Investigation of the Clinical Performance of Biatain Fiber Ag on Venous Leg Ulcers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Investigation of the Clinical Performance of Biatain Fiber Ag on Venous Leg Ulcers (NCT05873257), a na na study. The primary outcome is Mean Relative Wound Area Reduction as Indication of Total Wound Healing.

2. Clinical Question

3. Trial Design

This was a completed, single-group, open-label device study of Biatain Fiber Ag in venous leg ulcers. The registry record lists the allocation as NA and describes the intervention as non-comparative, with one arm and no control group. The study was sponsored by Coloplast A/S. Its listed phase is NA. Enrollment was 50. The study start date was 2023-07-31, primary completion was 2024-05-17, and status is COMPLETED.

The intended exposure period was four weeks (+/- 2 days). Participants were asked to attend six study visits, with dressing changes once per week at the research facility. Wounds were to be cleaned and assessed, and photographs uploaded to digital software. The intervention is identified as a device, rather than a drug. These design details describe the planned conduct; the registry record does not report visit attendance, adherence, the number completing the planned period, or the duration actually received by each participant.

Because the study has a single arm, wound-area observations can describe participants' measured status during the study but cannot separate changes occurring during the study from changes that might have occurred without the dressing. Open-label conduct also means that participants and study personnel were not masked to the intervention. The record does not describe blinded outcome assessment. Wound area was measured from photographs, with a ruler near the wound used to calibrate image dimensions and a manually traced wound border used to obtain area.

The registry record does not report a detailed statistical analysis plan, a sample-size justification, or criteria for determining clinical importance. The planning illustration described for sample-size calculations is not the trial's own design justification and should not be interpreted as observed power. The posted record lists one primary outcome measure but no analyses. These omissions limit how fully the design and its statistical intentions can be evaluated.

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: The primary analysis was based on subjects exposed to investigational device and with reliable baseline assessment of wound area. One subject was omitted (entire wound not captured on photo at baseline). The last observation 'on-treatment' was used in the analysis. The sensitivity analysis was conservatively based on the entire ITT population also including a subject with an unreliable wound area assessment at baseline. The analysis was performed as the primary analysis.

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 Mean Relative Wound Area Reduction as Indication of Total Wound Healing, measured over 4 weeks.

The primary endpoint is mean relative wound area reduction, reported in relative wound area reduction (%), at four weeks. It is described as an indication of total wound healing. Wound area was to be measured from photographs: a ruler of known dimensions placed near the wound edge was used to calibrate the image, the wound border was traced manually, and planimetric software calculated the area.

Area-based outcomes provide a continuous measure of wound size rather than a simple classification of whether a wound has healed. A relative measure expresses change in relation to the wound's baseline size, which can help make changes interpretable across wounds that begin at different areas. This is a general statistical explanation; the registry record does not report the exact calculation formula used for the relative reduction measure.

The endpoint is a mean, so its value would describe the average result in the analyzed participants, not the experience of every individual. The stated dispersion measure is a 95% confidence interval, which would convey uncertainty around that mean. However, neither the mean estimate nor its confidence interval is reported in the registry record. Without those values, the direction, size and precision of the measured average change cannot be assessed from the posted results. The endpoint definition alone is not evidence of a particular treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean endpoint represent?

The primary outcome is a continuous measure, and the registry record specifies the mean as its summary. A continuous measure can take a range of values rather than placing each participant into only one category. The mean gives a single summary of the analyzed observations, but it does not show how widely individual results vary or whether a small number of observations strongly influence the average. Those questions require additional summaries or participant-level information, which are not reported in the registry record.

For this study, the measure is relative wound area reduction (%), assessed at four weeks. The registry record explains that wound photographs were calibrated using a ruler, after which the wound border was traced manually and software calculated the area. Calibration is intended to translate image dimensions into a measure of physical area. Manual tracing makes the identified border part of the measurement process; the record does not report whether tracing was checked by a second assessor, whether assessors were blinded, or how disagreements were resolved.

How should a confidence interval be read?

The stated dispersion measure is a 95% confidence interval around the mean. In general, a confidence interval presents a range of values compatible with the observed data under the method's assumptions and communicates uncertainty in the estimated mean. A narrower interval indicates greater precision than a wider interval, though precision alone does not determine clinical importance. The interval does not show the spread of individual participants' measurements; it concerns uncertainty about the mean.

The registry record does not report the mean or its interval. Accordingly, there is no basis to describe the interval's width, whether it includes a particular reference value, or how precisely the mean was estimated. A confidence interval is not a substitute for the underlying estimate, and naming the interval in an outcome definition does not mean that its numerical limits are available.

What does a single-group design estimate?

A single-group study can describe outcomes recorded in participants who receive the study intervention. If baseline and follow-up values are available, an analysis may characterize change within that group. Such a description does not, on its own, estimate a contrast against a group receiving another intervention or no intervention. Without a concurrent comparison, differences over time cannot be attributed uniquely to the study device. This is a general design principle and does not imply that a particular unmeasured influence occurred in this study.

The record calls the study non-comparative and open-label. Allocation is listed as NA, and there is no control arm. The registry record does not specify a statistical test, an adjustment model, or a method for handling repeated observations beyond stating that the last observation on-treatment was used in the primary analysis. It would be inappropriate to infer an unreported model from the fact that the endpoint is a mean.

Why can over-dispersion matter?

For continuous outcomes, the mean alone may not capture the variability of participant results. General statistical methods often rely on assumptions about how observations vary, and a model that understates variability can give uncertainty intervals that are too narrow. Over-dispersion refers broadly to variability greater than a chosen model expects. Its relevance depends on the data and analysis method. The registry record does not report an over-dispersion assessment, and there is no basis to say whether it was relevant to this endpoint.

The stated confidence interval would be interpreted in light of the method used to calculate it. That method is not reported in the registry record. The outcome description identifies a mean and interval but does not specify the distributional assumptions, standard-error calculation, or any robust alternative. These details matter for evaluating how well an interval reflects uncertainty, particularly when data are variable or the analysis population is limited.

What do planning calculations mean?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. For time-to-event outcomes, the illustration would count total events; for other outcomes, it would report participants per arm. These are assumptions for an illustrative planning exercise, not evidence that this single-group study was designed with those parameters.

A sample-size calculation addresses how many observations a future design might need under specified assumptions. It is not a result from the enrolled participants and is not observed power. In particular, the equal-allocation, two-arm assumption does not match the registry record's one-arm design. The illustration should therefore be read as planning information, not as a direct description of this trial's design or as a substitute for its observed endpoint results. The registry record does not report a trial-specific sample-size justification.

The sponsor's primary analysis, if posted, would be the relevant analysis for interpreting the registered outcome. No primary analysis result is listed in the registry record. There are no recalculated estimates described in the posted information, so no recalculation can be compared with a sponsor analysis. More generally, a recalculation from summary statistics would answer a narrower question than the original analysis if it were unadjusted or used different assumptions. Such calculations should not be treated as a replacement for the trial's prespecified or sponsor-reported analysis.

What can the posted analysis information support?

The registry record lists one outcome measure and zero analyses. It describes the intended primary analysis population and mentions a sensitivity analysis, but the sensitivity-analysis description ends before its method is fully stated. It is therefore not possible to assess the alternative assumptions, compare its result with the primary analysis, or determine how robust the findings were to analytic choices. The numerical primary outcome is also absent. Together, these gaps mean that statistical precision and the stability of any estimated effect cannot be evaluated from the posted record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure, the mean relative wound area reduction at four weeks, and zero analyses. A single registered primary endpoint can help focus interpretation, but the record does not report a complete analysis plan, testing hierarchy, or multiplicity adjustment. It is therefore not possible to determine whether other outcomes or analyses were considered in a broader statistical plan. The presence of one listed endpoint should not be read as proof that no additional analyses were performed.

Missing data are relevant to the primary measure because the analysis population required exposure to the device and a reliable baseline wound-area assessment. One subject was omitted because the entire wound was not captured in the baseline photograph. The record says the last observation on-treatment was used in the analysis. It does not state the number analyzed, identify all missing follow-up observations, or explain how missing measurements other than the stated baseline-photo omission were handled.

The primary-outcome description begins to mention a sensitivity analysis, but the registry record does not report its complete method or result. No imputation method, missing-data assumption, or comparison between primary and sensitivity analyses is reported in the registry record. Consequently, the effect of missing observations on the estimate cannot be evaluated. The omission of one subject for an unusable baseline image is a specific documented exclusion; it does not establish that all other data were complete.

The record does not define multiple analysis populations beyond the description of the primary analysis population. It is not possible to determine whether separate intention-to-treat, per-protocol, or safety populations were prespecified. These terms should not be inferred from the limited population description. The posted information supports only the stated inclusion condition, the noted omission, and the use of the last on-treatment observation.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

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: hospitalised with pulmonary oedema (2.0%).

The adverse-event record lists 50 participants at risk in the main arm. It reports one participant affected by a serious adverse event, eight affected by other adverse events, and zero deaths. The listed serious-event term is hospitalised with pulmonary oedema, with 2.0% shown. These counts describe the safety information recorded for this single group; they are not a comparison of event rates between treatments.

Serious adverse events and other adverse events are separate categories in the record. The figures should be read as counts of affected participants, not as a complete description of event severity, duration, recurrence, or outcome. The record does not provide additional detail on the eight other adverse events, nor does it describe how many total events occurred for each affected participant. It does not provide a causal assessment establishing whether events were related to the device.

With no control arm, these observations cannot show whether event frequency was higher or lower than it would have been under another treatment or no intervention. The study's four-week planned exposure period also does not establish what the safety profile would be over a different duration. Zero deaths is the recorded count in this study group; it should not be interpreted as evidence that the risk of death is absent. The adverse-event figures are descriptive and should be considered alongside the record's limited follow-up and reporting information.

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

The registry record establishes that a completed, open-label, single-group study enrolled 50 participants with venous leg ulcers and evaluated Biatain Fiber Ag. It defines a primary endpoint of mean relative wound area reduction (%) at four weeks and describes a photographic planimetry approach. These are useful details for understanding the intended measurement and study context.

However, the posted record does not report the numerical mean relative wound-area reduction or its 95% confidence interval. As a result, it does not show the observed average result or its precision. The absence of a numerical estimate is not the same as a result of zero, and it does not show that the intervention had no effect. It means that the primary outcome cannot be quantitatively interpreted from the posted information.

Even if a within-group change were reported, the one-arm design would not establish how outcomes would have differed under a comparator. Open-label conduct and manual photographic tracing are also important context for interpreting measurements, particularly because the record does not describe blinded assessment. The endpoint measures wound area; it is not, by itself, a complete account of all aspects of wound healing or participant experience.

The safety record gives descriptive counts for serious and other adverse events and deaths among participants in the single arm. It does not establish a comparative safety profile or causality. The planning illustrations are not observed trial outcomes or observed power. Overall, the record supports a description of the study design, endpoint, measurement process, and limited safety counts, but does not support a quantified claim about the primary outcome or a comparative treatment effect.

13. Why This Trial Matters Statistically

This study illustrates how an endpoint can be described in detail while its result remains unavailable in the registry record. The outcome name, time point, unit, and photographic measurement procedure clarify what investigators intended to quantify. Yet statistical interpretation depends on the actual estimate and its uncertainty, neither of which is reported for the primary outcome. Endpoint definitions and outcome findings are distinct kinds of information.

The single-group design is also statistically important. A mean change within an exposed group can be informative as a description, but it cannot by itself distinguish an intervention-associated change from other changes over time. The absence of a comparator shapes the question that the study can answer, regardless of how carefully wound area is measured. Open-label conduct and manual tracing further emphasize the importance of understanding how measurements were obtained and whether assessment was independent or blinded; those details are not reported.

The record also shows why analysis-population and missing-data descriptions matter. A baseline image that did not capture the entire wound led to one subject being omitted from the primary analysis, while the stated use of the last on-treatment observation indicates an analytic choice about available measurements. Without the analyzed group size, complete missing-data methods, and sensitivity-analysis results, readers cannot assess the potential influence of exclusions and incomplete observations.

Finally, the sample-size planning illustration must be separated from the study's observed evidence. Its assumptions concern a two-arm, equal-allocation planning scenario, whereas this trial is non-comparative and single-group. A planning calculation can inform future research design under explicit assumptions; it cannot fill in a missing endpoint result or establish that a study had a particular level of observed power. Careful separation of design, estimates, uncertainty and safety counts prevents readers from drawing stronger conclusions than the registry record 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 primary limitation for interpreting this trial from the registry record is that its numerical primary outcome is not reported. Although mean relative wound area reduction and a 95% confidence interval are specified, neither value is available. No estimate of the magnitude or precision of the primary result can therefore be assessed.

The one-arm, non-comparative design provides no concurrent control for interpreting change over time. The study is open-label, and the outcome uses a manually traced border on wound photographs. The registry record does not report whether image assessors were blinded, how measurement consistency was evaluated, or whether repeat assessments were performed. These are relevant measurement details, not evidence that a particular bias occurred.

The primary analysis population required exposure to the device and a reliable baseline wound-area assessment. One subject was omitted because the full wound was not captured in the baseline photograph. The number analyzed is not reported in the registry record, and the handling of other missing measurements is not described. The record mentions a sensitivity analysis, but its description and result are incomplete. This prevents assessment of the effect of missing data or the robustness of the analysis.

The registry record lists zero analyses and does not provide a detailed statistical plan, sample-size justification, analysis method for the mean, or a multiplicity approach. It also does not report a blinded assessment procedure or a comparative estimate. The adverse-event information is limited to counts and a listed serious-event term, without a comparative safety group or a causal assessment. These limitations restrict interpretation of both the primary endpoint and safety observations; they do not, by themselves, indicate the direction of an unreported result.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Investigation of the Clinical Performance of Biatain Fiber Ag on Venous Leg Ulcers — NCT05873257.
• Registry record last updated 2025-06-03; status last verified 2025-05.
• Results first posted 2025-06-03.
• 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.

18. Record Summary

The registry record describes a completed, open-label, single-group device study of Biatain Fiber Ag in venous leg ulcers. Enrollment was 50, and participants were intended to use the dressing for four weeks (+/- 2 days), with dressing changes once per week at the research facility. The primary endpoint was mean relative wound area reduction (%) at four weeks, measured from calibrated wound photographs with manually traced borders.

The primary analysis was described as involving exposed subjects with reliable baseline wound-area assessments. One subject was omitted because the entire wound was not captured in the baseline photograph, and the last observation on-treatment was used. The numerical primary result and its 95% confidence interval are not reported in the registry record. The record lists one outcome measure and zero analyses.

Safety information lists one participant with a serious adverse event, eight with other adverse events, and zero deaths among 50 at risk; hospitalised with pulmonary oedema is listed at 2.0%. With no comparator arm, these are descriptive single-group observations.