Evaluation of Exufiber Ag+ and Other Gelling Fibre Dressings: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Exufiber Ag+ and Other Gelling Fibre Dressings (NCT03249909), a non-randomized na study. The primary outcome is Change in Exudate Status From Baseline to Last Visit.

2. Clinical Question

3. Trial Design

This was a completed clinical investigation of gelling fibre dressings for wounds and injuries. The registry lists an enrollment of 109, a start date of 2017-08-11, and a primary completion date of 2019-08-19. It identifies Molnlycke Health Care AB as the sponsor. The phase is listed as NA.

The registry describes the allocation as non-randomized, masking as none, and model as single group. It also lists three dressing groups: Exufiber Ag+, Exufiber, and Aquacel Ag Extra. The arm descriptions state that chronic wounds, acute wounds, and pressure ulcers were treated, with each group’s data analyzed separately and no comparative analysis. These descriptions matter when interpreting the results: the study does not establish a randomized contrast between the products, and differences between separately analyzed groups cannot be attributed to the dressings on the basis of this design alone.

The primary outcome concerned change in exudate status over 4 weeks or earlier if the wound was dry or healed. The registry also lists secondary outcomes concerning 4-week wound status, wound area reduction, dressing-change frequency, wound-bed tissue type, malodour, redness or irritation, maceration, and dressing handling and technical performance. The record lists 10 outcome measures. It does not give additional detail about the study setting, recruitment procedures, participant characteristics, or a planned comparison between products.

The outcome population is described as Intent To Treat with evaluable data for the change analysis. The record gives evaluable counts separately for each dressing group. That label should be read alongside the stated evaluability requirement: these counts do not represent every person enrolled, and the record describes unavailable outcome measurements and use of last observation carried forward. The statistical plan beyond the stated primary test and significance level is not reported in the registry record.

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: All enrolled subjects were assigned to a treatment group and treated in compliance with the Instructions For Use. No subject was excluded from the intent-to-treat (ITT) and safety population during analysis.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent To Treat (ITT) population with evaluable data to analyze change from baseline to last visit (n=75 for Exufiber Ag+; n=14 for Exufiber; n=16 for Aquacel Ag Extra)

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 Change in Exudate Status From Baseline to Last Visit, measured over 4 weeks (28 days) or earlier if the wound is dry or healed.

The primary endpoint measured change in wound exudate status from baseline to the last visit. Exudate status was based on dressing condition and classified as Dry, Moist, Wet, Saturated, or Leaking. The analysis then summarized change using three categories: Decrease, Equal/Unchanged, or Increase. The planned observation period was 4 weeks (28 days), with an earlier last visit if the wound was dry or healed.

In general, a categorical endpoint can describe change without treating the underlying categories as if the gaps between them were measured on a continuous scale. A direction-of-change outcome is useful for asking whether participants tended to move toward less exudate, remain unchanged, or move toward more exudate. It is a description of change in the measured status, not by itself an explanation of why the change occurred.

Exudate handling is the focus stated in the investigation’s official title and brief summary. The endpoint therefore addresses a feature of wound management that the study set out to observe. It does not, on its own, measure every aspect of wound healing or establish comparative benefit between dressings. The registry record does not report the number of participants in each change category, the test statistic, a p-value, or a confidence interval. The observed distribution and its precision cannot be evaluated from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the Sign test address?

The registry says that the primary endpoint was analyzed with a two-sided Sign test. In general, the Sign test is a nonparametric method for paired observations that focuses on the direction of change rather than the size of each change. For this endpoint, the registry grouped change as a decrease, equal or unchanged, or an increase. The method is suited to a question about whether changes tend more often in one direction than the other, without requiring a normal distribution for a numerical outcome.

The test does not make the categories equivalent to a continuous measurement. Nor does it describe how far a participant moved between the categories of Dry, Moist, Wet, Saturated, and Leaking. The test’s interpretation depends on which observations contribute to its comparison, including how unchanged results are handled. The record names the test and the three change categories, but does not report further implementation detail or the observed category counts.

What does two-sided mean?

In general, a two-sided test allows evidence in either direction to count against the null hypothesis. Here, that is consistent with testing for a pattern of change without restricting the question to a decrease in exudate status. A two-sided test does not mean that an effect was found, and it does not identify the direction of any observed change. The registry lists a significance level of 0.05, but does not report a p-value or state whether the test crossed that threshold.

What is the role of the significance level?

In general, a significance level is a prespecified threshold used when interpreting a statistical test under its assumptions. It is not the probability that a treatment works, the probability that a result is due to chance, or a measure of effect size. The stated level of 0.05 describes the analysis approach, while the missing test result prevents assessment of the analysis outcome. The statistical plan beyond this information is not reported in the registry record.

How should the change categories be understood?

The starting status was based on dressing condition, classified as Dry, Moist, Wet, Saturated, or Leaking. The endpoint then reduced the transition to a direction: Decrease, Equal/Unchanged, or Increase. In general, this kind of reduction can make a direction-of-change question easier to summarize, but it discards information about the particular starting and ending categories. It also does not show whether participants with different wound types had different patterns. The registry describes chronic wounds, acute wounds, and pressure ulcers, but reports no subgroup results for the primary endpoint.

The primary outcome is described in participants, with evaluable counts for each group. The record does not report the number of participants in each change category, so the distribution cannot be inspected. It also does not report an effect estimate or interval that would convey uncertainty around the observed pattern.

What does last observation carried forward assume?

The analysis description says that if a participant had a missing value at 4 weeks (Visit 5), last observation carried forward was applied from Visit 2 (1 week). In general, this method substitutes the participant’s earlier recorded value for a missing later value. It allows an analysis dataset to include a value for a time point that was not observed, but the substituted value is not a measurement made at that later time. The method can be inaccurate if status changes after the last observed visit, and it does not account for uncertainty about that unobserved change.

The record notes that three participants treated with Exufiber Ag+ did not have evaluable data. It describes two who did not complete Visit 2 or later visits, both with chronic wounds, and one with a chronic wound who completed the investigation only until Visit 2 but had no exudate status data reported at that visit. It also notes one Exufiber participant who completed Visit 2 or a later visit. These details illustrate that missingness and evaluability are relevant to the endpoint. The record does not provide further missing-data sensitivity analyses.

Why is the design important to interpretation?

In general, random allocation helps make treatment groups comparable in expectation, while masking can limit some forms of measurement or assessment bias. This study is listed as non-randomized and unmasked, with separately analyzed groups and no comparative analysis. Thus, the primary analysis is best interpreted as a within-group description of change, rather than a randomized estimate of the difference between products. The registry record does not report methods for adjusting group comparisons, and it does not report a planned comparative analysis.

The registry also lists sample-size planning assumptions: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. Such sample-size calculations are planning illustrations, not observed power and not evidence that the study had a particular chance of detecting an effect. The actual sample-size justification for this investigation is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists the primary exudate-status outcome and secondary outcomes covering 4-week wound status, wound area reduction, dressing-change frequency, wound-bed tissue type, malodour, redness or irritation, maceration, and dressing handling and technical performance. It also lists 10 outcome measures. When multiple outcomes are examined, the chance of at least one apparently notable finding can increase. In general, multiplicity procedures can address that issue, but the registry record does not report whether an adjustment was planned or used. It is also not clear from the record how the listed outcome measures relate to the single analysis listed.

The record describes the primary analysis as using the Intent To Treat population with evaluable data to analyze change from baseline to last visit. It reports group-specific evaluable counts: n=75 for Exufiber Ag+, n=14 for Exufiber, and n=16 for Aquacel Ag Extra. The word Intent To Treat should therefore be read together with the explicit evaluability condition; the record does not say that every enrolled participant contributed an observed primary outcome.

For missing 4-week values, the analysis description says last observation carried forward was applied from Visit 2 (1 week). In general, this approach assumes that the earlier status can stand in for the unavailable later status. It may not reflect what happened after the last recorded visit. The registry record does not report sensitivity analyses using alternative assumptions for missing outcomes, nor does it describe a missing-data model or explain how missingness was evaluated.

The record gives reasons that three Exufiber Ag+ participants were not evaluable and notes one Exufiber participant who completed Visit 2 or a later visit. Further detail about missing outcome data, including an account for every group, is not reported in the registry record. The primary outcome counts, statistical test result, and any interval estimate are also not reported, limiting interpretation of both the result and its uncertainty.

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: infection on non-study foot (6.2%), syncope (1.3%), arteriovenous fistula (1.3%), revisional transmetatarsal amputation right foot (1.3%), pneumonia (1.3%).

The safety listing gives serious adverse event and other adverse event counts by dressing group, alongside the number at risk for each category. For Exufiber Ag+, the record lists 7 serious adverse events among 78 at risk and 14 other adverse events among 78 at risk. For Exufiber, it lists 0 serious adverse events among 15 at risk and 5 other adverse events among 15 at risk. For Aquacel Ag Extra, it lists 1 serious adverse event among 16 at risk and 2 other adverse events among 16 at risk. The registry lists 0 deaths in each group.

The serious-event terms listed include Infection on non-study foot (6.2%), Syncope (1.3%), Arteriovenous fistula (1.3%), Revisional transmetatarsal amputation right foot (1.3%), Pneumonia (1.3%), and Kidney injury (1.3%). These terms and percentages are registry listings; they should not be treated as proof that a dressing caused an event. The record does not explain attribution or provide a comparative safety analysis. The groups were non-randomized and analyzed separately, so their counts should not be interpreted as a like-for-like comparison.

In general, an event count describes recorded events or affected participants according to the registry’s reporting convention; it does not by itself establish causation or quantify comparative risk. The record does not provide enough detail to resolve how the listed event terms relate to individual participants or to assess differences between groups.

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

The investigation’s stated focus was the effect of gelling fibre dressings on wound exudate and bioburden in medium to high exuding wounds. The primary endpoint specifically assessed change in exudate status, using dressing condition to define categories and classifying the direction of change over the follow-up period. The registry records a planned Sign test and gives evaluable counts for each dressing group.

However, the registry record does not report the primary outcome counts, test result, effect estimate, or confidence interval. It therefore does not show the observed pattern of exudate change or how precisely that pattern was estimated. The planned test and significance threshold describe methods, not a result. The record also does not report the results for the listed secondary outcomes, so those outcomes cannot fill the gap in interpretation of the primary endpoint.

The study was non-randomized, unmasked, and the dressing groups were analyzed separately without comparative analysis. Consequently, the record does not provide a controlled basis for attributing observed changes to a specific dressing or ranking the products. A within-group change, if available, would describe what was observed among participants in that group, but would not by itself distinguish a dressing effect from other influences over time.

The missing-data approach is also relevant. Last observation carried forward used a Visit 2 value for a missing 4-week value, according to the analysis description. In general, a carried-forward value is not an observed status at the later time point. The registry does not report sensitivity analyses to show how conclusions might vary under other assumptions about missing outcomes.

Thus, the record establishes what the primary question was and how the study said it would analyze change, but it does not provide enough primary outcome results to determine the direction, magnitude, or precision of that change. It cannot support a claim that one product is better or worse than another, or a causal claim about dressing effects. The safety listings likewise describe events without establishing their cause.

13. Why This Trial Matters Statistically

This investigation is statistically informative because it makes the distinction between observing change within a treatment group and estimating a comparative treatment effect especially important. The registry lists three dressing groups, but describes non-randomized allocation and separate analyses without comparative analysis. Readers should not interpret parallel group descriptions as if they came from a randomized head-to-head trial.

The primary endpoint also illustrates the choices involved in analyzing categorical clinical data. Exudate status was classified using dressing condition, while the analysis focused on whether status decreased, remained unchanged, or increased. In general, a direction-based outcome can offer a clear summary of change while omitting detail about the starting and ending categories. Understanding what a statistical test uses—and what its summary leaves out—is essential for interpreting an endpoint.

The missing-data description is another key statistical feature. Last observation carried forward substitutes an earlier observation for an unavailable later one. That may create a complete analysis value, but it does not make the later status known. The stated evaluability requirement and the group-specific counts should therefore be considered alongside the method used for missing 4-week measurements.

Finally, the registry record describes the planned analysis but does not report the primary endpoint counts or test result. This separates methodological transparency from result interpretability: knowing which test was planned does not reveal what the study found or how uncertain an estimate was. The record supports careful discussion of design and analysis choices, while leaving the primary statistical finding unavailable.

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 principal limitation for interpreting the primary endpoint is that the registry record does not report the change-category counts, the Sign test result, an effect estimate, or a confidence interval. Without those results, the direction and precision of the observed change cannot be assessed. The registry’s description of the analysis is not a substitute for its outcome data.

The design is non-randomized, unmasked, and the three dressing groups were analyzed separately without comparative analysis. There is therefore no randomized between-group contrast in the reported analysis. The registry model is listed as single group, while the record also names three dressing groups; it does not describe a comparative framework connecting those groups.

The primary analysis is described as Intent To Treat with evaluable data, and the listed evaluable counts are not the same as the enrollment figure. The record describes three Exufiber Ag+ participants as not evaluable and gives reasons related to visit completion and missing exudate status. It also notes one Exufiber participant who completed Visit 2 or a later visit. More detail about missing outcome data across groups is not reported in the registry record.

Last observation carried forward was used for missing 4-week values, drawing from Visit 2 (1 week). The record does not report sensitivity analyses or other missing-data methods. It also does not report the multiplicity approach for the several listed outcomes, details of a sample-size justification, or further statistical-plan information. These omissions limit assessment of robustness, precision, and the scope of the analyses.

The safety listing gives event counts and selected terms but does not report a comparative safety analysis or event attribution. Participant characteristics and further study-setting details are not reported in the registry record. These limitations constrain both causal interpretation and the ability to assess how broadly the findings might apply.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluation of Exufiber Ag+ and Other Gelling Fibre Dressings — NCT03249909.
• Registry record last updated 2020-09-29; status last verified 2019-03.
• Results first posted 2020-09-29.
• 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.

18. Record Summary

NCT03249909 is a completed, non-randomized clinical investigation sponsored by Molnlycke Health Care AB. It studied Exufiber Ag+, Exufiber, and Aquacel Ag Extra in chronic wounds, acute wounds, and pressure ulcers. The registry lists enrollment of 109 and dates of 2017-08-11 for study start and 2019-08-19 for primary completion.

The primary endpoint was change in exudate status from baseline to the last visit, scheduled at 4 weeks or earlier if the wound was dry or healed. The analysis description specifies a two-sided Sign test at significance level 0.05 and last observation carried forward for missing 4-week values. The groups were analyzed separately, without comparative analysis.

The registry record does not report the primary outcome counts or test result. It therefore does not establish the observed direction, size, or precision of the primary change, and it does not support a randomized comparison among the dressings.