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 Evaluation of the Use of EZCare/V1STA in the Management of Acute and Chronic Wounds (NCT00994162), a na na study. The primary outcome is Number of Wounds Stratified by Wound Area for the Performance of EZCare/V1STA in Terms of Wound Progress Towards Closure in Wounds Deemed Suitable for Treatment With Negative Pressure Wound Therapy (NPWT) - Wound Area (Baseline Measurements).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00994162 |
| Phase | NA |
| Condition | Wounds |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 153 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Smith & Nephew, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The evaluation concerns wounds considered suitable for negative pressure wound therapy. The record describes acute and chronic wounds and notes that baseline data were divided into grafted and non-grafted wound-site subgroups. It reports 153 enrolled participants and says that baseline data represent enrolled subjects present at that time, as provided by each site.
Intervention
The intervention was the EZCare/V1STA Negative Pressure Wound Therapy System, described as application of negative pressure wound therapy to the wound. The stated aim was to assess the products’ performance across different clinical environments and wound types.
Comparator
The registry describes a single-group evaluation, with no like-for-like control group. Allocation is listed as NA, and the evaluation is open-labelled with no masking. The grafted and non-grafted subgroups describe wound types; they are not identified as treatment and control groups.
Primary question
The primary outcome concerns the number of wounds stratified by wound area at baseline. The broader stated objective was to assess wound progression toward closure using measures that included wound area, volume, depth, granulation tissue formation, and exudate management. However, the listed primary measure is specifically a baseline wound-area count. Numerical baseline area results and subsequent changes are not reported in the registry record.
3. Trial Design
The registry describes a prospective, open-labelled, multicentre evaluation of the EZCare/V1STA negative pressure wound therapy system. Its official title identifies acute and chronic wounds as the clinical setting. The study is marked completed, and its phase is listed as NA. The recorded start is 2008-04, with primary completion in 2009-01. The sponsor is Smith & Nephew, Inc.
The design is listed as single-group, with allocation recorded as NA and masking recorded as NONE. The intervention description is application of negative pressure wound therapy to the wound. No separate comparator group is described. The registry explicitly cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison. The listed grafted and non-grafted subgroups characterize wound sites; they do not create a randomized treatment contrast.
Enrollment is reported as 153 participants. The primary outcome describes wounds, rather than participants, stratified by wound area at baseline. The record says that baseline data represent enrolled subjects present at baseline as provided by the site. This distinction matters: a participant count does not establish the number of wounds measured, and the registry record does not give wound-level denominators or the distribution of wounds across the subgroups.
The outcome list also covers performance characteristics such as ease of application and removal, wear time, dressing-change time, pain, and odor. These are listed as secondary outcomes, but numerical results and analytic details for them are not reported in the registry record. A prospective design means observations were planned going forward; it does not by itself establish a control group, masking, or a particular analysis method.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: A total of 153 subjects were enrolled; however, one V1STA subject was withdrawn from the study due to medical complications that prohibited the application of the NPWT system. The subject was excluded from the full analysis set (FAS) population, but included in the safety (SAF) population.
Overall Study
| Stage | Negative Pressure Wound Therapy |
|---|---|
| STARTED | 153 |
| Participants Receiving Treatment | 152 |
| COMPLETED | 125 |
| NOT COMPLETED | 28 |
Reasons for not completing this period:
| Reason | Negative Pressure Wound Therapy |
|---|---|
| Withdrawal by Subject | 1 |
| Lost to Follow-up | 2 |
| Product Complaint | 1 |
| Poor Compliance | 5 |
| Lack of Response | 3 |
| Discharged from Hospital | 4 |
| Death | 2 |
| Care Transferred to Another Physician | 2 |
| Discontinued and Changed to Iodoflex | 1 |
| Physician Decision | 2 |
| Surrounding Wound Erythematous | 1 |
| Machine Losing Vaccum | 1 |
Analysis population for the primary outcome, as defined in the registry: The study was further divided into subgroups of subjects with a grafted wound site or subjects with a non-grafted wound site to compare wound types. The data presented represent the enrolled subjects present at Baseline as provided by the site.
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.
Population: The decision to report the 2 studies with a single CSR was due to high levels of similarity in both the study designs and the products themselves; the individual study designs were largely similar with the same patient population criteria, study endpoints, and data capture requirements; and the products were identical in terms of their indications for use and therapeutic delivery of NPWT.
| Characteristic | Unit | NPWT (Non-Grafted Sites) | NPWT (Grafted Sites) | Total |
|---|---|---|---|---|
| Participants analysed | 131 | 21 | 152 | |
| Age, Continuous | years of age | 60.5 (SD 16.8) | 43.2 (SD 16.2) | 58.0 (SD 17.8) |
| Sex: Female, Male: Female | Participants | 61 | 5 | 66 |
| Sex: Female, Male: Male | Participants | 69 | 16 | 85 |
| Treatment Setting: Long-term care/nursing home | Participants | 3 | 0 | 3 |
| Treatment Setting: Home | Participants | 29 | 2 | 31 |
| Treatment Setting: Hospital | Participants | 76 | 19 | 95 |
| Treatment Setting: Wound Clinic | Participants | 23 | 0 | 23 |
| Patient Mobility: Walks Unaided | Participants | 50 | 12 | 62 |
| Patient Mobility: Walks with Aid | Participants | 30 | 5 | 35 |
| Patient Mobility: Walks Unaided/Walks with Aid | Participants | 0 | 1 | 1 |
| Patient Mobility: Chair Bound | Participants | 16 | 2 | 18 |
| Patient Mobility: Walks with Aid/Chair Bound | Participants | 1 | 0 | 1 |
| Patient Mobility: Bed Bound | Participants | 31 | 1 | 32 |
| Patient Mobility: Chair Bound/Bed Bound | Participants | 3 | 0 | 3 |
| Medical History: Anemia – Current condition | Participants | 8 | 0 | 8 |
| Medical History: Anemia – Prior condition | Participants | 3 | 0 | 3 |
| Medical History: Anemia – Had condition, current/prior not given | Participants | 4 | 1 | 5 |
| Medical History: Anemia – Never had the condition | Participants | 116 | 20 | 136 |
| Medical History: Diabetes – Current condition | Participants | 26 | 4 | 30 |
| Medical History: Diabetes – Prior condition | Participants | 2 | 0 | 2 |
| Medical History: Diabetes – Had condition, current/prior not given | Participants | 23 | 1 | 24 |
| Medical History: Diabetes – Never had the condition | Participants | 80 | 16 | 96 |
| Medical History: Stroke/cardiovascular accident (CVA) – Current condition | Participants | 3 | 0 | 3 |
| Medical History: Stroke/cardiovascular accident (CVA) – Prior condition | Participants | 7 | 0 | 7 |
| Medical History: Stroke/cardiovascular accident (CVA) – Had condition, current/prior not given | Participants | 7 | 0 | 7 |
| Medical History: Stroke/cardiovascular accident (CVA) – Never had the condition | Participants | 114 | 21 | 135 |
| Medical History: Hypertension – Current condition | Participants | 29 | 2 | 31 |
| Medical History: Hypertension – Prior condition | Participants | 2 | 0 | 2 |
| Medical History: Hypertension – Had condition, current/prior not given | Participants | 27 | 1 | 28 |
| Medical History: Hypertension – Never had the condition | Participants | 73 | 18 | 91 |
| Medical History: Peripheral vascular disease – Current condition | Participants | 11 | 0 | 11 |
| Medical History: Peripheral vascular disease – Prior condition | Participants | 1 | 0 | 1 |
| Medical History: Peripheral vascular disease – Had condition, current/prior not given | Participants | 17 | 1 | 18 |
| Medical History: Peripheral vascular disease – Never had the condition | Participants | 102 | 20 | 122 |
| Medical History: Congestive heart failure – Current condition | Participants | 4 | 0 | 4 |
| Medical History: Congestive heart failure – Prior condition | Participants | 2 | 1 | 3 |
| Medical History: Congestive heart failure – Had condition, current/prior not given | Participants | 6 | 0 | 6 |
| Medical History: Congestive heart failure – Never had the condition | Participants | 119 | 20 | 139 |
| Medical History: Rheumatoid arthritis – Current condition | Participants | 2 | 0 | 2 |
| Medical History: Rheumatoid arthritis – Prior condition | Participants | 0 | 0 | 0 |
| Medical History: Rheumatoid arthritis – Had condition, current/prior not given | Participants | 5 | 0 | 5 |
| Medical History: Rheumatoid arthritis – Never had the condition | Participants | 124 | 21 | 145 |
| Medical History: Osteoarthritis – Current condition | Participants | 3 | 0 | 3 |
| Medical History: Osteoarthritis – Prior condition | Participants | 0 | 0 | 0 |
| Medical History: Osteoarthritis – Had condition, current/prior not given | Participants | 16 | 0 | 16 |
| Medical History: Osteoarthritis – Never had the condition | Participants | 112 | 21 | 133 |
| Medical History: Deep vein thrombosis (DVT) – Current condition | Participants | 1 | 0 | 1 |
| Medical History: Deep vein thrombosis (DVT) – Prior condition | Participants | 1 | 0 | 1 |
| Medical History: Deep vein thrombosis (DVT) – Had condition, current/prior not given | Participants | 0 | 0 | 0 |
| Medical History: Deep vein thrombosis (DVT) – Never had the condition | Participants | 129 | 21 | 150 |
| Medical History: Varicose veins – Current condition | Participants | 2 | 0 | 2 |
| Medical History: Varicose veins – Prior condition | Participants | 1 | 0 | 1 |
| Medical History: Varicose veins – Had condition, current/prior not given | Participants | 2 | 1 | 3 |
| Medical History: Varicose veins – Never had the condition | Participants | 126 | 20 | 146 |
| Wound Type: Surgical wound | Participants | 63 | 0 | 63 |
| Wound Type: Traumatic wound | Participants | 12 | 0 | 12 |
| Wound Type: Pressure ulcer | Participants | 34 | 0 | 34 |
| Wound Type: Diabetic foot ulcer | Participants | 15 | 0 | 15 |
| Wound Type: Leg ulcer | Participants | 4 | 0 | 4 |
| Wound Type: Graft site | Participants | 0 | 21 | 21 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Wounds Stratified by Wound Area for the Performance of EZCare/V1STA in Terms of Wound Progress Towards Closure in Wounds Deemed Suitable for Treatment With Negative Pressure Wound Therapy (NPWT) - Wound Area (Baseline Measurements), measured over Baseline.
| Element | Registry entry |
|---|---|
| Result type | Count Of Units |
| Measure of spread | not applicable |
| Unit | Wounds |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is the number of wounds stratified by wound area at baseline. It is a count-based description of wounds in area categories, not a direct estimate of treatment effect. The broader outcome description says that wound area, volume, and depth, alongside granulation tissue and exudate management, were considered in assessing progression toward closure. Yet the named primary measure is specifically the baseline wound-area measure.
A baseline assessment can describe the wounds entering evaluation and provide a starting point for later measurements. In a longitudinal assessment, changes from baseline may help describe how wound characteristics evolve during treatment. A baseline count alone cannot show such change, because it does not compare a later measurement with the starting measurement. Nor can it distinguish treatment-associated change from other influences without a suitable comparison and an analysis designed to address that question.
The record identifies grafted and non-grafted wound-site subgroups and says the primary data represent enrolled subjects present at baseline, as posted by sites in the registry description. It does not report the numerical area categories, wound counts within those categories, area summary statistics, or follow-up changes. The primary measure therefore identifies what was intended to be tabulated, but the registry record does not supply the values needed to assess the distribution of baseline wound area or progression toward closure.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the broad design and the type of primary outcome, but it does not report numerical results for the baseline wound-area measure. It also does not provide an estimated change in wound area, a comparison with an untreated or alternative-treatment group, or an effect estimate with a confidence interval. Consequently, the available record cannot quantify wound progression or the precision of an estimated treatment effect.
The outcome title refers to wound progress toward closure, while its stated timeframe is baseline. These are different kinds of information. Baseline wound area describes starting characteristics; evidence of progression requires measurements across time and an analysis of change. The record’s broader description mentions assessment of area, volume, depth, granulation tissue, and exudate management, but does not provide the corresponding numerical findings in the registry record for interpretation. The listed baseline endpoint alone should not be read as a result about subsequent healing.
The evaluation has a single-group, open-label design, with no randomized comparison identified. Observations made during treatment can describe the experience of the evaluated group, but without a suitable comparator they cannot isolate the effect of the device from other possible explanations for change. Open-label status also means that masking is not part of the recorded design. The record does not provide enough detail to determine how subjective outcomes, such as pain or ease of application, were collected or assessed.
The registry lists 153 enrolled participants, but the primary outcome is expressed as a count of wounds. The participant enrollment figure should not be treated as the denominator for wound-area categories unless the record explicitly establishes that correspondence; it does not do so. The number of wounds measured, their distribution across grafted and non-grafted subgroups, and the number with later measurements are not reported in the registry record.
The record lists no analysis entries. It does not report an analysis plan, inferential results, confidence intervals, p-values, or methods for handling missing observations. These omissions prevent assessment of the statistical uncertainty around any outcome and of whether the analysis followed a prespecified plan. In particular, the data described do not support conclusions about a comparative benefit, a causal effect, or the extent of change in wound characteristics. The appropriate reading is limited to the evaluation’s stated purpose, design, and outcome definitions, with the numerical outcome findings not reported in the registry record.
9. Statistical Methods Explained
The registry describes a prospective, open-labelled, multicentre, single-group evaluation. It does not report statistical methods for the primary outcome. The explanations below are general statistical context, not a description of analyses confirmed to have been performed in this evaluation.
What does a count outcome describe?
A count outcome records how many observational units fall into a category or meet a definition. For this evaluation, the primary outcome is framed as the number of wounds stratified by wound area at baseline. Counts can describe the composition of a group, but their interpretation depends on the unit counted, the categories used, and the denominator. A participant count and a wound count are not interchangeable: a participant may be associated with more than one wound, and the record does not specify the number of wounds measured. The wound-area categories and their numerical counts are not reported in the registry record.
Counts may also be summarized as proportions or rates, but those summaries require clearly defined denominators and, for rates, a relevant exposure period. Such quantities cannot be reconstructed without the underlying data and definitions. The registry record’s enrollment figure does not by itself supply a wound-level denominator.
Why distinguish baseline description from change?
A baseline measurement describes the starting state. To describe change, an analysis needs measurements at later time points and a defined comparison with baseline. A simple change score is one possible descriptive approach, while repeated-measures models can account for measurements collected over time. Those approaches answer different questions and depend on how measurements are distributed and how missing observations are handled. The record names baseline as the timeframe for the primary wound-area outcome and does not report later wound-area results or a method for analyzing change.
The outcome description mentions wound progression and measures including area, volume, and depth. Those aims do not establish that all measures were analyzed, how they were summarized, or what timing and measurement procedures were used. The statistical analysis details are not reported in the registry record.
What does a single-group design allow?
A single-group evaluation can describe outcomes observed among participants receiving the intervention. In general, a before-and-after pattern within a group is not equivalent to a randomized treatment contrast. Changes over time may reflect several influences, and the design does not provide a concurrent randomized control group to separate those influences. Here, allocation is listed as NA and the registry flags the study as not a randomized comparison. The grafted and non-grafted wound-site subgroups are descriptions of wound types, not evidence of randomized assignment.
Open-label status indicates that masking was not used according to the registry. This is particularly relevant when outcomes involve judgments or reports, such as pain, odor, or ease of dressing application and removal. General methods to reduce measurement bias include consistent assessment procedures and independent assessment, but whether any such procedures were used is not reported in the registry record.
Why can wounds within a participant matter?
When multiple observations come from the same participant, those observations may be related. Standard analyses that assume every wound is independent can understate uncertainty if within-participant correlation is ignored. General approaches can account for clustering, for example by modeling participant-level dependence or using participant-clustered uncertainty estimates. The registry record does not report how many wounds were measured per participant or whether any analysis accounted for clustering. It also does not report the number of participating sites or a method for accounting for site-level variation, despite describing the evaluation as multicentre.
What would uncertainty measures mean?
A confidence interval is a general way to express statistical uncertainty around an estimate. A narrow interval indicates greater precision under the assumptions of the analysis; a wide interval indicates less precision. A p-value, when used, describes how compatible data are with a specified null model under its assumptions. Neither measure substitutes for the estimate itself, and neither establishes clinical importance. No confidence intervals, p-values, or numerical estimates for the primary outcome are reported in the registry record.
Over-dispersion is a general issue for count data. It occurs when observed variability exceeds what a chosen count model assumes. If present and ignored, model-based uncertainty can be too small. Model choice depends on the data and on the question being asked; the record does not identify a count model or report diagnostics. It is therefore not possible to assess whether over-dispersion was relevant or how it was handled.
What do the listed planning illustrations establish?
Sample-size calculations are planning tools, not observed outcomes or evidence that a study had adequate precision. The stated illustration assumptions refer to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the detectable effect expressed as a fraction of an observed effect. The stated illustration is not the trial’s own design. This evaluation is described as single-group, and the numerical effect estimates needed to interpret any planning illustration are not reported in the registry record. Such calculations should not be read as observed power or as evidence that a treatment effect was demonstrated.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 11 outcome measures. The secondary outcomes include ease of application and removal, wear time, dressing-change time, wound pain, and odor. The primary outcome concerns baseline wound area. Considering several outcomes can create a multiplicity issue: when many statistical tests are performed, the chance of at least one apparently unusual result can increase. General approaches include prespecifying a primary hypothesis, adjusting for multiple tests, or treating secondary analyses as exploratory. The registry record does not report a multiplicity strategy, a hierarchy of hypotheses, or which outcomes were included in any inferential analysis.
Missing-data methods are also not reported in the registry record. The primary outcome description says that the baseline data represent enrolled subjects present at baseline, as provided by the site. This wording does not establish how many enrolled participants or wounds lacked measurements, why any data were absent, or whether missingness was handled by exclusion, imputation, or another approach. The record does not report follow-up completeness for later outcome measures.
The analysis population is not defined beyond the baseline description. In general, a clear analysis population specifies which participants or observations are included and how protocol deviations or incomplete measurements are treated. The registry record does not describe an intention-to-treat population, an evaluable population, or a wound-level inclusion rule. Because the outcome counts wounds while enrollment counts participants, the absence of a reported unit-specific denominator is important when interpreting summaries.
These gaps limit assessment of robustness. Without details on multiplicity, missingness, and analysis populations, readers cannot determine whether reported findings, if any, reflect all eligible observations or a selected subset. Numerical outcome results and these methodological details are not reported in the registry record.
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 |
|---|---|---|---|
| Negative Pressure Wound Therapy | 2 | 153 | 1.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Negative Pressure Wound Therapy | 2 of 153 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Negative Pressure Wound Therapy | 1 of 153 |
Most frequent serious adverse event terms
| Event term | Organ system | Negative Pressure Wound Therapy |
|---|---|---|
| Natural Causes | General disorders | 1 of 153 |
| Alcoholic Liver Disease | Hepatobiliary disorders | 1 of 153 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Negative Pressure Wound Therapy |
|---|---|---|
| Peri-wound maceration and inflammation | Skin and subcutaneous tissue disorders | 1 of 153 |
Serious events with the highest arm-level rate: natural causes (0.7%), alcoholic liver disease (0.7%).
For the Negative Pressure Wound Therapy group, the registry reports 153 participants at risk for serious adverse events and 2 participants affected. It also reports 153 at risk for other adverse events and 1 affected. The listed death count is 2. These are registry counts; they should not be treated as evidence that the intervention caused an event or death. The record details reproduced do not establish event timing, individual circumstances, or causal attribution.
The registry lists Natural Causes and Alcoholic Liver Disease among the leading serious-event terms, each reported as 0.7%. These percentages should be read as the registry’s reported figures, not independently reconstructed rates. The available record does not explain the relationship between these terms and the death count, whether event terms overlap, or how seriousness and attribution were adjudicated.
Safety counts need context, including the definitions used, observation period, completeness of reporting, and whether events were considered related to the intervention. Those details are not reported in the registry record. The counts therefore describe what the registry records for this group; they do not by themselves establish comparative safety or a causal relationship.
12. What the Result Does, and Does Not, Mean
The record identifies an evaluation of EZCare/V1STA negative pressure wound therapy in acute and chronic wounds and specifies a baseline wound-area outcome. It also describes additional performance and wound-related outcomes. These details clarify the intended scope of the evaluation, but the numerical findings for the primary wound-area outcome are not reported in the registry record.
The primary outcome’s baseline timeframe is important. A count of wounds by area at the start can characterize the evaluated wounds, but it cannot show whether area subsequently decreased, whether wounds progressed toward closure, or how quickly any change occurred. The outcome description refers to broader healing-related assessments, but the corresponding numerical results and follow-up comparisons are not reported in the registry record.
The design is single-group, open-label, and nonrandomized. It can describe observations within the treated group, but it does not provide a randomized comparison that would distinguish treatment effects from other possible explanations. The presence of grafted and non-grafted wound-site subgroups does not change this design limitation: the record describes these as wound-type subgroups, not as randomized treatment groups.
Enrollment is reported as 153 participants, while the primary endpoint counts wounds. The registry record does not report the wound-level totals or category counts needed to interpret that outcome. It also does not report an analysis, uncertainty estimates, or methods for handling missing data and multiple outcomes. As a result, the direction, magnitude, and precision of any treatment-associated change cannot be determined from the record.
The safety entries record serious adverse events, other adverse events, and deaths in the intervention group. Without information on causality, timing, event definitions, and a comparison group, those counts cannot establish whether the intervention increased or decreased risk. Overall, the record describes what the evaluation set out to assess and some safety counts, but it does not establish a comparative effect, a causal conclusion, or a numerical estimate of wound healing.
13. Why This Trial Matters Statistically
This evaluation is statistically instructive because its stated clinical aim and its named primary measure operate on different levels. The aim concerns wound progression, while the primary outcome is a count of wounds stratified by area at baseline. Baseline characterization can be useful, but it is not itself evidence of longitudinal progress. Keeping the measurement timepoint explicit prevents a descriptive starting profile from being mistaken for a treatment outcome.
The record also highlights the distinction between participants and wounds. Enrollment is reported for participants, whereas the primary measure counts wounds. If a participant can contribute multiple wounds, those observations may be statistically related. Interpreting wound-level counts therefore requires clarity about denominators and about any dependence between observations. The registry record does not provide these details, so the distinction itself is a central consideration.
Design matters as much as the outcome definition. This is a single-group, open-label evaluation, not a randomized comparison. The design can describe the group’s experience but cannot, by itself, separate treatment effects from other influences over time. Grafted and non-grafted subgroups may help describe different wound types, but they do not provide a randomized control contrast.
Finally, the record illustrates why outcome definitions, analysis methods, and results all matter for interpretation. It lists a range of outcomes but does not report an analysis plan, numerical primary results, uncertainty estimates, missing-data methods, or multiplicity handling. Without these elements, readers cannot assess the precision or robustness of an estimated effect. The statistical lesson is not a conclusion about the device; it is the need to align the clinical question, unit of analysis, measurement timing, study design, and reported results.
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 main limitation for statistical interpretation is that numerical results for the primary outcome are not reported in the registry record. The endpoint is a baseline count of wounds stratified by area, but the area categories, counts, and subgroup results are absent. The broader outcome description mentions wound progression and other wound characteristics, yet later measurements and changes from baseline are not reported.
The single-group design has no randomized comparator. Observed patterns during treatment therefore cannot be attributed to the device alone on the basis of this design. The open-label format also leaves potential for assessment or reporting effects, particularly for outcomes involving pain, odor, and ease of application or removal; the record does not describe methods intended to address these concerns.
The participant enrollment figure does not resolve the wound-level denominator for the primary outcome. The number of wounds per participant, the number measured, and whether analyses account for possible within-participant dependence are not reported in the registry record. Although the evaluation is described as multicentre, the record does not give site-level results or describe any method for accounting for site variation.
Other important details are also absent: numerical follow-up results, analysis methods, confidence intervals, p-values, missing-data procedures, analysis-population definitions, and multiplicity handling. The record does not report a sample-size justification for the study’s own design. Safety counts are listed, but event timing, attribution, and adjudication details are not reported. These limitations prevent a quantitative assessment of treatment effect, precision, and robustness.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation of the Use of EZCare/V1STA in the Management of Acute and Chronic Wounds — NCT00994162.
- Registry record last updated 2022-09-21; status last verified 2020-03.
- Results first posted 2022-09-21.
- 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
NCT00994162 is a completed, prospective, open-labelled, multicentre, single-group evaluation of the EZCare/V1STA Negative Pressure Wound Therapy System for acute and chronic wounds. The registry lists 153 enrolled participants, allocation as NA, masking as NONE, and phase as NA. The recorded start is 2008-04 and primary completion is 2009-01; the sponsor is Smith & Nephew, Inc.
The primary outcome is the number of wounds stratified by wound area at baseline, with grafted and non-grafted wound-site subgroups described. The record also lists outcomes concerning device performance and wound characteristics. Numerical primary outcome results and analysis entries are not reported in the registry record. The safety record lists 2 participants affected by serious adverse events, 1 affected by other adverse events, and 2 deaths in the group.