Comparative Study of Biologic Mesh Versus Repair With Component Separation.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparative Study of Biologic Mesh Versus Repair With Component Separation. (NCT01295125), a na na study. The primary outcome is The Incidence of Postoperative Hernia Recurrence.

2. Clinical Question

The clinical question as stated is whether recurrence after open ventral hernia repair differs when XenMATRIX biologic mesh is used rather than repair with the patient's own tissue or component separation alone. The registry's wording describes that intended comparison, but the recorded design does not show a randomized or otherwise documented two-arm comparison. Allocation is NA, the model is single-group, and only a XenMATRIX arm description is listed. Those design details limit what can be learned about a contrast between repair strategies from this record.

The primary outcome is clinically relevant to the stated purpose because it concerns whether a hernia returns after repair. The registry specifies a two-year assessment time but gives no operational definition of recurrence, assessment procedure, or outcome results. Other listed outcomes concern postoperative wound events, hospital stay, resource utilization, antibiotic use and days, and resumption of activities of daily living. Their presence indicates a broader set of postoperative questions, but the record reports no analyses for them.

3. Trial Design

The registry identifies the study as NCT01295125 and gives its title as a comparative study of biologic mesh versus repair with component separation. Its official title calls it a pilot study of XenMATRIX biologic mesh versus component separation alone in contaminated ventral hernia repair. The brief summary describes open abdominal incisional hernia repair using XenMATRIX versus repair with the patient's own tissue. These descriptions state the intended comparison; they do not, by themselves, establish how participants were assigned or what comparison was implemented.

The recorded design fields are important to that distinction. Allocation is NA, masking is none, and the model is single-group. The record lists a XenMATRIX arm, but no corresponding comparator arm description. Its design note also indicates that this is not a randomized comparison and that the arms are not a like-for-like control comparison. As a result, the title's comparative language should not be interpreted as evidence of randomized allocation or a documented controlled contrast.

Enrollment is recorded as 9. The registry lists the sponsor as University Hospitals Cleveland Medical Center. The study start is recorded as 2011-01 and primary completion as 2012-05; status is terminated. These entries describe the registry record, but do not explain why the study was terminated or establish when each participant was treated or followed.

The primary outcome is postoperative hernia recurrence at two years after the surgery date. The registry also lists secondary outcomes covering postoperative wound events, length of hospital stay, length of resource utilization, antibiotic usage and days, and resumption of activities of daily living. There are 6 outcome measures recorded, but the registry does not describe the assessment methods for each measure. It records 0 analyses. The primary-outcome population is explicitly marked “No data collected,” so the design information does not yield an outcome estimate.

Phase is recorded as NA. The registry does not report a sample-size justification, an allocation procedure, a detailed protocol, or the reason for termination. Such omissions prevent a fuller assessment of the planned design and of how closely the recorded conduct followed the intended comparison.

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: No data collected

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 The Incidence of Postoperative Hernia Recurrence, measured over two years after surgery date.

The primary endpoint is titled “The Incidence of Postoperative Hernia Recurrence.” Its stated timeframe is two years after the surgery date. In general, an incidence endpoint describes the occurrence of a specified event within a defined period. Recurrence is relevant to the stated hernia-repair question because it concerns whether the hernia returns after surgery.

The registry does not provide a definition of recurrence, the method used to identify it, or the rules for handling recurrence occurring at different times. It also does not describe whether assessments were based on examination, records, participant report, imaging, or another procedure. These details matter because outcome definitions and ascertainment methods determine what counts as an event and how consistently events are detected.

Most importantly, the primary-outcome population is recorded as “No data collected.” No recurrence events, denominator, estimate, or uncertainty measure is reported in the registry record. Therefore, the endpoint is specified as a study question, but the posted record does not show an observed result. The stated follow-up timeframe should not be mistaken for evidence that outcome data were collected through that period.

In general, a time-specific recurrence outcome can help describe the durability of a repair, while a well-defined assessment process supports consistent interpretation. Those general considerations explain why recurrence is a useful outcome to specify; they do not fill in the missing outcome definition or provide a result for this study.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry provides a limited set of design fields and no outcome analyses. The statistical concepts below are general explanations; they do not describe analyses confirmed to have been conducted for this study.

What does an outcome estimate represent?

In general, an outcome estimate is a numerical description of what was observed in the analyzed participants. For a binary event such as recurrence, an estimate might describe the event frequency in a group. An estimate requires both an event definition and the relevant observed data. The registry names recurrence as the primary outcome, but records its population as “No data collected.” It therefore does not provide the event information needed to calculate or interpret an outcome estimate.

Group comparisons require data from groups that can meaningfully be contrasted. The registry describes the intended comparison of XenMATRIX mesh with repair using the patient's own tissue or component separation alone. However, allocation is NA, the model is single-group, and only a XenMATRIX arm description is listed. A comparison named in a study summary is not sufficient to establish the presence of two analyzed groups or a valid estimate of the difference between them.

Why does the design affect interpretation?

In general, random allocation can help balance both measured and unmeasured participant characteristics between treatment groups. When allocation is not randomized, group differences may reflect factors other than the intervention. A controlled comparison also requires clearly defined groups and outcome collection in each group. For this record, the registry does not document random allocation or a like-for-like control comparison. It would therefore be inappropriate to interpret the study title as evidence that these protections were in place.

Masking concerns whether participants, clinicians, outcome assessors, or analysts are kept unaware of assigned treatment. The registry records masking as none. In general, lack of masking can influence care, reporting, or assessment, particularly when an outcome requires judgment. The record does not explain which people knew the treatment or how recurrence was assessed, so the possible role of assessment procedures cannot be evaluated in detail.

What does a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimate under specified assumptions and an analysis plan. A narrow interval indicates greater statistical precision than a wide interval, while an interval that is wide may be compatible with a broad range of underlying values. An interval does not resolve design limitations, measurement problems, or bias. No estimate or confidence interval for recurrence is reported in the registry record, so precision cannot be assessed for the primary outcome.

A significance test, in general, evaluates how compatible observed data are with a specified null hypothesis under a statistical model. A p-value is not the probability that the null hypothesis is true, and it does not by itself describe the size or clinical importance of an effect. No analysis or p-value is reported for this study. The registry's planning assumptions mention a two-sided significance level of 0.05, but this is part of a planning illustration and is not a reported trial result or a documented analysis plan.

What is over-dispersion, and does it apply?

In general, over-dispersion occurs when data vary more than a statistical model assumes. If ignored, uncertainty estimates from some models can be too small, leading to overstated precision. Whether over-dispersion matters depends on the outcome type and the model used. The registry record does not report the outcome data, model, or analysis, so it is not possible to determine whether over-dispersion was relevant or handled.

For time-to-event outcomes, general methods may account for both the timing of events and follow-up that ends before an event is observed. Such analyses require event times and information about censoring. The primary endpoint is described at a two-year timeframe, but no event-time data or censoring rules are reported. The registry does not establish that a time-to-event analysis was conducted.

How should planning illustrations be read?

In general, a sample-size calculation asks how much information a future study might need to detect a specified effect under chosen assumptions. The registry describes planning illustrations based on an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect, and distinguishes total events for time-to-event illustrations from participants per arm for other illustrations.

These are explicitly planning illustrations, not the trial's own design. Their assumptions do not show that the study enrolled or analyzed the indicated participants, nor that it had any particular probability of detecting an effect. Sample-size calculations are not observed power. The registry does not report a sample-size justification for the trial, and it supplies no recurrence result from which to judge the relationship between an observed effect and a planning assumption.

More generally, statistical methods need to be matched to the outcome, study design, and available data. A binary outcome, a count, a continuous measure, and a time-to-event outcome may require different estimands and models. The record names several outcome domains but does not state their variable definitions, analysis populations, or planned methods. With 0 analyses recorded, there is no basis for attributing a specific statistical model, adjustment, or inferential procedure to the study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 6 outcome measures. It identifies postoperative hernia recurrence as the primary outcome and lists secondary outcomes concerning wound events, hospital stay, resource utilization, antibiotic usage and days, and resumption of activities of daily living. The registry does not explain how the primary and secondary outcomes were prioritized for inference, or whether any were exploratory.

In general, testing multiple outcomes can increase the chance of obtaining at least one apparently notable result by chance. Statistical plans may address this issue by specifying a primary endpoint, defining a testing sequence, or adjusting inference across outcomes. The registry does not report a multiplicity strategy or a statistical analysis plan. Because it records 0 analyses, there are no reported tests to evaluate for multiplicity.

Missing-data handling is also not reported in the registry record. The primary-outcome population is explicitly described as “No data collected,” which is different from a report of observed outcomes with some participants missing follow-up. The record does not state whether outcome collection began, whether participants were followed to the specified timeframe, or how incomplete assessments would have been handled.

The registry does not define an analysis population, such as participants assigned to a group, treated, or with outcome measurements. It also does not provide participant flow or explain whether enrollment corresponds to the population eligible for each outcome. These omissions prevent assessment of exclusions, attrition, or the relationship between enrollment and analysis.

In general, a statistical analysis plan helps establish outcome definitions, populations, missing-data procedures, and the handling of multiple comparisons before results are interpreted. Without those details and without posted analyses, neither the risk of selective reporting nor the effects of missing data can be assessed for this record.

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

The record documents a study intended to examine XenMATRIX biologic mesh in ventral hernia repair and identifies recurrence two years after surgery as its primary outcome. It also records enrollment of 9, a single-group model, allocation as NA, masking as none, and terminated status. These registry entries describe the registry entry; they do not provide evidence about the frequency of recurrence or the relative outcomes of different repair strategies.

The primary outcome is marked “No data collected,” and the record lists 0 analyses. There is therefore no posted estimate of recurrence, no confidence interval, and no statistical comparison to interpret. This absence should not be read as a finding of no recurrence or no difference. It means that the registry record does not report outcome data with which to determine either.

The stated comparative purpose also does not establish that a comparison was carried out. The registry's single-group model and XenMATRIX arm description, together with the absence of a like-for-like control comparison, limit what can be concluded about component separation alone. The title and summary express the intended question, but they cannot substitute for recorded group definitions and results.

The listed secondary outcomes indicate additional topics of interest, but no results are reported for them. Similarly, the terminated status does not explain the reason the study ended, whether follow-up was completed, or whether termination affected data collection. Those interpretations are not reported in the registry record.

In general, a clinical study can be informative even when it does not produce a comparative effect estimate, for example by documenting feasibility or identifying the need for clearer outcome procedures. However, this record does not report such findings either. Its statistical meaning is therefore chiefly descriptive: it records a clinical question and design information, while leaving the outcome question unanswered in the posted results.

12. Why This Trial Matters Statistically

This trial matters statistically because its intended comparative question and its recorded design do not align cleanly. The title and summary describe XenMATRIX mesh versus repair with the patient's own tissue or component separation alone. Yet the registry records a single-group model, allocation as NA, and a XenMATRIX arm without a corresponding comparator arm description. Recognizing this difference is essential before treating the record as evidence from a controlled comparison.

The record also illustrates the distinction between enrollment and analyzable outcome information. Enrollment is recorded as 9, but the primary-outcome population is marked “No data collected,” and 0 analyses are recorded. An enrollment figure alone cannot establish an outcome denominator, follow-up completeness, or precision. Without observed data, the primary question cannot be answered statistically from this registry entry.

In general, clear outcome definitions and analysis plans are important for interpreting clinical research. The primary endpoint names recurrence and gives a two-year timeframe, but the registry does not describe how recurrence was defined or ascertained. Such details affect comparability and the meaning of any future estimate. The record also lists several secondary outcomes without reporting how they were analyzed or how multiple outcomes were handled.

Finally, planning calculations and trial results serve different purposes. The record characterizes its sample-size assumptions as planning illustrations rather than the trial's own design. That distinction helps prevent a planning quantity from being mistaken for evidence about the study's actual precision, power, or results. Here, the registry's statistical value lies in revealing what design information is recorded and what outcome evidence is absent.

13. 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 consequential limitation of the registry record is the absence of collected primary-outcome data. Recurrence is named as the primary endpoint, but its population is recorded as “No data collected.” No event count, estimate, denominator, or uncertainty measure is available. The record also lists 0 analyses, so no statistical outcome finding can be evaluated.

The intended comparison is not reflected in a documented two-arm design. Allocation is NA and the model is single-group. The registry lists a XenMATRIX arm but does not provide a corresponding comparator arm description; the record also notes that this is not a randomized comparison and that the arms are not a like-for-like control comparison. The comparative title and summary therefore should not be treated as proof of a valid comparative analysis.

Outcome measurement details are limited. Although recurrence is tied to two years after surgery, the registry does not define recurrence or describe how it was assessed. It does not report the status of follow-up, outcome-specific populations, or missing-data procedures. The secondary outcomes are listed but have no reported analyses.

The registry marks the study terminated but does not give the reason for termination. It also does not report the protocol's sample-size justification, detailed statistical plan, interim analyses, or multiplicity strategy. These absences restrict assessment of study conduct and analytic choices. The enrollment figure cannot resolve these uncertainties or establish how many participants contributed usable data.

These limitations apply to what the registry record reports. They do not establish why the data are absent or whether additional information exists outside the record.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Comparative Study of Biologic Mesh Versus Repair With Component Separation. — NCT01295125.
• Registry record last updated 2023-01-25; status last verified 2023-01.
• Results first posted 2023-01-25.
• 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.

17. Record Summary

NCT01295125 is a terminated study sponsored by University Hospitals Cleveland Medical Center. The registry records enrollment of 9, a study start of 2011-01, primary completion of 2012-05, masking as none, allocation as NA, and a single-group model. Its stated purpose is to compare open abdominal ventral hernia repair using XenMATRIX biologic mesh with repair using the patient's own tissue or component separation alone.

The primary outcome is postoperative hernia recurrence two years after surgery. The registry records its population as “No data collected” and lists 0 analyses. Six outcome measures are recorded, including secondary outcomes relating to wound events, hospital stay, resource utilization, antibiotic use and days, and activities of daily living. The record does not provide a recurrence result or results for the secondary outcomes.

The record's design fields do not document a randomized, like-for-like comparison. It does not report the reason for termination, a detailed analysis plan, or the sample-size justification. The posted information therefore describes the study's question and selected design features, but does not provide evidence to estimate or compare clinical outcomes.