MIRODERM H2H DFU Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for MIRODERM H2H DFU Study (NCT03232333), a registered phase not stated study. The primary outcome is Percentage of Participants.

2. Clinical Question

3. Trial Design

The MIRODERM H2H DFU Study is a completed study of a biologic wound graft for diabetic foot ulcers. The registry record gives an enrollment of 53, identifies Miromatrix Medical Inc. as the sponsor, and classifies the intervention as a device. The recorded start date is 2017-07-21, and the primary completion date is 2018-09-20. The study summary describes the objective as assessing the ability of MIRODERM to heal difficult diabetic foot ulcers within 12 weeks of treatment.

The record describes the primary outcome population as a per-protocol analysis. It does not state the criteria used to define that population, how participants were allocated, or whether any participants were excluded from that analysis. Allocation is explicitly described as not stated, and the record warns that the arms are not a like-for-like control comparison. The study should therefore not be interpreted as a randomized head-to-head trial.

The registry record lists 7 outcome measures and 3 analyses. It does not report the full analysis plan, the rationale for enrollment, or whether any interim analyses were planned or conducted. The listed enrollment is not the same as a reported primary-outcome denominator: the number included in the per-protocol analysis is not reported in the registry record. These omissions limit what can be concluded about how the study was designed to estimate the primary outcome and how broadly its findings might apply.

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: Per protocol 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 Percentage of Participants, measured over 12 weeks.

The primary endpoint is the percentage of participants with healed ulcers within 12 weeks of treatment. It is a binary outcome at the participant level: a participant is classified according to whether an ulcer met the study’s healing definition within the stated timeframe. The registry description does not give the operational definition of “healed,” so the precise clinical criteria used to classify healing are not reported in the registry record.

A percentage is useful for describing how common an event is in a defined analysis population. It can be easier to interpret than a raw count when the number of participants assessed is known. For a meaningful estimate, both the number meeting the endpoint and the denominator used to calculate the percentage matter. The registry record does not report those primary-outcome values, nor does it report an uncertainty interval. The per-protocol population is named, but its size and membership are also not reported.

As a general statistical point, a confidence interval around a percentage indicates the range of values compatible with the observed data under the method’s assumptions. Without the primary-outcome estimate and its interval, readers cannot assess either the observed frequency of healing or the precision of that estimate from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a binary percentage: the percentage of participants with healed ulcers within 12 weeks. For a binary endpoint, each participant is classified into an outcome category under the study’s definition, and the proportion is calculated from the number with the event and the number assessed. Here, the registry identifies the event and the per-protocol analysis population, but it does not report the event count or the denominator. The primary percentage therefore cannot be reconstructed or checked from the registry record.

What does a confidence interval communicate?

In general, a confidence interval conveys uncertainty around an estimate. For a binary percentage, its width depends in part on the amount of information in the data and on the interval method. A narrow interval indicates greater precision under that method; a wide interval indicates less precision. A confidence interval is not a guarantee that the true value lies in a particular interval, nor does it resolve biases from selection, outcome assessment, or missing data. No interval for the primary healing outcome is reported in the registry record.

What can a p-value establish?

In general, a p-value measures how unusual the observed data would be under a specified statistical model and null hypothesis. It is not the probability that a treatment works, and it does not measure the size or clinical importance of an effect. Interpretation depends on a clearly defined comparison and analysis. The registry record does not report a primary-outcome p-value or identify a tested comparative hypothesis. With no like-for-like control comparison described, a p-value alone would not establish a causal treatment effect.

Why does the analysis population matter?

The primary outcome is assigned to a per-protocol analysis. In general, per-protocol analyses focus on participants who meet protocol-defined conditions, but those conditions can vary across studies. The registry record does not describe the criteria, the number included, or the handling of participants who did not meet them. A per-protocol result can differ from a result based on all participants assigned to a treatment, particularly when protocol adherence or outcome availability is related to prognosis. Those possibilities cannot be assessed from the record.

What is the role of the planning illustration?

The record describes planning assumptions for an illustration based on the observed effect: a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It also says that the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not a description of the study’s actual allocation or its original design. The record explicitly says that this was not a randomized comparison and that allocation was not stated. The illustration should therefore not be read as evidence that participants were allocated equally, that the study used the stated test, or that the study had a particular achieved power.

As a general point, planning calculations depend on assumptions about the target effect, variability, significance level, allocation, and analysis method. If those assumptions do not match the eventual design or data, a planning illustration may not describe the study’s operating characteristics. The record does not report the sample-size justification for the trial’s enrollment, or enough primary outcome information to evaluate a planning calculation against the observed result.

How should the safety summaries be understood?

The registry lists adverse-event counts and affected-participant denominators for the MIRODERM group. For binary adverse-event summaries, the count of participants affected and the number at risk define the descriptive proportion. The record lists serious events for 2 of 53 and other events for 11 of 53; it also lists 0 deaths. These are not estimates of a between-group difference. General statistical comparisons of safety require comparable groups and clear definitions of event collection, follow-up, and attribution. Those details are not reported in the registry record.

The registry gives Diabetic Ketoacidosis and Cellulitis as the top serious-event terms, each with a reported value of 1.9%. Those terms and percentages should be read as the registry’s reported summaries, not as evidence about cause or comparative risk. The record does not report the methods used to select, code, or rank the listed terms.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("MIRODERM")
n      <- c(38)
events <- c(22)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  MIRODERM  38  22  57.9  40.8  73.7  42.2  72.1  42.1  72.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 7 outcome measures and 3 analyses. It does not report which outcomes were designated as secondary, whether analyses were planned in advance, or how many statistical hypotheses were tested. It also does not report a procedure for controlling multiplicity, such as adjusting significance thresholds or interpreting a hierarchy of endpoints. Without that information, the risk of false-positive findings across multiple analyses cannot be assessed.

For general context, testing multiple outcomes or conducting multiple analyses can increase the chance that at least one result appears statistically notable by chance. Adjustment methods can address that issue, but they may also change the interpretation and precision of estimates. No multiplicity adjustment is described in the registry record; this should be treated as information not reported, rather than evidence that no adjustment was used.

The primary analysis population is identified as per protocol, but the record does not describe how missing primary-outcome data were handled. It does not report the number of participants with unavailable outcome assessments, reasons for missingness, or any imputation or sensitivity analyses. Missing outcomes can affect an estimated percentage, particularly if their likelihood is related to healing status. The direction and extent of any effect cannot be determined without the missing-data details.

The record also does not report the per-protocol eligibility rules or how deviations from protocol were managed. Thus, the analysis population cannot be independently characterized from the registry record. Enrollment and the adverse-event denominators do not establish the primary-outcome denominator, which is not reported.

12. 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: diabetic ketoacidosis (1.9%), cellulitis (1.9%).

The registry record lists serious adverse events affecting 2 of 53 participants in the MIRODERM group. Other adverse events are listed as affecting 11 of 53, and deaths are listed as 0. The top serious-event terms are Diabetic Ketoacidosis and Cellulitis, each reported as 1.9%. These are registry summaries and should be read as descriptive counts or percentages, not as evidence that the intervention caused or prevented an event.

The record does not give a like-for-like control comparison, so these figures cannot establish whether the frequency of events was higher or lower than it would have been with another treatment or care approach. It also does not report the timing of events, the criteria used to judge seriousness, the duration of follow-up for safety, or whether events were considered related to the device. The counts should not be combined to infer a total number of affected participants: the record does not state whether participants could appear in more than one category.

In general, safety summaries are easier to interpret when event definitions, follow-up, attribution, and the population at risk are clearly described. Those details are not reported in the registry record. The listed counts therefore provide a limited description of reported safety events, not a complete assessment of comparative safety.

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

The record’s main contribution is to identify the question the study set out to examine: healing of diabetic foot ulcers within 12 weeks after treatment with a biologic wound graft. It identifies a per-protocol primary outcome and reports some adverse-event summaries. However, the primary healing percentage and its uncertainty are not reported in the registry record. Readers cannot determine from this information what proportion of the analysis population had healed ulcers or how precisely that proportion was estimated.

The record also does not describe a randomized comparison or a like-for-like control group. A study outcome among people receiving an intervention is not, by itself, a comparative treatment effect. Even a clearly reported healing percentage would not show how outcomes would compare with another treatment or usual care without an appropriate comparison and analysis. The record does not provide enough information to estimate that contrast.

These limitations do not mean the study had no result or that the intervention had no effect; the registry record simply does not report the primary outcome result needed to evaluate that question. Likewise, adverse-event counts alone do not establish causation, comparative safety, or absence of risk. They describe the entries reported for the listed group and require context about event definitions, follow-up, and attribution.

In general, interpretation of a trial depends on the outcome estimate, its precision, the design and comparison, and the analysis population. Here, the primary outcome result, details of missing data, and the basis for the per-protocol population are not reported. The most defensible reading is therefore limited to the study’s stated aim and the descriptive information recorded, without drawing conclusions about efficacy or comparative safety.

14. Why This Trial Matters Statistically

This study illustrates why an endpoint definition and a numerical result are both needed for statistical interpretation. The registry names a concrete outcome—ulcer healing within 12 weeks—and specifies a per-protocol analysis. Yet without the healing percentage, event count, denominator, or confidence interval, the result’s magnitude and precision cannot be examined. Naming an endpoint does not communicate what the study found.

It also demonstrates the importance of distinguishing a descriptive outcome from a comparative effect. The record states that this was not a randomized comparison, that allocation was not stated, and that the arms were not a like-for-like control comparison. Those design details constrain the conclusions that could be drawn, even if an outcome percentage were available. A treatment effect requires a suitable comparison and methods that support the intended causal interpretation.

The record’s use of a per-protocol analysis raises another broadly important issue: analysis populations must be defined, and exclusions and missing outcomes should be described. Without that information, readers cannot tell who contributed to the primary endpoint or assess whether the analyzed group represents the enrolled population.

Finally, the safety entries show why counts need context. A serious-event count and a reported percentage are useful descriptive information, but they do not establish causality or comparative risk. Clear event definitions, follow-up, attribution, and an appropriate comparison are needed for a fuller safety interpretation. These principles apply broadly to clinical studies, especially when registry summaries contain less detail than a complete statistical report.

15. 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 trial-specific limitations of interpretation follow from what is not reported in the registry record. The primary healing result is absent, as are its numerator, analysis denominator, and uncertainty interval. The operational criteria for calling an ulcer healed are also not described. Without those details, the endpoint cannot be independently evaluated or compared with results defined in other ways.

The record identifies a per-protocol analysis but does not explain how participants qualified for that population, how protocol deviations were handled, or how missing outcome data were treated. It does not report the number of participants with missing primary outcomes or any sensitivity analysis. This leaves uncertainty about the population represented by the primary outcome and about the possible influence of missing data.

The record expressly states that the study was not a randomized comparison, that allocation was not stated, and that arms were not a like-for-like control comparison. A comparative causal interpretation is therefore not supported by the described design. The record also does not report the original sample-size justification or identify whether the planning illustration reflects the trial’s design; it is described as an illustration based on the observed effect, not the trial’s own design.

Although 7 outcome measures and 3 analyses are listed, the registry record does not describe their prespecification, the multiplicity approach, or any interim analysis plan. Safety interpretation is limited by missing detail on event definitions, timing, attribution, and follow-up. These gaps do not establish that procedures were absent; they mean that the relevant information is not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: MIRODERM H2H DFU Study — NCT03232333.
• Registry record last updated 2019-10-22; status last verified 2019-10.
• Results first posted 2019-10-09.
• 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.

19. Record Summary

The MIRODERM H2H DFU Study is recorded as completed and concerns a biologic wound graft for diabetic foot ulcers. The registry lists enrollment of 53, Miromatrix Medical Inc. as sponsor, a start date of 2017-07-21, and a primary completion date of 2018-09-20. Its stated aim was to assess healing within 12 weeks of treatment.

The primary endpoint is the percentage of participants with healed ulcers within 12 weeks, assessed in a per-protocol population. The numerical primary result and its precision are not reported in the registry record. The record states that the study was not a randomized comparison, allocation was not stated, and the arms were not a like-for-like control comparison.

Safety entries list serious adverse events affecting 2 of 53, other adverse events affecting 11 of 53, and 0 deaths. The record lists Diabetic Ketoacidosis and Cellulitis as top serious-event terms, each at 1.9%. These are descriptive entries and do not provide a comparative safety estimate.