OASIS Wound Matrix (Oasis) Mechanism of Action: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for OASIS Wound Matrix (Oasis) Mechanism of Action (NCT00570141), a randomized phase 4 study. The primary outcome is Decrease in Wound Area From Baseline After 12 Weeks of Treatment or Until Wound Closure, Whichever Occurred First..

2. Clinical Question

3. Trial Design

The record identifies this as a Phase 4 study of OASIS Wound Matrix, sponsored by Healthpoint. The study title describes a mechanism-of-action case study, and the official title describes documentation of subjects with diabetic foot ulcers or venous stasis ulcers being treated with OASIS. The listed enrollment was 13, and the study status is completed. The recorded start was 2007-10 and the primary completion was 2009-04.

The design information needs cautious reading. Allocation is listed as randomized, masking as none, and the model as single group. The arm description says there was a single arm and that Oasis was used on all subjects. These entries do not establish a randomized comparison: the record does not describe a second arm, allocation procedures, or a comparator. The reason for the randomized-allocation listing alongside a single-group model is not reported in the registry record.

The intervention is classified as a device. The brief summary says that OASIS Wound Matrix would be applied to wounds and that healing wounds would undergo sequential biopsy to explore mechanism of action. The record does not provide a detailed biopsy schedule or report biopsy results. For the primary outcome, wound measurements were made weekly, spaced 7 +/- 1 day apart, up to 12 weeks or wound healing, whichever occurred first. The primary analysis population is described as per protocol, but the criteria for that population are not reported in the registry record.

The record lists two outcome measures but provides details for only the primary endpoint in the available study details. It reports zero analyses. The absence of a second-arm outcome and of reported analysis results means that the design description is more informative about the intended measurement than about comparative efficacy.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis was Per Protocol

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 Decrease in Wound Area From Baseline After 12 Weeks of Treatment or Until Wound Closure, Whichever Occurred First., measured over Baseline and weekly up to 12 weeks.

The primary endpoint is the decrease in wound area, measured in cm2, from baseline to the final measurement. The final measurement was taken at 12 weeks or when the wound healed, whichever occurred first. The endpoint was expressed as a mean, with standard deviation specified as the measure of dispersion. The analysis population was per protocol.

Wound area is a continuous measurement: it can take different numerical values across wounds, rather than being limited to a yes-or-no outcome. Tracking area over time can describe change in the wound’s measured size during treatment. The endpoint’s direction is defined in the record as baseline measurement minus final measurement, so a positive decrease corresponds to a smaller final area than baseline. This is an explanation of the endpoint’s arithmetic definition, not a claim about the study’s observed result.

Using the last measurement before closure or the end of follow-up allows the endpoint to reflect different observation periods for wounds that close earlier and those that remain open through the scheduled period. That choice also means the endpoint combines a fixed calendar limit with an event-based stopping point. The record does not report how many subjects reached wound closure before 12 weeks, nor the observed mean decrease or its standard deviation. Consequently, the endpoint’s size and precision cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measure, summarized as a mean decrease in wound area. A mean describes the average value across the observations included in an analysis. The standard deviation describes how spread out individual values are around that mean. A mean alone would not show whether wound-area changes were similar across subjects or varied substantially; the standard deviation would help describe that variation. The registry record specifies both summaries but does not report their values.

What does the endpoint calculation represent?

The record defines decrease as baseline wound area minus the final measured area. The final measurement was taken after 12 weeks of treatment or at wound closure, whichever occurred first. This is a within-subject change calculation: each included subject’s baseline measurement is compared with that subject’s final measurement, and the resulting decreases are summarized. It is not a comparison between treatment arms because the record describes only one arm.

Weekly measurements were scheduled, spaced 7 +/- 1 day apart, up to the stated endpoint. Repeated measurements can describe the course of wound area during follow-up, but the primary endpoint uses the baseline and final measurements as defined in the record. The record does not report a model using all weekly measurements, a slope over time, or another repeated-measures analysis. Such methods should not be inferred merely from the existence of weekly measurements.

What would uncertainty measures add?

General statistical explanation: an estimate such as a mean is subject to sampling uncertainty because a different set of subjects could yield a different estimate. A confidence interval is a range calculated by a statistical procedure to express uncertainty around an estimate under its assumptions. A narrower interval generally indicates greater precision, while a wider interval indicates less precision. No confidence interval is reported for this endpoint, so its precision cannot be assessed from the registry record.

A p-value is a statistic used in a specified hypothesis test to describe how compatible data are with a null hypothesis under the test’s assumptions. It does not measure the size or clinical importance of an effect. The record reports zero analyses and no p-value, test statistic, or hypothesis test for the primary outcome. There is therefore no reported test result to interpret.

Why does the analysis population matter?

The primary population is identified as per protocol. In general, a per-protocol analysis includes participants who meet specified adherence or eligibility criteria for the analysis. The precise rules vary by study and must be stated to understand who contributed data. Those rules, the number included, and the handling of subjects who did not complete follow-up are not reported in the registry record. It is not possible to determine from the record whether the analysis included all 13 enrolled subjects.

In general, excluding subjects from an analysis can affect how representative the analyzed group is of those enrolled. If the reasons for exclusion are related to outcomes, the resulting estimate may be biased. This is a general concern, not evidence that exclusions occurred in this study. The record does not report exclusions or the reasons for them.

How should a one-group design be understood?

General statistical explanation: a single-group study can describe measurements among participants who receive an intervention, including change from baseline. Without a comparison group, it cannot estimate a between-group difference or distinguish changes associated with the intervention from other changes occurring over time. This distinction matters even when measurements are repeated, because observing a trajectory does not supply the missing counterfactual comparison.

The record lists randomized allocation while also describing a single-group model and one arm. Randomization normally refers to assignment among alternatives, but the record does not identify alternatives or explain the listing. No randomized contrast or analysis is reported. The safest interpretation is limited to the described single arm, without assuming that a comparative randomized design was implemented.

What can planning calculations establish?

General statistical explanation: sample-size planning calculations describe how many participants might be needed under specified assumptions about an effect, variability, significance level, allocation, and statistical method. They are planning illustrations, not observed outcomes and not evidence that a study had a particular probability of detecting an effect after completion. The record describes an illustration based on a fraction of the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. However, the trial is described as single group, and no observed primary effect or calculated planning sample sizes are reported in the registry record. Those assumptions do not establish the trial’s own design rationale or a valid comparison for this study.

Overall, the statistical information defines a continuous endpoint and its planned summary, but does not include the numerical outcome, uncertainty, inferential test, or analysis details needed for a full statistical interpretation.

10. Multiplicity, Missing Data and Analysis Populations

The record lists two outcome measures, but only the primary outcome is described in the study details. The other outcome’s name, definition, timing, and analysis are not reported in the registry record. It reports zero analyses, so there are no reported estimates or tests for either outcome to compare.

Multiplicity arises when more than one outcome, time point, subgroup, or statistical test is examined. In general, conducting many tests can increase the chance of at least one apparently notable finding under a null hypothesis. Statistical plans may address this through prespecified primary outcomes or adjustment procedures. The record does not report a multiplicity strategy, such as adjustment for multiple testing, or details of any secondary analyses. No such strategy should be assumed.

Missing-data methods are also not reported in the registry record. The primary endpoint uses baseline and a final measurement taken at 12 weeks or wound closure, whichever occurred first. The record does not state what happened if a subject lacked a baseline or final wound measurement, withdrew, or otherwise did not contribute a complete endpoint. It also does not report the number of participants included in the per-protocol analysis or how missing measurements were handled.

The per-protocol designation identifies the stated analysis population but does not, by itself, explain eligibility rules, exclusions, or missing-data handling. These omissions limit assessment of selection and missingness. They also prevent determining whether the outcome summary, if one were available, would represent all enrolled subjects or only a subset. The record does not report interim analyses or a detailed statistical analysis plan.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event figures list 13 subjects at risk for serious adverse events and 0 affected by a serious adverse event in the OASIS Wound Matrix group. The record lists no serious adverse-event terms. This reports the count recorded for the group; it does not establish that the device caused or prevented any event, and it does not describe event ascertainment or follow-up in detail.

For other adverse events, 13 subjects were at risk and 6 were affected. The record does not provide the event terms, counts of individual events, severity, timing, or attribution. The number of subjects affected is not necessarily the same as the number of events, since a subject can experience more than one event. The record does not clarify that distinction for the other adverse-event figure.

Deaths are listed as null, which means the death figure is not reported in the registry record; it should not be read as a reported count of zero. These safety summaries are descriptive. With no comparator and no additional event detail, they do not establish comparative safety or causation.

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

The record establishes that a completed Phase 4 study enrolled 13 subjects with diabetic foot ulcers or venous stasis ulcers and used OASIS Wound Matrix in a single arm. It defines a primary endpoint based on decrease in wound area from baseline to a final measurement at 12 weeks or wound closure, whichever occurred first. It also reports that measurements were scheduled weekly, spaced 7 +/- 1 day apart.

Those design details do not constitute an outcome finding. The observed mean decrease and standard deviation are not reported in the registry record, and no statistical analyses are reported. The record therefore does not show the amount of wound-area change, its variability, or the precision of an estimate. It cannot establish from the posted information whether the average change was large or small.

The record also does not report a comparator group. A before-and-after endpoint in one group, even if its numerical result were available, would describe change during the observation period rather than a controlled difference between OASIS and another approach. Changes over time cannot, in general, be attributed to an intervention solely from an uncontrolled comparison with baseline.

The study’s stated mechanism-of-action purpose and its mention of sequential biopsies describe intended exploration, not a reported mechanistic finding. Biopsy results are not reported in the registry record. Likewise, the adverse-event counts are descriptive and do not establish causal relationships or comparative risks.

The appropriate interpretation is therefore narrow: the registry record describes a single-group wound-area measurement plan and reports limited adverse-event counts, but does not provide numerical primary-outcome results or analyses. It does not support conclusions about treatment effects, comparative performance, or biological mechanism.

13. Why This Trial Matters Statistically

This trial is statistically instructive because the registry record contains detailed endpoint language without a reported endpoint result. It demonstrates the difference between knowing what was intended to be measured and having the estimate, variability, and uncertainty needed to interpret what was observed. A clearly defined outcome is necessary for analysis, but it is not a substitute for the analysis itself.

The design description also highlights why allocation labels need to be read alongside the rest of a record. Allocation is listed as randomized, while the model and arm description identify a single group. Without a described comparator or randomized contrast, the randomized listing cannot be interpreted as evidence of a controlled treatment comparison. Design claims depend on the actual groups and analyses described, not on a single label in isolation.

The endpoint combines a scheduled follow-up limit with wound closure as an earlier stopping point. That definition is important for understanding what the final measurement represents. It also makes clear why reporting follow-up and analysis details matters: readers need to know which subjects reached closure, which contributed a final measurement, and how incomplete measurements were handled. Those details are not reported in the registry record.

Finally, the record separates descriptive safety counts from evidence about causation. Counts of subjects affected are useful context, but without event details and a comparison group they cannot establish comparative safety. Together, these features make the record a useful example of the limits of registry interpretation when outcome estimates and statistical analyses are absent.

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.

Several limitations specific to this record constrain interpretation. The most important is that the primary endpoint is defined but its observed mean decrease and standard deviation are not reported in the registry record. The record also reports zero analyses, so no confidence interval, test, or other inferential result is available.

The described study has one arm, with OASIS Wound Matrix used on all subjects, and no comparator is reported. The registry’s randomized-allocation listing is not reconciled with its single-group model and single-arm description. The record does not explain whether the allocation label reflects a planned feature, a registry entry issue, or some other design detail; none should be inferred.

Enrollment was 13, but the number contributing to the per-protocol endpoint analysis is not reported. The per-protocol designation is not accompanied by inclusion rules, exclusions, completion counts, or missing-data methods. The record does not say how many subjects had wound closure before 12 weeks or how final measurements were handled when data were incomplete.

Although two outcome measures are listed, details for the other outcome are not reported in the registry record. The stated mechanism-of-action purpose refers to sequential biopsy, but biopsy procedures and findings are not reported. Safety reporting is limited to group counts; event terms are not listed for serious events, details for other events are absent, and deaths are recorded as null rather than as a reported count.

These limitations reflect what the registry record documents, not proof that additional information does not exist elsewhere. They mean that this record alone cannot support a detailed assessment of effect size, precision, comparative efficacy, mechanism, or comprehensive safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: OASIS Wound Matrix (Oasis) Mechanism of Action — NCT00570141.
• Registry record last updated 2011-06-09; status last verified 2011-06.
• Results first posted 2010-08-09.
• 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

NCT00570141 is a completed Phase 4 study sponsored by Healthpoint, with a recorded start of 2007-10 and primary completion of 2009-04. Enrollment was 13. The registry describes use of OASIS Wound Matrix in subjects with diabetic foot ulcers or venous stasis ulcers and characterizes the study as single group, with one arm and no masking.

The primary endpoint was mean decrease in wound area from baseline after 12 weeks or wound closure, whichever occurred first, with standard deviation specified. The analysis population was per protocol. Although allocation is listed as randomized, no comparator arm or randomized contrast is described. The primary outcome estimate, statistical analyses, biopsy findings, and details for the other listed outcome are not reported in the registry record.

The adverse-event record lists 0 of 13 subjects affected by serious adverse events and 6 of 13 affected by other adverse events. The death count is not reported.