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 An Evaluation of a Collagen Dressing to Treat Chronic, Stalled Lower-extremity Wounds (NCT03723603), a na na study. The primary outcome is Change in Wound Size Over Twelve Week Period.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03723603 |
| Phase | NA |
| Condition | Wound |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Medline Industries |
| Results posted | Yes |
2. Clinical Question
Population
Patients meeting the study’s inclusion criteria who had chronic, stalled lower-extremity wounds. The registry lists an enrollment of 8, but does not report how many participants contributed data to an outcome analysis.
Intervention
Fibrillar collagen powder dressing, applied to the wound after cleansing and covered with an appropriate moisture-retentive secondary dressing. The registry describes reapplication at clinic visits twice a week, with wound evaluations once a week.
Comparator
There was no comparison group: the design is single-group, and allocation is listed as NA. Concurrent standard of care could be provided, including compression for venous ulcers, but this is not described as a control arm.
Primary question
The planned primary question was how wound size changed from baseline to 84 days during treatment. The study was terminated prematurely, and the registry states that the data were not assessed. It therefore does not report an estimate of wound-size change or a comparison that could establish whether the dressing caused a change.
This case series was registered as an evaluation of a fibrillar collagen powder dressing for chronic, stalled lower-extremity wounds. Its design can describe an experience with the dressing in the enrolled group, but it cannot separate an intervention effect from other influences on wound size. In particular, concurrent standard of care was allowed, and there was no like-for-like control group. The registry identifies change in Bates-Jensen Wound Assessment Tool and change in reported pain level as secondary outcomes, but does not report their results. The central interpretive fact is that the primary data were not assessed after premature termination. The clinical question was planned, but the registry record does not supply an outcome estimate with which to answer it.
3. Trial Design
The registry identifies NCT03723603 as a single-group case series evaluating a fibrillar collagen powder dressing for chronic, stalled lower-extremity wounds. Allocation is listed as NA, masking as none, and phase as NA. The listed enrollment is 8. These details describe the registered study; they do not establish how many participants received treatment or contributed to any outcome assessment.
The intervention description says the dressing would be used in accordance with its label. After clinical site staff cleansed the wound, powder would be placed directly on it and covered with an appropriate moisture-retentive secondary dressing. The registry describes clinic visits twice a week for reapplication and weekly outpatient wound evaluations. The intervention was planned to last up to twelve weeks. Concurrent standard of care, such as compression for venous ulcers, could also be provided.
The registry lists the study start as 2018-11-09 and primary completion as 2019-06-04. Its status is terminated, and the primary outcome description says the study ended prematurely because of re-prioritization of study efforts. It also states that the data were not assessed. The record does not report a protocol explanation for termination beyond that description.
Because there is no randomized comparison or control arm, differences over time within the treated group would not, by themselves, distinguish a dressing effect from concurrent care, natural wound changes, or other factors. In this record, even a within-group outcome estimate is not reported. The design and early termination therefore limit both causal interpretation and descriptive assessment of the planned primary outcome.
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 | Fibrillar Collagen Powder Dressing |
|---|---|
| STARTED | 8 |
| COMPLETED | 5 |
| NOT COMPLETED | 3 |
Analysis population for the primary outcome, as defined in the registry: Study terminated prematurely due to re-prioritization of study efforts. Data not assessed.
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: Study terminated prematurely due to re-prioritization of study efforts. Data not assessed.
| Characteristic | Unit | Fibrillar Collagen Powder Dressing |
|---|---|---|
| Participants analysed | 0 | |
| Age, Categorical: <=18 years | — | |
| Age, Categorical: Between 18 and 65 years | — | |
| Age, Categorical: >=65 years | — | |
| Sex: Female, Male: Female | — | |
| Sex: Female, Male: Male | — | |
| Region of Enrollment: United States | participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Change in Wound Size Over Twelve Week Period, measured over Baseline to 84 days.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was change in wound size over the twelve-week period, with the listed timeframe running from baseline to 84 days. Wound size is a direct measure of the wound’s dimensions and can be used to describe whether wounds change during follow-up. The registry does not specify the measurement unit, the exact wound-size metric, how measurements were taken, or how results would be summarized. Those details are not reported in the registry record.
For a longitudinal endpoint, a change measure compares a participant’s follow-up measurement with the baseline measurement. General statistical interpretation depends on having both measurements and a defined approach to combining results across participants. A group-level estimate can describe average or typical change, but its meaning depends on the metric, handling of incomplete measurements, and analysis population.
Here, the registry states that the study was terminated prematurely and that the data were not assessed. It reports neither a numerical change estimate nor a measure of uncertainty. The endpoint was therefore specified, but the posted results do not quantify wound-size change. The record also lists changes in Bates-Jensen Wound Assessment Tool and reported pain level as secondary outcomes, without reporting their results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The principal result is the absence of an assessed primary outcome, not evidence of a particular direction or magnitude of wound-size change. Although the registry lists change in wound size from baseline to 84 days as the primary outcome, its description says the study was terminated prematurely and the data were not assessed. No estimate, confidence interval, or analysis result for wound-size change is reported in the registry record.
That distinction matters. An unreported or unassessed outcome cannot be interpreted as showing no change, benefit, harm, or equivalence. It also cannot establish that all enrolled participants completed follow-up, because completion and outcome availability are not reported. The listed enrollment of 8 is not an analyzed sample size.
The study was single-group, with no control arm. In general, observations before and after treatment in a single group can describe change over time, but they cannot isolate what caused that change. Wounds may also be affected by concurrent standard of care; the registry expressly allows such care, including compression for venous ulcers. Without a comparative design, an observed change would not by itself identify the dressing’s contribution. In this record, no such change estimate is posted in any case.
The registry identifies two secondary outcomes: change in Bates-Jensen Wound Assessment Tool and change in reported pain level. It does not report results for them. The record lists 3 outcome measures and 0 analyses, but does not explain how those counts relate to the planned measures or the absence of assessed data. No p-value, confidence interval, or other inferential result is reported for an efficacy outcome.
General statistical interpretation of a confidence interval is that it expresses uncertainty around an estimate under the assumptions of the analysis. Here, there is no reported primary estimate around which to interpret such an interval. It would therefore be inappropriate to infer precision, statistical significance, or a clinically meaningful effect from the registry entry.
The adverse-event entries should be read separately from efficacy. The record lists serious adverse-event figures and serious-event terms, but does not give an efficacy analysis or enough context to attribute those events to the dressing. The early termination and lack of assessed outcome data prevent a conclusion about wound-size change, while the single-group design would have limited causal interpretation even if descriptive changes had been posted.
9. Statistical Methods Explained
The registry describes a single-group study with allocation listed as NA and masking listed as none. There is no randomized comparison. The primary outcome was planned as change in wound size between baseline and 84 days, but the registry says the data were not assessed after premature termination. Consequently, no outcome model, estimate, or inferential test is reported for the primary endpoint.
What can a single-group design establish?
General: a single-group study can describe measurements collected from participants who receive an intervention. If repeated measurements are available, an analysis may describe change over time. Without a control group, however, that change cannot be cleanly separated from other influences, such as concurrent care or changes that would have occurred over time regardless of the intervention. This is why a within-group before-and-after comparison is not equivalent to a randomized treatment comparison.
For this study, the registry notes that concurrent standard of care could be provided. It gives compression for venous ulcers as an example. Such co-interventions are clinically relevant context for interpreting change, but the registry does not describe a method for measuring or adjusting for them. Since the wound-size data were not assessed, the record does not report even a descriptive within-group change.
What does an endpoint estimate require?
General: estimating change ordinarily requires a defined measurement, baseline and follow-up observations, and a stated summary method. If a group average is reported, it should be accompanied by information that conveys its uncertainty when inferential interpretation is intended. The registry specifies the broad endpoint and timeframe, but does not report the measurement unit, measurement procedure, summary statistic, or any estimate. It also does not report a confidence interval or p-value.
A confidence interval, in general, gives a range of values compatible with the observed data under the analysis assumptions. Its width reflects the precision of the estimate, among other things. There is no reported wound-size estimate or interval here, so precision cannot be judged. A p-value, in general, assesses how compatible data are with a specified null model; it does not measure the size or clinical importance of an effect. No p-value for the primary outcome is reported.
Why does the missing comparison matter?
General: a concurrent control group helps account for background changes and other factors shared across the study period. Random allocation can make groups comparable in expectation, subject to study conduct and chance. Neither feature is present in the registry’s single-group description. Therefore, a change in the treated group, even if it had been assessed, would not by itself demonstrate that the dressing caused the change. The registry’s allowance for standard care adds another possible influence on wound outcomes.
The record gives no analysis plan, model specification, or adjustment strategy. These are not reported in the registry record. No assumptions about a particular statistical test, covariate adjustment, repeated-measures model, or handling of outliers should be made.
How should planning illustrations be distinguished from results?
General: a sample-size calculation is a planning exercise that asks how much information a future study might need under stated assumptions. It is not an observed treatment effect and does not show that a completed study had a particular probability of detecting an effect. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a target effect expressed as a fraction of an observed effect. Those assumptions do not describe this single-group study’s allocation, and the registry does not report an assessed observed primary effect from which to interpret a planning calculation. Any sample-size illustration should therefore not be mistaken for an observed result or for the trial’s own design justification.
The registry does not report a sample-size justification, interim analyses, or a statistical analysis plan. It lists 0 analyses. That entry is consistent with the statement that data were not assessed, but the record does not explain the relationship between the two entries. No additional inferential methods can be identified from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 3 outcome measures: the primary change in wound size, change in Bates-Jensen Wound Assessment Tool, and change in reported pain level. It lists 0 analyses, and the primary outcome description says the data were not assessed. No results for the secondary outcomes are reported in the registry record.
Multiplicity arises when several outcomes or statistical tests are considered. General: examining multiple outcomes can increase the chance that at least one appears notable by chance, so an analysis plan may specify which outcome is primary and how secondary tests will be interpreted or adjusted. The registry identifies a primary outcome, but does not report a multiplicity strategy, testing hierarchy, or adjustment procedure. It is not possible to determine whether any planned approach existed outside the registry record.
Missing-data handling is also not reported. The study’s premature termination means the record does not establish how many participants had baseline or follow-up measurements, whether any observations were incomplete, or how incomplete data would have been handled. These details are not reported in the registry record. The listed enrollment is not evidence that all enrolled participants posted usable endpoint data.
The analysis population is not described. The registry does not state whether outcomes were intended to be analyzed for all enrolled participants, only those who received the dressing, or another defined group. Nor does it report exclusions or reasons for missing outcome measurements. Without an assessed outcome and a stated analysis population, readers cannot evaluate attrition, selection into analysis, or the extent to which any estimate might represent the enrolled group.
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 |
|---|---|---|---|
| Fibrillar Collagen Powder Dressing | 3 | 3 | 100.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Fibrillar Collagen Powder Dressing | 1 of 3 |
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 |
|---|---|
| Fibrillar Collagen Powder Dressing | 0 of 0 |
Most frequent serious adverse event terms
| Event term | Organ system | Fibrillar Collagen Powder Dressing |
|---|---|---|
| Death | Cardiac disorders | 1 of 3 |
| Infection | Infections and infestations | 1 of 3 |
| Fall | Injury, poisoning and procedural complications | 1 of 3 |
Serious events with the highest arm-level rate: death (33.3%), infection (33.3%), fall (33.3%).
The registry’s adverse-event entry for the fibrillar collagen powder dressing group lists 3 at risk and 3 affected for serious adverse events. It lists 0 at risk and 0 affected for other adverse events, and reports 1 death. These are registry entries, not an efficacy result. The record does not explain the relationship between the serious-event figures and the death count, or whether the death was considered related to the intervention.
The serious-event terms listed are Death, Infection, and Fall, each with a reported percentage of 33.3%. The record does not specify the denominator or provide enough detail to determine whether terms refer to event counts, participants, or mutually exclusive categories. The percentages should therefore be read as reported labels, not recalculated or interpreted as a complete risk estimate.
General: adverse-event counts describe events recorded during a study period; they do not establish causation. Attribution requires clinical and temporal context, and comparison with an appropriate control can help assess whether event rates differ. This study had no control group, and the registry does not report detailed event narratives or attribution. The figures cannot establish that the dressing caused an event, nor can they establish that it did not. The early termination and lack of assessed primary data also do not resolve the safety interpretation.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a single-group case series of fibrillar collagen powder dressing was registered for chronic, stalled lower-extremity wounds. The planned primary outcome was change in wound size from baseline to 84 days. The record also identifies changes in Bates-Jensen Wound Assessment Tool and reported pain level as secondary outcomes. It reports premature termination and says that the data were not assessed.
Accordingly, the posted results do not provide an estimate of wound-size change, uncertainty around such an estimate, or results for the secondary outcomes. They do not show that wounds improved, worsened, or remained unchanged. Absence of an assessed result is not evidence of no effect; it means the registry record does not answer the planned outcome question.
The design also limits what could be concluded even if a before-and-after change had been reported. There was no control group, and concurrent standard of care could be provided. A change over time in the treated group would not, on its own, establish that the dressing caused the change. The registry record therefore supports neither a causal conclusion nor a comparative estimate.
The adverse-event entries offer limited descriptive information, including serious-event terms and a death count, but do not establish a relationship to the intervention. Their interpretation is constrained by the lack of detailed context and a comparison group.
Overall, the record documents a planned evaluation and its early termination, rather than an assessed estimate of clinical outcome. The listed enrollment and treatment schedule provide design context, but should not be confused with analyzed outcome data or evidence of effectiveness.
13. Why This Trial Matters Statistically
This study is statistically informative in part because it illustrates the difference between a registered endpoint and an analyzed result. A primary outcome can be clearly named and assigned a timeframe, yet still provide no evidence about the outcome if the data are not assessed. Here, change in wound size from baseline to 84 days was the planned primary measure, while the registry states that the study ended prematurely and the data were not assessed.
The distinction between enrollment and analysis is also important. The registry lists an enrollment of 8, but does not report how many participants contributed to any outcome analysis. Since the record lists 0 analyses, the enrollment figure cannot be treated as the denominator for an outcome estimate.
The case series also highlights the limits of uncontrolled before-and-after evidence. General: changes observed over time can reflect treatment, concurrent care, natural variation, or other influences. A comparison group is needed to help distinguish an intervention effect from those alternatives. This study allowed concurrent standard of care and had no control arm, so causal interpretation would have been limited even if the planned outcome had been assessed.
Finally, the record makes clear why safety counts and efficacy outcomes must be interpreted separately. Serious adverse-event entries may describe events recorded during a study, but without sufficient context they do not establish attribution. Here, the registry provides adverse-event figures while reporting no assessed primary outcome. Readers should not turn either type of entry into a stronger conclusion than it supports.
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 most direct limitation is that the registry says the study was terminated prematurely and that data were not assessed. It therefore reports no primary outcome estimate, no uncertainty measure, and no secondary outcome results. The record does not state whether measurements were collected before termination or how complete they were.
The single-group design provides no control arm. Any within-group change, if available, would be difficult to distinguish from natural changes in wounds, concurrent standard of care, or other influences. The registry specifically notes that standard care could be provided, but does not describe how it was documented or incorporated into analysis.
The endpoint description is broad. The registry names change in wound size and gives the timeframe as baseline to 84 days, but does not report the unit, measurement method, or planned summary statistic. It also does not provide details on outcome-assessment procedures, analysis populations, missing-data methods, or a statistical analysis plan. These details are not reported in the registry record.
The listed enrollment of 8 does not establish the number treated, followed, or included in an analysis. Although the registry records adverse-event figures, it does not give detailed event narratives or enough context to determine attribution. The record also does not explain whether the death was considered related to the intervention.
Finally, the reason for termination is described as re-prioritization of study efforts, but the record does not give further detail. The available information cannot establish whether the listed outcomes were collected, whether analysis was considered, or whether findings exist outside the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: An Evaluation of a Collagen Dressing to Treat Chronic, Stalled Lower-extremity Wounds — NCT03723603.
- Registry record last updated 2020-03-18; status last verified 2020-02.
- Results first posted 2020-03-18.
- 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
NCT03723603 is a registered single-group case series evaluating fibrillar collagen powder dressing for chronic, stalled lower-extremity wounds. The registry lists enrollment of 8, no masking, and allocation as NA. The treatment description includes wound cleansing, application of powder, a moisture-retentive secondary dressing, clinic reapplication twice a week, weekly wound evaluation, and treatment for up to twelve weeks. Concurrent standard of care could be provided.
The primary outcome was change in wound size from baseline to 84 days. The registry states that the study was terminated prematurely because of re-prioritization of study efforts and that the data were not assessed. It reports no primary or secondary outcome analysis. The registry also lists serious adverse-event figures, the terms Death, Infection, and Fall, and 1 death, without enough context to establish attribution.
The record therefore describes the planned study and its termination, but does not provide an assessed estimate of wound-size change or a comparative treatment effect.