DirectVision for Urinary Catheterization: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for DirectVision for Urinary Catheterization (NCT03066999), a randomized na study. The primary outcome is Set up Time/Total Procedure Time to Place Catheter Via DirectVision/Cystoscope.

2. Clinical Question

The registry record describes a study of catheter placement using DirectVision or cystoscopy. Its stated aim is to assess the effectiveness and ease of use of the DirectVision system. The primary measure concerns the time needed to set up and complete catheter placement, rather than a reported measure of success or patient benefit. The registry record does not report results for that measure, so the comparative question remains unanswered by the posted results.

3. Trial Design

NCT03066999 is recorded as a randomized, parallel study with no masking. Its official title describes a prospective study at a single center. The record lists DirectVision and cystoscopy as the two procedures being compared, with catheter placement assigned to the relevant method. The registry lists the study phase as not applicable.

Enrollment is recorded as 5. The study start date is 2017-03-07, and the primary completion date is 2017-10-01. Its status is terminated. The reason for termination and the timing of that decision are not reported in the registry record. The sponsor is The Pur Clinic.

Random allocation is intended to assign participants to comparison groups by chance. In general, randomization can help reduce systematic differences between groups, although it cannot guarantee balance, especially in a small study. With enrollment recorded as 5, any observed group differences could reflect chance imbalance as well as differences associated with the procedures. The registry does not report the randomization method, allocation concealment, or whether the intended allocation was achieved.

The absence of masking is important for interpreting a procedural comparison. Clinicians performing catheter placement would know which method they were using; the record does not say whether outcome assessment was masked. Knowledge of the assigned method can affect procedural conduct or measurement, particularly for a time-based endpoint. The registry record does not describe who recorded procedure times or how timing was standardized.

The record lists 7 outcome measures, but it reports no analyses. The primary outcome is described as set-up time and total procedure time, while a secondary outcome concerns the cost of using cystoscopy versus DirectVision. Details for the remaining measures are not available in the registry record. It does not provide an analysis plan or results that would allow the randomized comparison to be evaluated.

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: No enrolled patients were excluded from the study before assignment to groups

Overall Study

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Set up Time/Total Procedure Time to Place Catheter Via DirectVision/Cystoscope, measured over prep and duration of procedure, up to 1 hour.

The primary endpoint is titled “Set up Time/Total Procedure Time to Place Catheter Via DirectVision/Cystoscope.” It measures the duration, in minutes, to set up and complete catheter placement using either method. Its stated timeframe is preparation and procedure duration, up to 1 hour. The registry description says duration was observed and calculated in minutes.

Procedure time is a direct operational measure: it describes how long the procedure took, rather than whether placement was successful, whether injury occurred, or how a patient felt afterward. Such a measure can be useful when a study aims to assess procedure duration or ease of use. However, time alone cannot establish effectiveness. Interpretation would depend on the exact start and end points, consistent timing procedures, and how incomplete or interrupted procedures were handled. Those details are not reported in the registry record.

The endpoint specifies a mean and full-range dispersion. In general, a mean describes the average of the recorded times, while the full range describes the lowest and highest recorded values. A range can make the spread of observations visible, but with few observations it may be strongly influenced by an unusually short or long procedure. No mean times, ranges, or arm-specific endpoint results are reported in the registry record. Therefore, the posted information does not show whether either method took less time or how precisely any difference was estimated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies randomization, a parallel-group model, and no masking. These labels describe broad design features, not the full statistical methods. The specific randomization procedure, planned analyses, handling of missing observations, and criteria for including participants in each analysis are not reported in the registry record. Without those details and without reported outcome data, the primary comparison cannot be reconstructed.

What does randomization contribute?

In general, randomization assigns participants to interventions through a chance process. It is used to limit systematic differences in known and unknown characteristics between groups. It does not ensure that the groups will be alike in every respect, and chance imbalance can be important when enrollment is small. The registry records enrollment as 5, but does not provide a baseline-characteristics table or explain how allocation was generated or concealed. The word randomized therefore describes the design, but does not by itself show that all possible sources of bias were addressed.

The parallel model means the two methods are compared across groups rather than by requiring each participant to receive both methods in sequence. The record does not describe the timing of allocation relative to enrollment, whether participants crossed over, or whether any assigned procedure was not performed. Those implementation details are not reported in the registry record.

How should a mean and full range be read?

The endpoint specifies a mean and full range. In general, the mean summarizes the central level of measurements by averaging them. The full range gives the span from the smallest to the largest observed value. These summaries answer different questions: the mean describes an average duration, while the range conveys the spread of recorded durations. A range can be sensitive to extreme observations, and neither summary alone shows the complete distribution.

Procedure times may vary for reasons beyond the assigned method, including case complexity and procedural circumstances. That is a general consideration, not a reported finding about this study. With sparse data, an average may be unstable and the range may depend heavily on individual observations. To judge the primary outcome, readers would need arm-specific values and a clear account of how timing began and ended. The registry does not report those values or operational definitions beyond the stated set-up and total duration.

What does the sample-size illustration represent?

The registry describes a planning illustration computed from the observed effect. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. The record does not include the calculated sample-size values or the observed effect used for the illustration. Accordingly, no planning number can be interpreted from the posted information.

In general, a sample-size calculation estimates how many participants a future study would need under specified assumptions to have a chosen chance of detecting an effect of interest at a chosen significance level. A calculation based on an observed effect can be particularly uncertain when the original study is small, because the estimate itself may be imprecise. The registry’s illustration is a planning exercise, not evidence that the terminated study had adequate power. It is not observed power, and it cannot tell readers whether the study detected an effect.

What would uncertainty measures add?

In general, a confidence interval expresses the uncertainty around an estimated effect under the analysis assumptions. It indicates which effect sizes remain compatible with the observed data and method, rather than reporting only a point estimate. A p-value, when used, measures how unusual data at least as discrepant as those observed would be under a specified null model; it does not measure the probability that a treatment works or that the null hypothesis is true. The registry record reports no interval, p-value, or estimate for the primary endpoint.

The record specifies a mean and full range as the endpoint summary, but it does not describe a model for comparing groups or an adjustment strategy. No assumption checks, sensitivity analyses, or analysis of distributional features are reported. Since the actual time data are absent, it is not possible to assess whether a normal approximation for an analysis would be suitable. The normal approximation mentioned in the planning illustration is an assumption for that illustration, not proof that the outcome data followed a normal distribution.

For a procedure-time outcome, an analysis would also need to make clear how failed, incomplete, or unusually prolonged procedures were treated. The registry record does not report whether such events occurred or how they would be reflected in the endpoint. It also does not say whether timing was assessed by a single observer, recorded automatically, or checked for consistency. These are general methodological considerations; they are not evidence that any specific problem occurred in this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures and identifies procedure set-up and total time as the primary outcome. It names a secondary outcome concerning the cost of using cystoscopy versus DirectVision. The descriptions of the remaining measures and the intended hierarchy among outcomes are not reported in the registry record. The record also reports no analyses, so it does not show which outcomes, if any, were analyzed or whether results were selected for reporting.

Multiplicity arises in general when investigators conduct several statistical tests or examine multiple outcomes, time points, or subgroups. Without a prespecified analysis plan, readers cannot determine whether statistical significance thresholds were adjusted or how confirmatory findings were distinguished from exploratory ones. The registry does not report a multiplicity adjustment, but that absence should not be read as evidence that a particular method was or was not used outside the registry.

Missing-data handling is not reported in the registry record. There is no account of missing procedure times, incomplete procedures, withdrawals, or exclusions from outcome analyses. The record lists enrollment as 5, but does not provide analysis populations for the primary endpoint or other outcomes. It is therefore not possible to assess whether participants were analyzed according to assignment, whether available cases were used, or whether missing outcomes were imputed.

In general, missing observations can affect an estimate if the likelihood of missingness is related to participant characteristics or outcomes. Transparent reporting would state how much outcome information was available, why any observations were missing, and how the analysis addressed them. No such information is reported for this study. The same limitation applies to baseline characteristics and protocol deviations: they are not described in the registry record, so their role in the analysis cannot be evaluated.

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 0% reporting threshold.

The registry adverse-event record reports zero serious adverse events in the cystoscopy group, with 2 at risk, and zero in the DirectVision group, with 3 at risk. It also reports zero other adverse events in each group and zero deaths in each group. These are the event counts recorded for the groups; they are not procedure-time results or evidence about comparative effectiveness.

In general, an observed count of zero means no events of that category were recorded among the listed participants at risk during the reporting period. It does not establish that an event is impossible or that the procedures have identical safety profiles. With a small number of participants, uncommon or delayed events may not be observed, and the registry does not provide follow-up duration or detailed event definitions. The absence of recorded events should therefore be interpreted narrowly.

The registry record does not report further details about how adverse events were collected, whether all participants were followed for the same duration, or whether any events led to withdrawal or altered procedure completion. The listed counts cannot support a precise comparison of risks. They describe what was recorded in the registry, not a complete assessment of safety in broader clinical use.

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

The record documents a randomized, parallel comparison of DirectVision and cystoscopy for urinary catheter placement, with procedure set-up and total duration named as the primary endpoint. It also documents that the study was terminated and that enrollment was recorded as 5. Those details describe the study and its status; they do not reveal which procedure took less time or whether either method was easier to use.

No primary endpoint results are reported in the registry record. There are no group-specific time summaries or uncertainty estimates to support a comparison. The record therefore does not establish that procedure times differ, that they are alike, or that either method is more effective. A missing result is not a null result: without the observed data and analysis, readers cannot distinguish an inconclusive comparison from an effect that was not measured or reported.

The safety record lists no serious or other adverse events and no deaths in the groups, with the stated numbers at risk. These observations are limited to the events recorded in this study. They do not rule out risks that might occur in a larger population or over a different follow-up period. The record provides no basis for clinical advice or for choosing one procedure over the other.

The registry rationale describes concerns associated with difficult catheterization and presents DirectVision as a visualization system. That rationale explains why a comparison could be of interest, but it is not evidence that the device prevents injury, improves placement, or changes patient outcomes. The posted results do not report a measure of successful placement, and no results are available for the named cost outcome.

The most defensible reading is narrow: a randomized study was registered, it was terminated, and the record does not present analyses of the primary endpoint. The planning illustration does not fill that gap. Any conclusion about procedure duration, effectiveness, ease of use, cost, or safety would require information not reported in the registry record.

13. Why This Trial Matters Statistically

This study raises a practical statistical question: how should a procedural device be compared with an established procedure when the intended outcomes include both time and ease of use? The registry identifies a concrete primary measure, set-up and total procedure time in minutes, and records randomization to the two methods. A clearly defined time endpoint can be useful for studying workflow, but it must be reported with enough detail to understand what was timed and how the groups were compared.

The record also illustrates why registration and results reporting serve different purposes. Registration identifies the planned comparison and outcome, while results allow readers to evaluate the observed data and their uncertainty. Here, the primary endpoint is named but its results and analysis are not reported in the registry record. Readers can identify the intended statistical question but cannot estimate the answer from the posted information.

Enrollment recorded as 5 makes precision a central concern even if outcome data were available. In general, estimates from small studies can be highly uncertain, and randomization does not prevent chance imbalance. The registry’s planning illustration describes assumptions but gives no calculated sample-size values. Its presence does not demonstrate that the study was adequately powered, and it should not be confused with evidence about the observed effect.

Finally, the study’s terminated status makes transparent reporting particularly important, while the reason for termination is not reported in the registry record. Without the endpoint data, analysis methods, missing-data account, and explanation of status, readers cannot determine what was learned or why reporting stopped. The statistical importance of this record is therefore as much about the limits of available evidence as about the comparison it set out to make.

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 main limitation for interpretation is that the registry record does not report primary endpoint results or any analysis results. The endpoint is described, but there are no observed procedure-time summaries or estimates of the comparison. This prevents assessment of both the direction and precision of any difference.

Enrollment is recorded as 5, and the record does not describe participant characteristics, eligibility criteria, or baseline comparability. The title identifies the study as single center, but further information about the setting and procedural teams is not reported. The registry does not explain how randomization was carried out, whether allocation was concealed, or whether all assigned procedures were completed.

No masking was used. For a procedural study, awareness of the assigned method may influence conduct or time measurement; the record does not say who measured the endpoint or whether the assessor was unaware of assignment. The endpoint description does not specify exact timing rules, treatment of incomplete procedures, or how the full range was calculated from the recorded observations.

The status is terminated, but the reason is not reported in the registry record. The record does not report an analysis plan, missing-data methods, analysis populations, protocol deviations, or the relationship between the listed outcome measures and any analyses. Although the record names a secondary cost outcome and lists 7 outcome measures, detailed results for these outcomes are not reported. These gaps limit interpretation of effectiveness, ease of use, costs, and safety beyond the recorded adverse-event counts.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: DirectVision for Urinary Catheterization — NCT03066999.
• Registry record last updated 2019-07-30; status last verified 2019-07.
• Results first posted 2019-07-30.
• 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

NCT03066999 is a randomized, parallel study with no masking, described in its official title as a prospective, single-center study. It compares catheter placement using DirectVision with catheter placement using cystoscopy. Enrollment is recorded as 5; the study began on 2017-03-07, reached primary completion on 2017-10-01, and has a terminated status. The sponsor is The Pur Clinic.

The primary endpoint is set-up and total procedure time, measured in minutes, with a mean and full range specified. A secondary outcome concerns cost. The record lists 7 outcome measures and reports no analyses. It does not report primary endpoint results, the reason for termination, or the statistical analysis plan.

The adverse-event record lists zero serious adverse events, zero other adverse events, and zero deaths in both groups. Those counts are limited to the participants and events recorded. The posted information does not establish a difference in procedure time, effectiveness, ease of use, cost, or broader safety.