Bactiseal Catheter Safety Registry in China: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Bactiseal Catheter Safety Registry in China (NCT04496414), a registered phase not stated study. The primary outcome is 50 Participants With Non-infection Within One Year.

2. Clinical Question

The registry concerns people with hydrocephalus who were implanted with a Bactiseal Catheter. Its stated purpose was to continue evaluating safety information, including adverse events occurring within one year after implantation. The primary endpoint is titled as the number of participants with non-infection within one year; the posted record does not give an observed count for that endpoint.

3. Trial Design

This is a multicenter, retrospective registry study of the safety of Bactiseal Catheter. The registry lists the study as completed and gives an enrollment of 50. It identifies hydrocephalus as the condition and Integra LifeSciences Corporation as the sponsor. The study title locates the registry in China.

The record lists a start date of 2020-09-01 and a primary completion date of 2020-11-30. Its stated safety objective concerns adverse events within one year after catheter implantation. The primary endpoint also specifies a one-year timeframe. These registry dates describe the study record; further details about when individual participants were implanted or followed are not reported in the registry record.

The intervention listed is the Bactiseal Catheter, with a single Bactiseal Catheter Arm in the posted adverse-event information. No randomized comparison is described, and allocation is not stated. The listed arm therefore should not be read as one side of a controlled comparison. The record does not report a separate control group or a comparison of outcomes between groups.

The registry lists two outcome measures and no analyses. It provides adverse-event counts for the listed group, but the primary endpoint's observed count is not reported in the registry record. Further details about participant eligibility, recruitment, data sources, follow-up completeness, and the procedures used to identify and classify events are not reported in the registry record. Those omissions limit how fully the registry design and the completeness of its safety observations can be assessed.

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: Screened 62 patients, 50 of them were enrolled, including 7 adult patients and 43 minors (subject age below 18). 12 patients were screening failures for not meeting inclusion/exclusion criteria and without post operation follow up.

Overall Study

Analysis population for the primary outcome, as defined in the registry: 50 participants implanted Bactiseal Catheter for 1 year

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: 50 enrolled subjects were included into PPS

6. Primary Endpoint

The registry lists the primary outcome as 50 Participants With Non-infection Within One Year, measured over 1 year.

The primary endpoint is titled “50 Participants With Non-infection Within One Year” and is described as a count of participants with non-infection within one year. Its unit is participants, and its timeframe is 1 year. A count endpoint records how many people meet a stated event definition during a specified period; it is not itself a rate unless it is related to an appropriate denominator and time-at-risk information.

In general, a non-infection endpoint may be used to describe an aspect of safety that is distinct from infection events. The registry does not report the operational definition of non-infection, how events were adjudicated, or whether the endpoint means at least one qualifying event per participant. These details matter because an endpoint definition determines which events are counted and how participants with multiple events are represented.

The posted record does not state the observed count for this primary endpoint, nor does it report an estimate of uncertainty or an analysis. Consequently, the endpoint label and timeframe identify what was intended to be measured, but they do not provide the numerical result. The broader safety purpose refers to all adverse events within one year; the relationship between that purpose and the specifically titled non-infection endpoint is not further explained in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a binary-type participant count: participants with non-infection within one year. In general, a binary outcome classifies each participant according to whether a defined event occurred during a specified period. A count is the number classified as having the event; interpretation usually also depends on the denominator, the event definition, and how missing or incomplete follow-up is handled. The posted record does not report the observed primary count or those analysis details.

What does a participant count represent?

A participant count differs from an event count. If an endpoint counts participants, a person who has repeated instances of the event may still contribute only once, depending on the prespecified definition. If it counts events, repeated instances may contribute multiple times. The endpoint is described in participant units, but the registry does not state whether the non-infection definition is based on any qualifying event, nor how repeated events were handled. The serious and other adverse-event summaries are also expressed as affected-participant counts, while the serious-event terms are listed separately as percentages.

In general, a proportion pairs an event count with the number of participants assessed for that outcome. The group-level adverse-event information includes counts at risk and counts affected. That information supports describing the posted counts within the listed group, but it does not provide a control-group estimate. The primary endpoint's observed count is absent, so a primary-endpoint proportion cannot be interpreted from the registry record. No new proportions or effect measures are calculated in this explanation.

Why does the study design matter?

This is a retrospective registry study, and the record does not describe a randomized comparison. Allocation is not stated. In general, a randomized comparison can support a structured estimate of a difference between assigned groups, subject to the trial's conduct and analysis. A single listed group instead provides observations among participants who received the device, without a concurrent control in the posted results. Other factors affecting safety cannot be separated from the device using these descriptive data alone.

A group label does not establish that a control arm exists. The registry lists only the Bactiseal Catheter Arm in its adverse-event information, and the record explicitly cautions that the arms are not a like-for-like control comparison. Therefore, no between-group contrast should be inferred from that label. The registry does not report a comparative estimate or an adjustment for other factors.

What can uncertainty measures add?

In general, a confidence interval communicates the uncertainty around an estimated quantity under a specified statistical model. A narrow interval indicates greater precision than a wide interval, while neither interval width nor inclusion of a particular value alone resolves issues of bias or data quality. The registry record does not report confidence intervals for the primary endpoint or the adverse-event summaries. It also does not report an inferential analysis. The counts should not be presented as if they were precise estimates of risks in a broader population.

For a binary outcome, statistical methods may estimate a proportion or compare proportions when the study design supplies appropriate groups and a prespecified analysis. Those methods require clarity about the outcome definition, analysis population, and treatment of missing observations. Here, the primary result is not reported and there is no reported control group or analysis. As a result, a recalculated comparison is not available from the registry information.

How should the planning illustration be understood?

The planning assumptions describe a sample-size illustration, not the registry's own study design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect expressed as a stated fraction of the observed effect. For non-time-to-event outcomes, the convention is participants per arm for 80% power or 90% power; time-to-event planning uses a total number of events. These are planning conventions, not observed findings, and any sample-size values in such an illustration should not be called observed power.

In general, a sample-size calculation asks how much information a future study would need under stated assumptions. Its result depends on assumptions about the effect to detect, variability or event frequency, allocation, significance level, and analysis method. It does not demonstrate that the current study had a particular probability of detecting an effect. The registry does not report a sample-size justification for this retrospective registry, and the planning illustration should not be mistaken for such a justification.

The record reports no analyses. It does not state a statistical model, an estimation method, a missing-data method, a multiplicity adjustment, or whether any interim analyses were planned or conducted. Those details are not reported in the registry record. General statistical methods can explain what such choices mean, but they cannot replace a missing analysis plan or produce an unreported primary result.

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("Bactiseal Catheter Arm")
n      <- c(50)
events <- c(1)
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  Bactiseal Catheter Arm  50  1  2.0  0.1  10.6  0.4  10.5  0.5  10.4

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, but does not report an analysis for either one. It identifies a primary endpoint and a secondary outcome concerning the type and incidence of adverse events among 50 subjects within one year. The record does not explain how the primary and secondary outcomes were prioritized in analysis, whether multiple statistical tests were planned, or whether any multiplicity adjustment was used. These details are not reported in the registry record.

In general, multiplicity arises when several outcomes, comparisons, or statistical tests are evaluated. Without a prespecified approach, repeated testing can make isolated findings harder to interpret. That general concern does not establish that the registry conducted multiple tests: the posted record lists no analyses, so there are no reported test results to assess for multiplicity.

Information about missing data and analysis populations is also limited. The registry lists an enrollment of 50 and describes the primary endpoint population as 50 participants implanted with the catheter for 1 year. It does not report whether every enrolled participant contributed complete one-year follow-up, how missing observations were treated, whether participants were excluded from an analysis, or which analysis population was used. The registry's endpoint description does not establish that all participants had complete outcome data.

In general, missing follow-up can affect both the denominator and the interpretation of safety counts, especially if the probability of missingness is related to outcome status. The record does not report reasons for missingness or a method for assessing its impact. Accordingly, the observed adverse-event summaries can be described as posted, but the completeness of ascertainment and the handling of missing data cannot be evaluated from the registry record.

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 4% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cerebral hemorrhage (4.0%), subdural hematoma (4.0%), intracranial infection (2.0%), shunt device disorder (2.0%), shunt device occlusion (2.0%).

The listed Bactiseal Catheter Arm has 50 participants at risk for serious adverse events, with 13 affected. For other adverse events, the listed figures are 50 at risk and 30 affected. The record separately lists 1 death. These figures describe the registry's group-level safety reporting; they do not establish causation or compare the device with an untreated or alternative-device group.

The serious-event terms are reported as percentages: cerebral hemorrhage, 4.0%; subdural hematoma, 4.0%; intracranial infection, 2.0%; shunt device disorder, 2.0%; shunt device occlusion, 2.0%; and shunt blockage, 2.0%. The registry record does not provide event narratives, timing, severity grading beyond the serious-event classification, or information about whether one participant could have multiple listed terms. The percentages should therefore be read as the registry reports them, not reinterpreted as mutually exclusive categories.

The serious and other affected-participant counts may overlap, and the record does not say otherwise. They should not be summed to infer a total. Nor do the group-level summaries show whether all events were observed throughout the stated one-year period. The registry describes a one-year safety objective, but participant-level follow-up completeness and event ascertainment procedures are not reported in the registry record.

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

The registry contributes descriptive safety information for participants implanted with Bactiseal Catheter in a study focused on hydrocephalus. It records serious and other adverse-event counts for its listed group and names several serious-event terms with reported percentages. The study is listed as completed, and its stated safety objective concerns events within one year after implantation. These details describe what the registry set out to evaluate and what adverse-event information it posts.

The posted information does not include the observed result for the primary endpoint, participants with non-infection within one year. It also does not include an analysis or a control-group comparison. As a result, it cannot show whether the frequency of events was higher or lower than it would have been under another device or care approach. A group-level safety count cannot isolate the contribution of the catheter from other explanations.

In general, a registry can be useful for organizing safety observations, particularly when the purpose is descriptive. Interpretation depends on who entered the registry, how events were identified, how complete follow-up was, and how outcomes were defined. The registry record does not report enough detail on those points to assess the possibility of incomplete event capture or selection effects. The results also do not establish how well the observations apply beyond the people represented in the record.

The posted counts do not establish that the device caused a reported event, and absence of a reported primary endpoint value cannot be interpreted as an absence of non-infection events. The record does not report the primary numerical result or a statistical estimate of its precision. Therefore, conclusions should remain limited to the descriptive safety information actually recorded and the study purpose and timeframe stated in the registry.

14. Why This Trial Matters Statistically

Safety registries and clinical trials answer different statistical questions depending on their design. This record is a retrospective, multicenter registry focused on Bactiseal Catheter safety. It gives a setting in which adverse events were recorded and a one-year safety objective, while the posted results identify serious and other affected-participant counts. Those observations can be important for describing what was recorded among participants in the listed group.

The statistical distinction between description and comparison is central. The record does not describe a randomized comparison, does not state allocation, and does not provide a control group in the posted adverse-event information. Without a comparator and a reported analysis, the counts cannot estimate a difference attributable to the catheter. The group label does not change this limitation.

The primary endpoint also illustrates why outcome definitions and complete reporting matter. It is expressed as a participant count within a one-year timeframe, but its observed value is not reported in the registry record. The record does not explain the operational definition of non-infection, how missing follow-up was handled, or which participants contributed to the analysis. Those elements are necessary to interpret the endpoint fully and assess its precision.

More broadly, the registry shows why safety summaries should be read alongside design, endpoint, and analysis details. Counts can convey the occurrence of recorded events, while an analysis plan and suitable comparison are needed for inferential claims. Here, the study's descriptive safety purpose is clear, but several details needed to assess completeness, uncertainty, and comparative meaning are not reported in the registry record.

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 limitations specific to this record constrain interpretation. The study is described as retrospective and has a single listed Bactiseal Catheter Arm in the posted adverse-event information. No randomized comparison is described, allocation is not stated, and no like-for-like control comparison is available. The serious and other adverse-event summaries therefore cannot establish a relative safety difference.

The primary endpoint is identified, but its observed count is not reported in the registry record. There are no reported analyses, confidence intervals, or inferential test results. The registry lists an enrollment of 50 and describes the endpoint population as 50 participants, but it does not say whether all had complete one-year follow-up or how missing data were handled. The record also does not report the endpoint's operational definition or the procedures used to identify and classify events.

The adverse-event summaries are limited to group-level counts and selected serious-event terms. The record does not provide event-level narratives, timing, or a statement about overlap among categories. Consequently, the counts cannot be combined to infer an overall number of affected participants, and the percentages for terms should not be treated as mutually exclusive.

Additional design information, including eligibility criteria, data sources, and details of participant selection, is not reported in the registry record. The record does not state a statistical analysis plan, a sample-size justification for the registry, or how multiple outcomes were handled analytically. These omissions prevent a fuller assessment of potential selection, ascertainment, and analysis limitations. The results should accordingly be read as registry descriptions, not as a controlled estimate of device effects.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Bactiseal Catheter Safety Registry in China — NCT04496414.
• Registry record last updated 2023-03-28; status last verified 2023-02.
• Results first posted 2021-12-21.
• 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 registry record describes a completed, multicenter, retrospective safety study of Bactiseal Catheter in China. Hydrocephalus is the listed condition, Integra LifeSciences Corporation is the sponsor, and the enrollment is 50. The recorded start date is 2020-09-01, and the primary completion date is 2020-11-30.

The stated safety objective concerns adverse events within one year after implantation. The primary endpoint is a count of participants with non-infection within one year, but its observed count is not reported in the registry record. The adverse-event information lists 13 participants affected by serious events and 30 affected by other events in the Bactiseal Catheter Arm, with 1 death recorded. Several serious-event terms and percentages are also listed.

The registry reports no analyses and does not describe a randomized comparison or a control group in the posted safety information. Details about endpoint definitions, missing data, and analysis populations are not reported in the registry record. The available figures are descriptive and do not provide a comparative effect estimate.