Post Market Study of Parietene™ DS Composite Mesh in Ventral Hernia Repair: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Post Market Study of Parietene™ DS Composite Mesh in Ventral Hernia Repair (NCT03495154), a na na study. The primary outcome is Number of Participants With Hernia Recurrence Within 12 Months Following Parietene™ DS Composite Mesh Use in Ventral Hernia Repair.

2. Clinical Question

3. Trial Design

This was a multicenter, prospective, post-market, single-arm study of Parietene™ DS Composite Mesh in subjects undergoing ventral hernia repair. The registry lists the study as completed, with enrollment of 145. Its recorded start date is 2018-06-21 and its primary completion date is 2021-07-21. The listed condition is ventral hernia, and the sponsor is Medtronic - MITG.

The registry identifies one intervention group: patients treated with Parietene DS Composite Mesh. The study model is single group. Allocation is listed as NA, and masking is listed as none. These entries describe a design without a randomized allocation between mesh and a comparator treatment. Consequently, the results characterize the participants in the study group rather than estimating a contrast against a concurrent control group.

The brief summary describes the objective as confirming safety and performance at short-term follow-up of 1 and 3 months, mid-term follow-up of 12 months, and long-term follow-up of 24 months. Secondary outcomes include adverse device effects at intraoperative and postoperative time points, as well as hernia recurrence at 1, 3, and 24 months. The primary endpoint is recurrence within 12 months.

The registry lists phase as NA. It does not report the eligibility criteria, the details of recruitment, the number of participating centers, or the particular surgical approaches used. The record also does not describe procedures for outcome adjudication or indicate whether follow-up assessments were conducted using a standardized protocol. Those details should not be inferred from the prospective, multicenter design label alone.

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: Hernia recurrence rate at 12M changed from what was previously reported, 4 (3.5%) due to data imputed for hernia recurrence. It was assumed subjects who missed the 12M visit and had no recurrence at 24M also had no recurrence at 12M, as hernias cannot appear and then disappear over time without treatment. There were 5 subjects excluded from the primary endpoint analysis due to not completing the 12M/24M visits and therefore, unable to determine if a recurrence occurred in these subjects.

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.

Population: Post Market Study of Parietene™ DS Composite Mesh in Ventral Hernia Repair Approximately 125 Subjects

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Hernia Recurrence Within 12 Months Following Parietene™ DS Composite Mesh Use in Ventral Hernia Repair, measured over 12 months post surgery.

The primary endpoint counts participants with hernia recurrence within 12 months following Parietene™ DS Composite Mesh use in ventral hernia repair. Its unit is participants, and the stated timeframe is 12 months after surgery. This is a binary participant-level outcome for each person: recurrence is either recorded or not recorded for the specified period, and the group result is expressed as a count.

General: a recurrence endpoint addresses whether the condition being repaired is recorded again during a defined follow-up period. A fixed follow-up period makes the timing of outcome assessment explicit, which is important because recurrence may be observed differently when participants are followed for different lengths of time. A participant count is also distinct from an event count: it describes people with recurrence, not necessarily the number of recurrence episodes.

The registry description says the 12-month recurrence rate changed from a previously reported 4 (3.5%) because data were imputed for hernia recurrence. It states that participants who missed the 12-month visit and had no recurrence at 24 months were assumed to have no recurrence at 12 months. This assumption is material to interpreting the reported endpoint. The registry record does not give the full endpoint definition, the number of participants whose status was imputed, or the original and updated analysis details beyond this description.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a prospective, multicenter study with a single group treated with Parietene DS Composite Mesh. A single-arm design can describe outcomes among participants who received the intervention. Without a concurrent comparison group, it does not provide a randomized estimate of how outcomes would differ under another treatment or under no use of the device. Factors other than the intervention, including participant characteristics and clinical care, cannot be separated from the observed results through a between-arm comparison.

What does a participant count represent?

The primary endpoint is a count of participants with hernia recurrence within 12 months following surgery. A participant-level count records people meeting the endpoint rather than the total number of recurrence episodes. The accompanying percentage, 3.5%, gives a proportional description in the registry. The record does not specify in the available endpoint details the denominator used for that percentage or give a complete account of the endpoint assessment procedure, so those details should not be reconstructed.

How should the imputation be understood?

The registry says that the 12-month recurrence result changed from a previously reported 4 (3.5%) due to imputed recurrence data. Specifically, the description says participants who missed their 12-month visit and had no recurrence at 24 months were assumed to have no recurrence at 12 months. Imputation fills in an outcome that was not observed directly using an assumption or model. Here the stated assumption uses later recurrence status to assign an earlier status for some participants.

That choice affects what the 12-month count represents: it includes a status assigned under the stated rule, not only statuses observed at the 12-month visit. The registry record does not report the number of missing visits, the number of imputed outcomes, any alternative imputation assumptions, or a sensitivity analysis. It also does not provide enough detail to assess the robustness of the primary result to the assumption.

What does statistical precision mean?

General: an estimate based on a study group is subject to sampling uncertainty. A confidence interval is a range calculated using a statistical method to express uncertainty around an estimate. A narrower interval generally indicates greater precision under that method, while a wider interval indicates more uncertainty. No confidence interval for the primary recurrence result is reported in the registry record for this analysis, so its precision cannot be characterized numerically beyond the reported count and percentage.

General: statistical significance tests, when used, evaluate compatibility between observed data and a specified null hypothesis under assumptions. A p-value does not measure the probability that a treatment is effective or that the null hypothesis is true. The registry record does not report a primary-endpoint p-value or a formal hypothesis test. No conclusion about statistical significance should therefore be inferred from the endpoint count alone.

Why does the design affect interpretation?

With one intervention group, observed recurrence and adverse-event counts are descriptive. The study does not have a control-arm contrast from which to estimate a relative effect. A before-and-after or historical comparison is not reported in the registry description, and no such comparison should be presumed. The study's prospective and multicenter labels describe how it was organized, but do not remove the limitations of having no concurrent comparator.

General: over-dispersion matters when count data vary more than a statistical model expects. It can make standard errors too small if a model assumes less variability than the data contain. The primary endpoint is a participant count for a binary outcome, not a reported repeated count outcome with a dispersion estimate. The registry record does not report an over-dispersion assessment or a model for the primary endpoint, so no such method can be attributed to this study.

How should planning illustrations be read?

The stated planning illustration assumptions use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. The sample sizes are planning illustrations computed from the observed effect, not the trial's own design. They are not observed power. The single-arm study itself did not include equal allocation between two treatment arms, so those assumptions describe a hypothetical planning exercise rather than the observed study design.

General: power is a design-stage probability of detecting an effect of a prespecified size under specified assumptions. A calculation using an effect observed after a study is not a measure of the study's achieved power. Such a calculation is also sensitive to the chosen effect size and assumptions. The registry record does not report a prospective sample-size justification, the effect the original investigators planned to detect, or the statistical methods used for the primary endpoint.

The registry lists 145 enrolled participants and a safety group of 125 at risk. Those figures are not interchangeable: the record does not explain the difference in the available description. The endpoint-specific analysis population and the treatment of all participants in the primary analysis are not reported. Consequently, the count and percentage should be read with the stated imputation caveat and without assuming an unreported analysis population or denominator.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple outcomes, including the primary 12-month hernia-recurrence endpoint, adverse device effects assessed at several time points, and recurrence at 1, 3, and 24 months. Evaluating multiple outcomes or time points raises a general multiplicity issue: when many statistical tests are performed, the chance of at least one apparently notable result can increase. The registry record does not report whether formal tests were conducted, whether any multiplicity adjustment was used, or which outcomes were included in any testing hierarchy.

Missing data are directly relevant to the primary endpoint. The registry description states that the 12-month recurrence result changed from a previously reported 4 (3.5%) after imputation. It says that participants missing the 12-month visit who had no recurrence at 24 months were assumed to have no recurrence at 12 months. The number of participants affected, the extent of missingness at other time points, and the methods for handling missing safety outcomes are not reported in the registry record.

The registry record also does not describe the primary analysis population, whether all enrolled participants were included in each outcome analysis, or the handling of withdrawals and incomplete follow-up. It does not report sensitivity analyses to assess the imputation assumption. These omissions limit assessment of how dependent the recurrence result is on the analysis population and the treatment of missing observations.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hypoxia (2.4%), ileus (2.4%), abdominal hernia (1.6%), abdominal pain (1.6%), postoperative ileus (1.6%).

The safety group lists 125 participants at risk, 29 affected by serious adverse events, 20 affected by other adverse events, and 2 deaths. These are counts for the single mesh group, not comparative estimates. The registry also lists serious-event terms and percentages: Hypoxia, 2.4%; Ileus, 2.4%; Abdominal Hernia, 1.6%; Abdominal Pain, 1.6%; Postoperative Ileus, 1.6%; and Atrial Fibrillation, 0.8%.

These figures describe events recorded in the study; they do not by themselves establish that an event was caused by the mesh. The registry record does not report whether the deaths were related to the device or procedure, nor does it provide the causes of death in the registry entries. It also does not describe the criteria used to classify an event as serious or provide details on duration, severity, or clinical course.

Event categories or terms may overlap, so the listed counts or percentages should not be added to infer a total number of affected participants. The available information does not clarify overlap among the serious-event terms. Without a control group, the counts cannot be used to compare safety-event frequency with another treatment group.

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

The posted results describe a completed single-arm study of Parietene™ DS Composite Mesh in ventral hernia repair. The primary endpoint concerns participants with recurrence within 12 months, and the registry description gives 4 (3.5%) while noting that the result changed after imputation. The safety information lists serious and other adverse-event counts and two deaths in the mesh group. Together, these details characterize outcomes recorded or assigned under the described missing-data rule in this study.

They do not establish a causal effect of the mesh on recurrence or adverse events. There is no comparator group, and the registry record does not report a randomized contrast. The results therefore cannot show how the observed outcomes would compare with outcomes under another device, another repair approach, or no use of this mesh. They also should not be read as proof that an outcome was caused by or prevented by the device.

The recurrence result requires particular care because the registry says that participants missing the 12-month visit but without recurrence at 24 months were assumed to have no recurrence at 12 months. This means the reported endpoint includes an imputation assumption. The number of affected participants and the results under alternative assumptions are not reported, so the sensitivity of the result to missing-data decisions cannot be assessed from the registry record.

The registry entries do not report a confidence interval for recurrence, a formal statistical test, or a complete account of the analysis population. Thus, the precision and broader generalizability of the result are uncertain from these registry entries alone. A count and percentage are useful descriptive summaries, but they do not independently answer questions about comparative effectiveness or establish what outcomes might occur in a different clinical population.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of what a prospective, single-arm post-market design can and cannot describe. It records outcomes after use of a device over planned follow-up periods, and includes a primary recurrence endpoint and safety outcomes. Such information can characterize observed experience in the enrolled group, while the lack of a concurrent comparator constrains causal and comparative interpretation.

The primary endpoint also illustrates how missing-data decisions can influence an outcome. The registry explicitly states that the 12-month result changed after data were imputed, and describes an assumption based on recurrence status at 24 months for participants who missed the 12-month visit. Reporting that rule is important because the endpoint is not simply a count of directly observed 12-month outcomes. The absence of the number imputed and of sensitivity analyses leaves uncertainty about the impact of the assumption.

The difference between enrollment of 145 and the safety group of 125 at risk is another statistical consideration. The registry record does not explain this difference in the available description. Understanding which participants contributed to each analysis, and why, is important when interpreting counts and percentages. The record also does not report a confidence interval for the primary endpoint, so the precision of the estimate cannot be assessed in the usual interval-based way.

Finally, planning calculations based on an observed effect are distinct from prospective design justification and observed power. The listed assumptions describe a hypothetical two-arm planning exercise, while the study itself was single arm. Keeping those roles separate helps prevent planning illustrations from being mistaken for results of the trial's original statistical design.

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 study has no concurrent comparator group. Its single-arm design supports descriptive reporting of outcomes among participants treated with Parietene DS Composite Mesh, but does not provide a like-for-like treatment comparison. The registry record does not report randomization or masking; allocation is listed as NA and masking as none.

The primary recurrence result depends on imputation for some participants. The registry states that participants who missed the 12-month visit and had no recurrence at 24 months were assumed to have had no recurrence at 12 months. It does not report how many participants were assigned outcomes this way, the extent of missing follow-up, or whether alternative assumptions were tested. This limits assessment of the result's sensitivity to missing data.

The record lists enrollment of 145, while the safety group lists 125 at risk. The reason for this difference and the analysis populations for the primary and secondary outcomes are not reported in the registry record. The registry entries also do not include a confidence interval for the primary endpoint, a formal test, a sample-size justification, or the detailed statistical analysis plan. The registry does not report outcome-adjudication procedures or the detailed definitions used for recurrence and adverse-event classifications.

Safety counts lack a concurrent benchmark, and the available details do not establish whether events or deaths were related to the device. The registry lists follow-up outcomes at multiple times, but does not report how multiplicity was handled. These limitations restrict conclusions to the descriptive findings and assumptions recorded for this study.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Post Market Study of Parietene™ DS Composite Mesh in Ventral Hernia Repair — NCT03495154.
• Registry record last updated 2024-04-23; status last verified 2024-04.
• Results first posted 2022-11-17.
• 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

NCT03495154 is a completed, multicenter, prospective, post-market, single-arm study of Parietene™ DS Composite Mesh in ventral hernia repair. The registry lists enrollment of 145, a start date of 2018-06-21, and primary completion on 2021-07-21. Allocation is NA and masking is none.

The primary endpoint is the number of participants with hernia recurrence within 12 months after surgery. The registry description reports 4 (3.5%) and says the result changed after imputation for participants missing the 12-month visit who had no recurrence at 24 months. The safety group lists 125 participants at risk, 29 affected by serious adverse events, 20 by other adverse events, and 2 deaths. No concurrent comparator is reported, so the results are descriptive rather than a treatment contrast.