomized assignment. Neither the exact per-protocol definition nor an intention-to-treat result is reported in the registry record. The primary-outcome population therefore needs to be kept in view when interpreting any result attributed to this endpoint.
The safety information is descriptive: it lists participants affected by serious and other adverse events in each arm, deaths, and selected serious adverse-event terms with percentages. These figures do not supply a randomized comparison adjusted for follow-up or other factors. The record does not report the methods used to collect, classify, or compare adverse events, nor does it provide uncertainty estimates for the listed percentages. The counts and terms can be described as registry safety information, but they should not be read as a definitive causal estimate.
Overall, the record supports a description of a randomized comparison, its endpoint, and selected safety counts. It does not support a firm estimate of the primary treatment contrast. The absence of a consolidated primary comparison is especially important: it is not evidence that the arms were the same, and it is not evidence that one strategy produced fewer procedures. It means that the registered outcome information available for interpretation does not provide that comparison.
9. Statistical Methods Explained
What does randomization contribute?
Randomization is a method for assigning participants to treatment groups by chance. As a general statistical principle, it aims to make treatment assignment independent of participants’ measured and unmeasured characteristics at baseline. This can reduce confounding in a comparison, provided that the randomization process is implemented and analyzed appropriately. The record identifies the trial as randomized, but details such as the sequence-generation method and allocation concealment are not reported in the registry record. The label alone cannot establish how well those procedures were carried out.
A parallel-group design compares outcomes across participants assigned to different strategies. The registry lists V.A.C. Ulta with Prontosan instillation and V.A.C. Ulta without instillation. It also lists masking as none. In general, masking can reduce the influence of expectations on treatment delivery, outcome assessment, or reporting. The record does not specify which people knew assignment or whether outcome assessors were masked, so the stated masking status should not be taken as a detailed account of every role.
How should the primary outcome be understood?
The primary outcome is named as the number of inpatient operating-room debridements, with participants as the unit. It is assessed until the investigator judges the wound ready for closure or coverage, up to 64 days. The registry defines debridement as surgical removal of non-viable tissue performed in an operating room. These details identify the clinical event and the assessment window. They do not specify the precise coding of the reported categories, how multiple procedures per participant are represented, or which statistical model was used.
In general, count data can have features that differ from continuous measurements. Counts are non-negative and may be concentrated at a small number of values. A count model may be considered when the analysis retains the number of events per participant. Over-dispersion occurs when the observed variability is larger than a model assumes; if ignored, standard errors can be too small and uncertainty can be understated. These are general considerations, not descriptions of the analysis used in this trial. The registry record does not report a model, a dispersion estimate, or the outcome distribution. It also classifies the outcome information as not reduced to a single comparison because there are several categories or time points, so a single count-model interpretation cannot be reconstructed from the record.
What do estimates and confidence intervals mean?
In general, an effect estimate describes the contrast between groups on a chosen outcome scale. Its meaning depends on how the outcome was defined and which population was analyzed. A confidence interval describes the statistical uncertainty around an estimate under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, but precision alone does not establish clinical importance or eliminate bias. The registry record does not report a consolidated primary-outcome estimate or interval, so those quantities cannot be interpreted for this endpoint.
A p-value, when reported, assesses compatibility between the observed data and a specified null model under the analysis assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. The primary-outcome p-value and the statistical test used are not reported in the registry record. No conclusion about statistical significance should be inferred from the endpoint description or from the presence of other trial information.
How should the safety counts be read?
The registry lists the number at risk and number affected for serious adverse events and other adverse events in each arm, along with deaths. These are useful descriptive counts. In general, the number affected is easier to interpret when the population at risk, observation period, event definitions, and completeness of reporting are clear. The listed at-risk counts do not by themselves disclose how long participants were followed or whether each event was counted once per participant or repeatedly. Those details are not reported in the registry record.
Comparing raw adverse-event counts requires caution. Differences in time under observation, missing safety information, or event ascertainment can affect the observed counts. A randomized assignment does not remove these concerns if follow-up and reporting differ. The record does not provide a method for adjusting the safety comparisons, nor does it give uncertainty intervals for the listed counts or percentages. The serious adverse-event terms and percentages should therefore be read as registry descriptions, not as adjusted comparative effects.
What do the planning assumptions establish?
The record describes planning illustrations based on fractions of the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It states that the illustration is not the trial’s own design and that count outcomes use a different sample-size convention from time-to-event outcomes. Such illustrations are general planning tools: they show how a hypothetical future study’s required size can vary with the effect targeted and assumptions chosen. They are not observed power and do not establish the probability that this completed trial detected an effect. The numerical planning outputs and the protocol’s sample-size justification are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies a primary outcome and lists secondary outcomes, including a measure of total bacterial counts determined by quantitative PCR analysis. It reports 3 outcome measures and 3 analyses. The record does not specify whether each analysis corresponds to a separate outcome, whether multiple comparisons were prespecified, or how the analysis accounted for testing more than one outcome, category, or time point. A multiplicity adjustment or hierarchical testing strategy is not reported in the registry record.
Multiplicity matters in general because testing several hypotheses can increase the chance of obtaining at least one apparently unusual result by chance. The appropriate response depends on the scientific aims and the prespecified analysis plan; no particular adjustment can be assumed. The primary outcome itself is reported as having several categories or time points and is not reduced to a single comparison, which further limits a direct interpretation of its statistical evidence.
The primary endpoint is assigned to the per-protocol population. The criteria defining that population, the number of participants included in each outcome analysis, and any reasons for exclusion are not reported in the registry record. An intention-to-treat analysis is not reported. Missing-outcome counts, missing-data patterns, imputation procedures, and sensitivity analyses are also not reported in the registry record.
In general, missingness can affect an estimate when the availability of outcome data is related to treatment assignment or to the outcome itself. The extent of that concern cannot be judged without information on follow-up and missing data. The completed status and overall enrollment do not establish how many participants contributed to the primary analysis, particularly because its population is per protocol. These omissions prevent assessment of the analysis population’s completeness and of the robustness of results to alternative missing-data assumptions.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| V.A.C.Ulta With Prontosan Instillation | 19 | 93 | 20.4% |
| V.A.C.Ulta Without Instillation | 22 | 88 | 25.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| V.A.C.Ulta With Prontosan Instillation | 3 of 93 |
| V.A.C.Ulta Without Instillation | 1 of 88 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| V.A.C.Ulta With Prontosan Instillation | 58 of 93 |
| V.A.C.Ulta Without Instillation | 44 of 88 |
Most frequent serious adverse event terms
| Event term | Organ system | V.A.C.Ulta With Prontosan Instillation | V.A.C.Ulta Without Instillation |
|---|---|---|---|
| Osteomyelitis | Infections and infestations | 2 of 93 | 3 of 88 |
| Transplant Failure | Injury, poisoning and procedural complications | 3 of 93 | 2 of 88 |
| Wound Dehiscence | Injury, poisoning and procedural complications | 2 of 93 | 3 of 88 |
| Wound infection | Infections and infestations | 1 of 93 | 3 of 88 |
| Wound complication | Injury, poisoning and procedural complications | 0 of 93 | 4 of 88 |
| Cellulitis | Infections and infestations | 1 of 93 | 2 of 88 |
| Sepsis | Infections and infestations | 2 of 93 | 0 of 88 |
| Wound infection Staphylococcal | Infections and infestations | 1 of 93 | 1 of 88 |
| Phlebothrombosis | Vascular disorders | 1 of 93 | 1 of 88 |
| Wound Haemorrhage | Vascular disorders | 1 of 93 | 1 of 88 |
Most frequent non-serious adverse event terms
| Event term | Organ system | V.A.C.Ulta With Prontosan Instillation | V.A.C.Ulta Without Instillation |
|---|---|---|---|
| Skin Maceration | Skin and subcutaneous tissue disorders | 30 of 93 | 17 of 88 |
| Wound Dehiscence | Injury, poisoning and procedural complications | 26 of 93 | 15 of 88 |
| Oedema | General disorders | 14 of 93 | 8 of 88 |
| Wound Complication | Injury, poisoning and procedural complications | 10 of 93 | 7 of 88 |
| Pain | General disorders | 6 of 93 | 3 of 88 |
| Glycosylated Haemoglobin Increased | Investigations | 4 of 93 | 5 of 88 |
| Constipation | Gastrointestinal disorders | 1 of 93 | 7 of 88 |
| White Blood Cell Count Increased | Investigations | 5 of 93 | 2 of 88 |
Serious events with the highest arm-level rate: wound complication (4.5%), osteomyelitis (3.4%), wound infection (3.4%), wound dehiscence (3.4%), transplant failure (3.2%).
For V.A.C. Ulta with Prontosan instillation, the registry lists 93 participants at risk for serious adverse events and 19 affected. For V.A.C. Ulta without instillation, it lists 88 at risk and 22 affected. The listed deaths are 3 and 1, respectively. The registry also lists 93 and 88 at risk for other adverse events, with 58 and 44 affected, respectively. These figures are descriptive counts; they are not adjusted comparative estimates.
The serious adverse-event terms with listed percentages are Wound complication at 4.5%, Osteomyelitis at 3.4%, Wound infection at 3.4%, Wound Dehiscence at 3.4%, Transplant Failure at 3.2%, and Cellulitis at 2.3%. The record does not state the denominator or observation period used for these term-specific percentages, or whether a participant could contribute to more than one term. They should not be interpreted as mutually exclusive categories or compared across arms without that context.
In general, safety counts depend on event definitions, ascertainment, and the time each participant was observed. The registry does not report those details or uncertainty estimates for these figures. The counts describe what is listed; they do not alone establish that a treatment caused an event or that one arm had a higher underlying risk.
12. What the Result Does, and Does Not, Mean
The record establishes that the study was designed as a randomized comparison of V.A.C. Ulta with Prontosan instillation against V.A.C. Ulta without instillation in wounds requiring operative debridement. It identifies inpatient operating-room debridements as the primary outcome, describes the assessment period, and specifies a per-protocol analysis population. It also lists selected safety counts and a bacterial-count secondary outcome.
What the record does not establish is the size or direction of the primary-outcome difference. The endpoint is not presented as a single comparison, and the numerical outcome categories, effect estimate, uncertainty interval, and p-value are not reported in the registry record. Thus, the available record cannot support a statement that one strategy led to more or fewer debridements, nor can it establish that the strategies had similar outcomes.
Absence of a reported comparison is not the same as a finding of no difference. Likewise, the existence of a randomized design does not supply the missing estimate or guarantee that every possible source of bias was controlled. To assess the strength of a comparative conclusion, readers would need interpretable outcome results, a clear analysis population, and information on uncertainty and missing data.
The adverse-event figures provide descriptive safety information, but they are not a complete causal assessment. The registry does not report follow-up exposure, event definitions, or comparative uncertainty for those counts. The serious adverse-event term percentages also lack a stated denominator in the record. They can be reported as listed, but should not be treated as rates with a known basis or as proof of treatment attribution.
The most defensible interpretation is therefore limited: this is a completed randomized trial with a stated comparison and clinically relevant endpoint, but the registry information available for the primary endpoint is insufficient for a quantitative efficacy conclusion. The safety entries can be described, with the limitations of their reporting kept explicit.
13. Why This Trial Matters Statistically
This trial raises a useful statistical issue: a clearly named primary endpoint is not necessarily an interpretable treatment comparison. The registry specifies inpatient operating-room debridements, the participant-level unit, an assessment period ending when the investigator deems the wound ready for closure or coverage, and the per-protocol population. Yet it also states that the primary outcome has several categories or time points and is not reduced to one comparison. Without category-level results or an estimate on a defined scale, the endpoint cannot yield a clear summary of the randomized contrast.
The distinction between naming an outcome and reporting an estimand is important. An estimand is the precise treatment contrast the analysis aims to quantify, including the population, outcome, time period, and handling of events such as deviations or missing observations. General statistical interpretation depends on those choices. The registry record gives some of these ingredients but does not report the full analysis specification or a consolidated result.
The record also illustrates why safety counts need context. Counts affected and numbers at risk are useful descriptions, but they do not convey follow-up duration, completeness, or uncertainty. Term-specific percentages without a stated denominator are particularly difficult to compare. Clear reporting of event definitions and analytic methods would help readers distinguish descriptive surveillance from a comparative safety estimate.
Finally, planning illustrations based on an observed effect should not be mistaken for the trial’s original design justification or for observed power. The record explicitly characterizes these calculations as illustrations rather than the trial’s own design. Keeping planning assumptions separate from observed results helps prevent a common interpretive error: treating retrospective sample-size calculations as evidence that a study was adequately powered or that a null result is conclusive.
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-outcome reporting is the central limitation for interpretation. The registry says that the endpoint has several categories or time points and is not reduced to a single comparison. It does not provide category-level results, a consolidated effect estimate, a confidence interval, or a p-value. As a result, the primary endpoint cannot be used from this record to quantify the treatment contrast.
The endpoint description leaves important details unresolved. The outcome title refers to a number of debridements, while the unit is participants. The registry does not explain how multiple debridements are represented, define the outcome categories, or report the statistical method. The assessment period is given, but the underlying outcome values are not available in the registry record for interpretation.
The primary population is per protocol, but its definition and the number analyzed are not reported. The record does not provide participant flow, adherence information, missing-data counts, handling of missing outcomes, or an intention-to-treat result. Those omissions limit assessment of selection after randomization and robustness to missing information. Allocation concealment, randomization procedures, and the roles covered by the unmasked status are also not reported in the registry record.
Safety reporting is limited to counts and selected terms with percentages. The record does not state the observation duration, detailed event definitions, denominator for each term-specific percentage, or method for comparative analysis. The secondary bacterial-count outcome is named, but its results and analysis details are not reported in the registry record. Multiplicity procedures and the protocol’s sample-size rationale are also not reported. These limitations constrain both statistical and clinical interpretation without implying that any unreported procedure was or was not performed.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Pilot RCT of Veraflo With Prontosan vs VAC in Wounds Requiring Operative Debridement — NCT01867580.
- Registry record last updated 2024-12-02; status last verified 2024-11.
- Results first posted 2017-11-29.
- 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.
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18. Record Summary
NCT01867580 is a completed randomized, unmasked, parallel trial described as prospective and multicenter. It compares V.A.C. Ulta with Prontosan instillation against V.A.C. Ulta without instillation in wounds requiring operative debridement. The registry lists enrollment of 181, a start of 2013-05, and primary completion of 2015-08. The sponsor is KCI USA, Inc.
The primary outcome is the number of inpatient operating-room debridements, assessed until the investigator deems the wound ready for closure or coverage, up to 64 days, in the per-protocol population. The registry does not reduce its several categories or time points to one comparison. A secondary outcome concerns total bacterial counts measured in colony-forming units by quantitative PCR analysis.
Safety entries list serious and other adverse events, deaths, and selected serious adverse-event terms. The record does not report a consolidated primary-outcome estimate or the analysis details needed to interpret it quantitatively. Trial implementation details, missing-data methods, and multiplicity procedures are not reported in the registry record.