This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Peri-Strips Dry (PSD) Veritas Collagen Matrix Staple Line Reinforcement for Colorectal Surgery (NCT00559013), a na na study. The primary outcome is Number of Participants With Major Colorectal Related Adverse Events: Leak, Stricture and Hemorrhage..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00559013 |
| Phase | NA |
| Condition | Colorectal Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 38 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Baxter Healthcare Corporation |
| Results posted | Yes |
2. Clinical Question
Population
The registry record identifies colorectal cancer as the condition and lists an enrollment of 38. It does not describe the enrolled participants’ clinical characteristics, eligibility criteria, or the types of colorectal procedures in enough detail to characterize the study population further. Those details are not reported in the registry record.
Intervention
The intervention is a device described as staple-line reinforcement using PSD Veritas Collagen Matrix. The aim in the brief summary is to assess its utility in minimizing the risk of leakage during or after colorectal surgery. The record does not provide further procedural details about how the reinforcement was applied.
Comparator
The record describes a single-group study, with one listed arm: PSD Veritas Collagen Matrix Reinforcement Arm. It does not identify a control arm or a randomized comparison. As a result, the record does not support a direct comparison with another treatment or with no reinforcement.
Primary question
The listed primary outcome is the number of participants with major colorectal-related adverse events—leak, stricture and hemorrhage—at discharge and 1 Month post surgery. The clinical question is therefore whether and how often these events were recorded among participants receiving the reinforcement. The registry record does not report the outcome count or an analysis of that question, so the result cannot be characterized from the posted information.
3. Trial Design
This was a completed, single-group device study listed under the title Peri-Strips Dry (PSD) Veritas Collagen Matrix Staple Line Reinforcement for Colorectal Surgery. Baxter Healthcare Corporation is named as the sponsor. The registry lists enrollment of 38, a start date of 2007-03 and primary completion in 2008-12. Phase is listed as NA.
The study model is single group. One arm is described: PSD Veritas Collagen Matrix Reinforcement Arm. Allocation is listed as NA and masking as NONE. These registry entries do not describe a randomized allocation process or masking, and the record explicitly identifies the study as not being a randomized comparison. The arm therefore has no like-for-like control group in the posted design.
The intervention is categorized as a device and named Staple line reinforcement. The brief summary describes the purpose as assessing the utility of PSD Veritas as reinforcement intended to minimize the risk of leakage during or after colo-rectal surgery. The record does not provide a fuller account of the operative procedure, participant selection, treatment delivery, or follow-up procedures; those details are not reported in the registry record.
The registry lists one outcome measure and zero analyses. The primary outcome is a participant count for major colorectal-related adverse events, with the timeframe stated as discharge and 1 Month post surgery. Although the study status is completed, a completion status alone does not provide the missing outcome result or explain how data were analyzed. The record does not report a statistical analysis plan, sample-size justification for the original study, or information about interim analyses.
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: Subjects were excluded from the study if the met any of the exclusion criteria including having a a body mass index greater than 35, a history of Chron's Disease, or stage IV cancer. There was no washout, run-in or transition period to this study.
Overall Study
| Stage | PSD Veritas Collagen Matrix Reinforcement Arm |
|---|---|
| STARTED | 38 |
| COMPLETED | 38 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | PSD Veritas Collagen Matrix Reinforcement Arm |
|---|---|---|
| Participants analysed | 38 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 27 |
| Age, Categorical: >=65 years | Participants | 11 |
| Age, Continuous | years | 57.26 (SD 11.44) |
| Sex: Female, Male: Female | Participants | 18 |
| Sex: Female, Male: Male | Participants | 20 |
| Region of Enrollment: United States | participants | 38 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Major Colorectal Related Adverse Events: Leak, Stricture and Hemorrhage., measured over Discharge and 1 Month post surgery.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is titled “Number of Participants With Major Colorectal Related Adverse Events: Leak, Stricture and Hemorrhage.” Its unit is participants, and its timeframe is discharge and 1 Month post surgery. In practical terms, the stated endpoint is intended to count participants who experienced an event in the named group of colorectal-related complications during the stated assessment period. It is not a measure of event severity, duration, or time until an event.
General statistical context: An endpoint that records whether participants experienced an event is commonly treated as a binary outcome at the participant level: each participant either meets the event definition or does not. A count of participants can then describe how many meet that definition within the analyzed group. The precise operational rules matter—for example, how the listed event types were defined and how events spanning the assessment times were handled—but those details are not reported in the registry record.
The endpoint is clinically relevant to the study’s stated purpose because leakage is named in the brief summary, and the primary outcome includes leak along with stricture and hemorrhage. However, the posted results do not give the number of participants meeting the primary endpoint, separate counts for its event types, or an uncertainty estimate. The registry record therefore states what was to be measured but does not show the result for that endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a single-group study of PSD Veritas Collagen Matrix staple-line reinforcement, with enrollment of 38. Its primary outcome is the number of participants with leak, stricture or hemorrhage at discharge and 1 Month post surgery. These details identify the population structure, intervention and planned outcome at a high level. They do not establish the frequency of the primary outcome, because no primary outcome result is reported in the registry record.
The record’s adverse-event information is separate from a reported analysis of the primary endpoint. In the PSD Veritas Collagen Matrix Reinforcement Arm, 38 participants are listed as at risk for serious adverse events, with 3 affected; 38 are listed as at risk for other adverse events, with 2 affected. The serious adverse-event terms listed include Anastomotic Buttress Leak at 7.9% and Bleeding at 2.6%. These are descriptive safety entries. The record does not explain their relationship to the primary endpoint, provide event-specific counts for the primary outcome, or report an inferential comparison.
General statistical context: A proportion or count from a single group describes what was recorded in that group under the stated definitions and follow-up. Without a comparison group, it cannot by itself isolate the effect of the intervention from other explanations, such as underlying risk or features of the surgery. This is particularly important when the question concerns whether an intervention reduces risk: a reduction requires a suitable reference for comparison, and the registry record does not describe one.
No confidence interval, p-value, effect estimate, or primary-outcome analysis is reported. That means the precision of the primary outcome estimate cannot be assessed from the registry record. Even a reported count would not, by itself, show how uncertain the underlying event frequency might be; a confidence interval would ordinarily help express that uncertainty. No such interval is listed for the primary endpoint.
The study is marked completed, but completion does not remedy the absence of posted endpoint results. Nor does the adverse-event information answer the primary question on its own. The appropriate reading is limited to the design and descriptive safety entries that the registry reports. The record does not support a conclusion that the reinforcement increased or decreased the risk of the primary events.
9. Statistical Methods Explained
The registry record identifies a single-group design and lists a participant-count endpoint. It does not report the statistical methods used to analyze the primary outcome. The explanations below describe general statistical concepts; they should not be read as a claim that any particular method was used in this study.
What does a participant count represent?
For an outcome defined by whether a participant experiences an event, a participant-level count records how many people meet the event definition in the analyzed group. To interpret such a count, readers need both the count and a clearly specified denominator, together with the event definition and assessment period. The registry record states the endpoint’s unit and timeframe, but does not report its result or give operational definitions for leak, stricture and hemorrhage.
A count of participants is not necessarily the same as a count of events. One participant might experience more than one event, depending on the outcome rules. The primary outcome title refers to participants, but the registry does not say how overlapping event types were handled. It would therefore be inappropriate to infer the number of individual events from a participant count, or vice versa.
What would a confidence interval add?
General statistical context: A confidence interval expresses uncertainty around an estimated quantity. For an event proportion, it indicates a range of values compatible with the observed data under the method’s assumptions. It does not remove uncertainty, and it is not a guarantee that the true value lies in the interval. The width depends on the amount of information in the data and on the interval method.
No confidence interval or primary-outcome estimate is reported in the registry record. Consequently, readers cannot judge the precision of the primary result from the posted information. The presence of enrollment information does not substitute for an outcome estimate: the observed number meeting the endpoint is also needed to characterize the result.
Why does the comparison structure matter?
General statistical context: A comparison between groups can help distinguish differences associated with an intervention from the background frequency of an outcome. Random assignment, when used and adequately implemented, can help make groups comparable on average. A single-group study has no concurrent control group for this purpose. Its observed event frequency can be described, but it cannot establish what would have occurred in a comparable group without the intervention.
This registry record labels the model SINGLE GROUP and identifies no randomized comparison. It therefore does not support a comparative treatment-effect estimate. The allocation entry is NA, and the masking entry is NONE. The record does not describe further design or analysis methods that would change this basic limitation.
What can a p-value tell a reader?
General statistical context: A p-value assesses how unusual data would be under a specified null hypothesis and statistical model. It does not measure the size or clinical importance of an effect, and it does not give the probability that a hypothesis is true. Interpretation depends on knowing the tested hypothesis, analysis method, and how the result was selected.
No p-value or hypothesis test for the primary endpoint is reported. The registry lists zero analyses, so there is no posted analysis result to interpret. It would not be appropriate to reconstruct a test from the posted safety entries or to treat those entries as an analysis of the primary outcome.
How should planning calculations be read?
The stated sample-size illustration is a planning exercise based on the observed effect, not the design basis of this trial. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. Any resulting sample-size values are planning illustrations, not observed power. They do not turn the single-group study into a two-arm comparison, and they are not evidence of the trial’s original sample-size justification.
The record does not report the original study’s sample-size justification or the details needed to evaluate the planning illustration’s effect estimate. In general, planning calculations depend on assumptions about the target effect, variability or event frequency, significance threshold, allocation, and analysis. If those assumptions differ from the eventual study or are uncertain, the calculated sample size may not describe the precision of the result actually obtained. The registry record does not provide a primary endpoint estimate from which to assess that relationship.
More broadly, no statistical model, adjustment strategy, missing-data method, or analysis population is reported. These omissions prevent readers from checking the assumptions behind an inferential result, because no inferential result is posted, and from determining exactly which participants would have contributed to the primary outcome analysis.
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.
| Arm | Participants | Events | Observed % | Clopper-Pearson 95% CI | Wilson 95% CI | Bayesian 95% credible interval |
|---|---|---|---|---|---|---|
| PSD Veritas Collagen Matrix Reinforcement Arm | 38 | 4 | 10.5% | 2.9% to 24.8% | 4.2% to 24.1% | 4.3% to 24.2% |
R code and output
arm <- c("PSD Veritas Collagen Matrix Reinforcement Arm")
n <- c(38)
events <- c(4)
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 PSD Veritas Collagen Matrix Reinforcement Arm 38 4 10.5 2.9 24.8 4.2 24.1 4.3 24.211. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and zero analyses. The listed primary outcome is the number of participants with major colorectal-related adverse events—leak, stricture and hemorrhage—at discharge and 1 Month post surgery. The record does not report a result for that outcome or explain whether the listed event types were analyzed together, separately, or in another way.
General statistical context: Multiplicity arises when several outcomes, time points, subgroups, or statistical tests are examined. The more opportunities there are to identify a nominally unusual result, the greater the chance that at least one may appear notable by chance. A prespecified analysis plan and, where appropriate, a multiplicity adjustment can help clarify how multiple tests are handled. The registry record does not report whether such a plan or adjustment was used. A count of one listed outcome measure does not establish how many analyses were planned or performed.
The record also does not report missing primary-outcome data, participant flow through follow-up, or how missing observations were handled. It does not define an analysis population, such as whether every enrolled participant was included or whether exclusions were made. These omissions matter because event counts and denominators can depend on who was observed and how missing status was treated.
Accordingly, neither multiplicity handling nor missing-data handling can be evaluated from the registry record. The absence of these details should not be interpreted as proof that no multiplicity or missingness occurred; their status is not reported in the registry record.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| PSD Veritas Collagen Matrix Reinforcement Arm | 3 | 38 | 7.9% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| PSD Veritas Collagen Matrix Reinforcement Arm | 2 of 38 |
Most frequent serious adverse event terms
| Event term | Organ system | PSD Veritas Collagen Matrix Reinforcement Arm |
|---|---|---|
| Anastomotic Buttress Leak | Surgical and medical procedures | 3 of 38 |
| Bleeding | Surgical and medical procedures | 1 of 38 |
Most frequent non-serious adverse event terms
| Event term | Organ system | PSD Veritas Collagen Matrix Reinforcement Arm |
|---|---|---|
| Post operative ileus | Surgical and medical procedures | 2 of 38 |
Serious events with the highest arm-level rate: anastomotic buttress leak (7.9%), bleeding (2.6%).
The registry’s safety entries list the PSD Veritas Collagen Matrix Reinforcement Arm with 38 at risk for serious adverse events and 3 affected. For other adverse events, it lists 38 at risk and 2 affected. The record also names Anastomotic Buttress Leak at 7.9% and Bleeding at 2.6% among the top serious terms. These entries should be read as the registry’s descriptive safety information, not as a comparison between treatments.
The record does not say whether the people affected in the serious and other adverse-event categories overlap. The counts should not be added to estimate a number of distinct participants. It also does not provide event-specific denominators, timing, severity grades, or a detailed definition of the listed terms. Deaths are not reported in the registry record.
The safety terms are not a substitute for the primary endpoint result. Although leakage is relevant to the study’s stated purpose and a leak term appears in the serious-event listings, the registry does not report how the safety term maps to the primary endpoint definition. The percentages for serious-event terms should not be treated as evidence of a treatment effect or as a comparison with an untreated group.
13. What the Result Does, and Does Not, Mean
The record establishes that the study evaluated PSD Veritas collagen matrix staple-line reinforcement in colorectal surgery using a single-group design. It lists enrollment of 38, names the primary outcome and its assessment timeframe, and provides descriptive adverse-event entries. Those details can guide a reader’s understanding of what the registry intended to assess and what safety information it posted.
The record does not report the primary outcome count, an estimate of event frequency, a confidence interval, or a statistical test. Therefore, it does not show how many participants experienced leak, stricture or hemorrhage under the primary endpoint definition, nor how precise any estimate would be. The listed serious and other adverse-event counts do not fill this gap because they are not reported as the primary endpoint analysis.
General statistical context: Observing an event frequency in a group is not equivalent to estimating the causal effect of an intervention. A causal comparison requires a reference that represents what would have happened to a comparable population without the intervention, subject to design and analysis assumptions. This study is listed as single group and not randomized, so a comparative effect cannot be derived from the registry record.
The record also does not establish whether the intervention reduced, increased, or left unchanged the risk of the named complications. Such statements would go beyond the posted evidence. The appropriate conclusion is narrower: the registry describes the study design, the intended primary endpoint and some safety counts, but does not report the primary outcome result or a comparative analysis.
Missing information is not evidence that no events occurred, that the endpoint was not measured, or that a particular analysis was performed. It means only that these details are not reported in the registry record. Readers should distinguish the existence of a completed study record from the availability of results adequate to answer the primary clinical question.
14. Why This Trial Matters Statistically
This study is statistically notable for the gap between a clearly named clinical question and the limited results information in the registry record. The primary endpoint targets serious colorectal-related complications, and the brief summary centers on leakage during or after surgery. Yet the record does not report the endpoint count or an analysis of that outcome. Without those results, the intended question cannot be answered from the posted data.
The single-group structure is also important. A study can describe outcomes among participants who received an intervention, but without a suitable comparison it cannot separate the intervention’s contribution from other factors that influence outcomes. This distinction is central to interpreting device studies in surgical settings, where the registry record does not establish a randomized reference group.
The safety information illustrates why outcome definitions and denominators matter. The registry provides counts and serious-event terms, but does not explain how those categories relate to the primary endpoint. Treating safety listings as if they were the primary analysis would blur distinct measures and could produce an unsupported interpretation.
General statistical context: Statistical conclusions depend not only on the design but also on transparent reporting of estimates, uncertainty, missing data, and analysis choices. A completed status and an enrollment figure do not show the magnitude or precision of an outcome. When those result details are absent, readers should keep conclusions bounded to what the registry actually reports.
The record is useful for identifying the intervention, the single-group design, the intended endpoint and the presence of adverse-event reporting. Its limits are equally important: no primary result, no inferential analysis and no comparative estimate are reported. That boundary helps prevent descriptive information from being mistaken for evidence of treatment effect.
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.
The main limitation specific to interpreting this study is the absence of a reported primary endpoint result. The registry identifies the endpoint as the number of participants with leak, stricture and hemorrhage at discharge and 1 Month post surgery, but does not report the number meeting that definition. No effect estimate, confidence interval, or primary-outcome test is reported either.
The single-group design limits comparative interpretation. The record lists one reinforcement arm and no randomized comparison. An observed outcome frequency in that arm, even if reported, would not by itself establish what the frequency would have been without the intervention or under another approach.
Further details needed to assess the endpoint are not reported in the registry record. These include operational definitions of the event types, how events were counted if a participant experienced more than one type, participant flow through follow-up, and the handling of missing observations. The analysis population and statistical methods are also not reported.
The safety entries have their own limits. The record lists serious and other adverse-event counts, along with serious-event terms and percentages, but does not provide a detailed account of timing, severity, event-specific denominators, or overlap between affected categories. Deaths are not reported in the registry record. The safety listings cannot be assumed to match the primary endpoint definition.
Finally, the registry does not report the original sample-size justification, interim analyses, or a statistical analysis plan. The stated sample-size assumptions concern a planning illustration rather than the trial’s own design. These reporting gaps restrict assessment of the study’s precision and analytic choices; they do not establish what occurred outside the information recorded.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Peri-Strips Dry (PSD) Veritas Collagen Matrix Staple Line Reinforcement for Colorectal Surgery — NCT00559013.
- Registry record last updated 2017-05-10; status last verified 2017-04.
- Results first posted 2012-05-24.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
19. Record Summary
The registry record describes a completed, single-group device study of PSD Veritas Collagen Matrix staple-line reinforcement for colorectal surgery. Baxter Healthcare Corporation is listed as sponsor, enrollment is 38, and phase is NA. The recorded study dates are 2007-03 for start and 2008-12 for primary completion.
The primary endpoint is the number of participants with major colorectal-related adverse events—leak, stricture and hemorrhage—at discharge and 1 Month post surgery. The record lists one outcome measure and zero analyses, but does not report a primary endpoint result or statistical analysis. Safety entries list 3 affected among 38 at risk for serious adverse events and 2 affected among 38 at risk for other adverse events. Serious-event terms include Anastomotic Buttress Leak at 7.9% and Bleeding at 2.6%.
Because the design is single group, the record does not provide a randomized or like-for-like control comparison. The posted information supports description of the design and listed safety entries, but not a comparative estimate of intervention effect.