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 Product Evaluation for the Effectiveness of the ClearGuard™ HD End Cap (NCT02604264), a randomized na study. The primary outcome is Positive Blood Cultures (PBCs) Per 1,000 Central Venous Catheter (CVC)-Days.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02604264 |
| Phase | NA |
| Condition | End Stage Renal Disease (ESRD) |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 2912 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Pursuit Vascular, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned hemodialysis patients with end-stage renal disease who used a central venous catheter. The primary outcome description refers to subjects who participated and were not otherwise censored when catheter-days were counted. Further eligibility details and participant characteristics are not reported in the registry record.
Intervention
The intervention was the ClearGuard HD end cap, described in the record as a device. The study summary frames the question around positive blood cultures among hemodialysis central venous catheter patients using this end cap. Details of device use beyond the intervention name are not reported in the registry record.
Comparator
The comparator was the standard hemodialysis end cap, identified as the control. The brief summary describes the comparison as ClearGuard HD end caps versus conventional end caps. Further information about the standard cap or differences in care between groups is not reported in the registry record.
Primary question
The primary question was whether the two groups differed in the rate of positive blood cultures, expressed per 1,000 central venous catheter-days, over a timeframe of up to 12 months. Positive blood cultures were counted under a stated event rule, and catheter-days represented time at risk. The registry reports rates of 0.26 for the ClearGuard group and 0.59 for the control group. It does not report a statistical test or an estimate of uncertainty for the comparison.
3. Trial Design
The registry describes a randomized, parallel-group study with no masking. Its status is completed, and the recorded enrollment is 2912. The study start is listed as 2014-12, and primary completion as 2015-11. The condition listed is end-stage renal disease. The phase is recorded as not applicable.
The intervention was the ClearGuard HD end cap, and the control was the standard hemodialysis end cap. The registry identifies the study as a device evaluation and describes its objective as assessing positive blood cultures in hemodialysis patients with central venous catheters. Randomization means assignment to groups was intended to be determined by chance, but the method used to generate or conceal assignments is not reported in the registry record.
The primary outcome was a rate rather than a simple proportion of participants with an event: positive blood cultures per 1,000 central venous catheter-days. Its timeframe was up to 12 months. The outcome description defines how events and at-risk time were counted, including an event rule for repeated positive cultures. However, the registry record does not give additional details about visit schedules, follow-up procedures, adherence, or the handling of treatment changes.
The posted outcome lists 1245 in the treatment group and 1225 in the control group. These are the arm counts attached to the outcome results; the record does not explain how they relate to the overall enrollment or provide a detailed participant flow. It also does not report baseline characteristics or an analysis plan. Randomization and parallel assignment describe the intended comparison, but they do not by themselves establish that all other aspects of trial conduct or analysis were comparable.
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.
Run-In
| Stage | Treatment | Control |
|---|---|---|
| STARTED | 618 | 611 |
| COMPLETED | 618 | 611 |
| NOT COMPLETED | 0 | 0 |
Intervention
| Stage | Treatment | Control |
|---|---|---|
| STARTED | 1445 | 1467 |
| COMPLETED | 1245 | 1225 |
| NOT COMPLETED | 200 | 242 |
Reasons for not completing this period:
| Reason | Treatment | Control |
|---|---|---|
| Didn't use CVC for at least 21 days | 200 | 242 |
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: This is the intervention population data. The baseline data came from the 1 month run-in period prior to the start of the intervention period and is referred to as the run-in rather than baseline period. The run-in data was used to determine pre-study demographics and PBC rate.
| Characteristic | Unit | Treatment | Control | Total |
|---|---|---|---|---|
| Participants analysed | 1245 | 1225 | 2470 | |
| Age, Continuous | years | 61.5 (SD 15.1) | 60.6 (SD 15.1) | 61.1 (SD 15.1) |
| Sex: Female, Male: Female | Participants | 591 | 559 | 1150 |
| Sex: Female, Male: Male | Participants | 654 | 666 | 1320 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 | 24 | 25 |
| Race (NIH/OMB): Asian | Participants | 13 | 12 | 25 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 3 | 4 | 7 |
| Race (NIH/OMB): Black or African American | Participants | 566 | 495 | 1061 |
| Race (NIH/OMB): White | Participants | 609 | 631 | 1240 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 53 | 59 | 112 |
| Region of Enrollment: United States | Participants | 1245 | 1225 | 2470 |
6. Primary Endpoint
The registry lists the primary outcome as Positive Blood Cultures (PBCs) Per 1,000 Central Venous Catheter (CVC)-Days, measured over Up to 12 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | PBCs per 1,000 CVC-days |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was positive blood cultures per 1,000 central venous catheter-days, with results reported for a timeframe of up to 12 months. A rate places the number of counted events in relation to the amount of time participants were at risk while using a catheter. This can be useful when time at risk differs among participants, because the outcome reflects both event counts and accumulated exposure time rather than simply the share of participants who experienced an event.
The registry says the rate was calculated by dividing the cumulative number of positive blood cultures by cumulative at-risk time. Catheter-days were calculated by summing the days each participant was at risk of accruing a positive blood culture. The population for this analysis included subjects who participated and were not otherwise censored, as described in the outcome definition.
The event rule followed the stated National Healthcare Safety Network outpatient hemodialysis patient rule: a positive blood culture counted as a new event only if it occurred at least 21 days after a previously reported event in the same patient. Eligible cultures were drawn as an outpatient or within one calendar day after a hospital admission. Additional same-type events after a positive culture were counted beginning 21 days after the initial event, and catheter-days were counted during that period.
The registry reports the rates but not the underlying cumulative event counts or cumulative catheter-days. It also does not report a dispersion measure or confidence interval for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary outcome rate is 0.26 positive blood cultures per 1,000 central venous catheter-days in the ClearGuard group and 0.59 per 1,000 central venous catheter-days in the control group. Descriptively, the recorded rate is lower in the ClearGuard group. These values alone do not establish whether the difference is compatible with chance variation or how precisely the underlying rates have been estimated.
The registry does not report a confidence interval, p-value, or other inferential comparison for this endpoint. It also lists no analyses. As a result, the posted results do not provide a sponsor-reported test of the contrast or a measure of its uncertainty. The registry record does not establish that the observed difference is statistically significant, nor does it establish that the groups have equivalent rates.
Rates are based on events in relation to time at risk, not simply on the number of participants. The outcome definition describes how catheter-days were accumulated and which positive blood cultures counted as new events. The underlying event totals and time totals are not reported, so the posted rates cannot be independently reconstructed from those quantities. The arm counts shown with the outcome are 1245 for treatment and 1225 for control; they should not be treated as the denominators of the rates, which are expressed per catheter-day exposure.
The study was randomized, but the record does not describe allocation concealment, baseline balance, adherence, or the analysis method. Randomization supports a planned comparison between groups, yet interpretation also depends on how the outcome was analyzed and how missing observations, censoring, and departures from assigned treatment were handled. Beyond the censoring language in the endpoint definition, those details are not reported in the registry record.
The outcome is a count rate, and rates can be estimated with different statistical approaches. Some methods make assumptions about the relationship between the event count and the exposure time; other approaches can allow extra variability, sometimes called over-dispersion. These are general statistical considerations, not claims about the method used in this study. The registry does not state which model, if any, was used to compare the arms.
The rates are therefore best read as the posted descriptive outcome values under the registry's event-counting rule. They do not, on their own, give a causal estimate with quantified precision. The record also does not report secondary outcomes, so the primary rate is the only posted clinical outcome available for this comparison.
9. Statistical Methods Explained
The primary outcome is a rate constructed from a count and an exposure-time denominator. The numerator is the cumulative count of positive blood culture events under the registry's event rule. The denominator is cumulative time at risk, measured in central venous catheter-days. The resulting rate is expressed per 1,000 catheter-days. This type of endpoint differs from a participant-level proportion: a proportion asks whether a person had an event, whereas a rate also incorporates the amount of time at risk.
How does the event rule affect counting?
Repeated positive cultures cannot automatically be treated as separate events without a rule. The registry uses the National Healthcare Safety Network outpatient hemodialysis patient rule: a positive blood culture is considered a new event only if it occurs 21 days or more after a previously reported positive blood culture in the same patient. The description also specifies cultures drawn as an outpatient or within one calendar day after hospital admission. Additional same-type events after a positive culture begin to count 21 days after the initial event. Applying such a rule aims to distinguish a new event from a continuation or repetition close in time; it is part of the endpoint definition, not an inferential statistical test.
What does exposure time contribute?
Participants may contribute different amounts of time at risk. Summing at-risk catheter-days allows the rate to reflect that variation in exposure. The registry says catheter-days were summed for each patient while that patient was at risk of accruing a positive blood culture, and that the analysis included participants who were not otherwise censored. Censoring means that a participant's observed contribution to follow-up ends under a specified rule. The record provides this general endpoint language but does not detail the reasons for censoring or the analysis procedures used to account for it.
How should the two rates be compared?
The treatment rate is 0.26 per 1,000 catheter-days, and the control rate is 0.59 per 1,000 catheter-days. A formal comparison would ordinarily need to account for the count process and its exposure time, and to quantify uncertainty around the estimated contrast. General approaches for rate data can include count models with an exposure-time offset or other methods suited to event rates. This is general statistical context only; the registry record does not report that any particular model was used. It gives neither a model-based estimate nor a confidence interval or p-value.
For count outcomes, one possible concern is over-dispersion: the observed variation may be greater than assumed by a simple count model. If that occurs, standard errors from a model that does not allow for the extra variation can be too small, making uncertainty appear less than it is. Other issues can arise if events are clustered within participants or if participants have different underlying event risks. These are general methodological considerations. There is no information in the registry record to determine whether over-dispersion, within-participant correlation, or other model assumptions were assessed.
What can be inferred from the posted precision?
No confidence interval or other uncertainty measure is posted for the primary rates. A confidence interval is a statistical range intended to express the uncertainty associated with an estimate under a specified method and assumptions. Without one, readers cannot gauge the precision of either rate or the estimated difference using the registry results. The record also lists zero analyses, so a reported inferential test is not available. The rates can be described as the reported values, but a statistical conclusion about the comparison cannot be drawn from them alone.
What is the role of sample-size planning?
The registry's stated planning illustration assumptions use the observed effect, two-sided significance level 0.05, equal allocation between arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event illustrations, the stated quantity is the total number of events, while other illustrations express participants per arm. Such calculations are planning illustrations, not observed power and not evidence that the original study was designed around those assumptions. The original sample-size justification and planned statistical design are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure and no secondary outcomes. It also lists zero analyses. A multiplicity strategy, such as a plan for interpreting several outcome tests together, is not reported in the registry record. With no posted analyses or additional outcome results, the record does not allow assessment of how multiple comparisons may have been handled.
The primary endpoint description says the analysis included subjects who participated and were not otherwise censored, and it explains how catheter-days at risk were counted. That description is not a full account of missing-data methods or of the analysis population. The registry does not report how missing culture information, incomplete follow-up, withdrawals, or other unavailable observations were handled, nor does it describe any sensitivity analyses.
The registry records enrollment of 2912 and reports outcome arm counts of 1245 and 1225. It does not provide a participant flow or reconcile these figures. The record does not state whether the outcome analysis followed an intention-to-treat approach, a per-protocol approach, or another population definition. It also does not describe treatment switching or adherence in the analysis.
These omissions limit interpretation of the reported rates. The censoring and event-counting rules clarify aspects of the endpoint, but they do not replace a full account of analysis populations, missingness, and prespecified methods.
11. 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 |
|---|---|---|---|
| Treatment | 0 | 1245 | 0.0% |
| Control | 0 | 1225 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment | 134 of 1245 |
| Control | 127 of 1225 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Treatment | 0 of 1245 |
| Control | 0 of 1225 |
The registry reports zero serious adverse events among 1245 participants at risk in the treatment group and zero among 1225 at risk in the control group. It also reports zero other adverse events in each group. These are the posted counts; the record does not provide event descriptions for these categories.
Deaths are listed separately, with 134 in the treatment group and 127 in the control group. The registry does not state whether these deaths were considered related to the device, how they were classified in relation to adverse-event reporting, or when they occurred. The counts should not be interpreted as evidence of causation or as a comparison adjusted for follow-up time or participant characteristics.
Zero reported serious or other adverse events does not establish that no events occurred outside the registry's reporting definitions or observation procedures. The record does not describe safety definitions, collection methods, follow-up duration for safety, or whether the categories capture all events. These figures are best read as the adverse-event counts posted in the registry, with the available details and attribution limitations kept in view.
12. What the Result Does, and Does Not, Mean
The registry records a randomized comparison of ClearGuard HD end caps with standard hemodialysis end caps and reports positive blood culture rates of 0.26 and 0.59 per 1,000 central venous catheter-days, respectively. These values describe the outcome under the registry's event definition and exposure-time calculation. The recorded rate is numerically lower in the ClearGuard group, but the posted results do not quantify uncertainty around that contrast.
The record does not report a statistical test, confidence interval, or analysis model for the primary outcome. Therefore, the rates do not show how compatible the observed comparison is with chance variation or how much precision the estimates have. They also do not establish equivalence between the groups. A descriptive difference and a statistically supported treatment effect are not interchangeable conclusions.
The endpoint is specific to positive blood culture events counted under a stated timing rule among hemodialysis patients using central venous catheters. It is not a report of every possible infection outcome or of outcomes beyond the listed measure. The timeframe is up to 12 months, and the record does not provide additional detail about the distribution of follow-up or the underlying event and catheter-day totals.
The study's randomized design is relevant to the intended comparison, but the available registry information does not describe allocation procedures, baseline characteristics, adherence, missing-data handling, or a complete analysis population. Those details matter when judging whether the observed group rates can be interpreted as an unbiased estimate of a treatment contrast.
Accordingly, the result supports a limited statistical description: the registry posted different observed rate values for the two groups. It does not, on its own, establish a causal effect, the precision of a causal estimate, or the broader clinical implications of the comparison.
13. Why This Trial Matters Statistically
This trial illustrates why a rate endpoint can be useful when follow-up time varies. Counting events alone does not account for how long participants were at risk. Relating positive blood culture events to catheter-days gives the outcome an exposure-time denominator, making the measure interpretable as events per unit of catheter use. The registry's event rule also shows that a clinical count endpoint depends on explicit decisions about when repeated observations count as new events.
It also demonstrates the difference between a reported outcome value and a complete statistical comparison. The registry provides the two arm-specific rates, but not an inferential estimate, uncertainty interval, or analysis method. Without those elements, readers can describe the observed rates but cannot judge the statistical precision of their contrast from the posted results.
Finally, the record highlights the importance of transparent reporting beyond a headline endpoint. Censoring language and the event definition clarify part of the outcome construction, while details about missing data, analysis populations, baseline characteristics, and the statistical plan are not reported. Those elements help readers understand how a rate was produced and how strongly it supports conclusions about differences between groups.
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 registry record has limited statistical detail for this trial. It reports the arm-specific primary outcome rates but no confidence intervals, p-values, analysis model, or other inferential results. The cumulative event counts and cumulative catheter-days used to form the rates are not reported, so the outcome calculation cannot be independently reproduced from the posted information.
The description specifies a 21-day event-counting rule and a general approach to accumulating at-risk catheter-days, but it does not give a complete account of censoring decisions or missing observations. The analysis population is not named as intention-to-treat, per-protocol, or another defined set. A participant flow and an explanation of the relationship between recorded enrollment and outcome arm counts are not reported in the registry record.
Other details that could inform interpretation are also unavailable, including baseline characteristics, allocation concealment, adherence, and a full statistical plan. The record does not report whether the analysis addressed extra variation or repeated events within participants. It lists no secondary outcomes and no analyses, so the primary rate is the only posted clinical outcome result available for statistical interpretation.
The safety counts are similarly limited by absent definitions and attribution details. The record reports adverse-event and death counts but does not describe collection procedures, timing, or whether events were considered related to the intervention. These gaps do not change the posted values, but they restrict the conclusions that can be drawn from them.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Product Evaluation for the Effectiveness of the ClearGuard™ HD End Cap — NCT02604264.
- Registry record last updated 2018-09-11; status last verified 2018-06.
- Results first posted 2017-05-01.
- 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.
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18. Record Summary
NCT02604264 is a completed randomized, unmasked, parallel-group device study sponsored by Pursuit Vascular, Inc. The registry records enrollment of 2912, a start date of 2014-12, and primary completion in 2015-11. The study compared the ClearGuard HD end cap with the standard hemodialysis end cap in hemodialysis patients with end-stage renal disease.
The primary outcome was positive blood cultures per 1,000 central venous catheter-days over a timeframe of up to 12 months. The posted rates are 0.26 for treatment and 0.59 for control. The record lists no analyses and reports no confidence interval or statistical test for this comparison. It lists zero serious and zero other adverse events in each group, alongside death counts of 134 in treatment and 127 in control.
Important details about the statistical plan, missing data, and analysis population are not reported in the registry record.