Product Evaluation of a Newly Developed Intermittent Catheter.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Product Evaluation of a Newly Developed Intermittent Catheter. (NCT02966015), a na na study. The primary outcome is Number of Participants Successfully Able to Insert Catheter.

2. Clinical Question

The study aim is described as investigating navigation of the newly developed catheter. The primary outcome asks participants to evaluate how the catheter navigates through the urethra during insertion. Their response options range from “Very easily” to “Not possible,” including “Easily,” “Neither/nor,” “Difficultly,” and “Very difficultly.” The record therefore frames the question as a participant-reported assessment of insertion and navigation, converted into a binary success classification for the primary outcome.

This is a descriptive question about use of the test catheter, not a randomized comparison of the device against another catheter. Although the safety record separates users by catheter-use category, it does not establish that these categories were assigned as treatment groups or that primary outcomes were compared between them. The registry record does not report comparative effectiveness estimates, a control condition, or a hypothesis test for a difference between groups.

The primary outcome timeframe is 1 week. The record does not report a numerical primary result, the number of participants classified as successful, or the distribution of the response categories. As a result, it is not possible to determine from the registry record how often participants were able to insert the catheter or how their assessments were distributed.

3. Trial Design

The registry describes a completed, single-group device study of the Coloplast test catheter. Its stated aim was to investigate navigation of a newly developed catheter. The enrollment entry is 153. The listed condition is urinary incontinence, and the sponsor is Coloplast A/S. The study start and primary completion are both recorded as 2016-05.

The design is not described as randomized: allocation is listed as NA. Masking is listed as none, and the model is identified as single group. The record does not describe a concurrent control intervention for the primary question. It lists one intervention, the Coloplast test catheter, and says subjects used the new test catheter for 1 week. The trial is marked completed.

The safety information is divided into Tiemann/Coudé users and traditional sleeve catheter users. These descriptions do not change the single-group characterization of the primary study. The registry does not say that participants were randomized to those categories, nor does it present them as a like-for-like control comparison. Any difference between such categories would also require care in interpretation because the record does not describe how participants came to use each catheter type or whether other characteristics differed.

The registry record does not report detailed eligibility criteria, recruitment procedures, setting, participant characteristics, or a protocol for the order of catheter use. It also does not report the rationale for the enrollment target or how that target was determined. The study phase is listed as NA; further explanation of that entry is not reported in the registry record.

Because the design is single group and unmasked, the primary question is whether participants reported being able to insert and navigate the test catheter under the described use conditions. The design does not, by itself, estimate how the experience would compare with another catheter or establish that any observed response was caused by the device rather than other influences. The absence of a reported primary result further limits what can be concluded about the outcome.

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.

Inclusion Visit

Reasons for not completing this period:

Test 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.

Population: All the subjects enrolled in the study

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Successfully Able to Insert Catheter, measured over 1 week.

The primary endpoint is the number of participants successfully able to insert the catheter, with the unit specified as participants and the timeframe specified as 1 week. The success rule is based on a participant response to the question, “How did you find the catheter navigates through the urethra during insertion”. Responses are “Very easily,” “Easily,” “Neither/nor,” “Difficultly,” “Very difficultly,” and “Not possible.” Any response other than “Not possible” is counted as successful catheterization.

This endpoint turns an experience reported on an ordered response scale into a binary classification: successful insertion versus not possible. That can make the outcome straightforward to summarize as a participant count, but it also means that different experiences—from very easy to very difficult—are placed in the same success category. The binary result therefore does not preserve the full distinction between ease-of-use responses.

The endpoint is relevant to the stated study aim because it focuses on whether insertion and navigation were possible during use of the new catheter. It captures the participant’s assessment rather than an independently described technical measurement. The registry does not report additional rules for handling unanswered questions, repeated attempts, or incomplete assessments. It also does not report the observed number of successful insertions, so the endpoint’s result cannot be evaluated from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in the registry record is limited. It identifies a single-group study, one primary outcome measure, and zero analyses. It does not report a statistical analysis plan, a model for the primary endpoint, an estimate, a confidence interval, or a p-value. The explanations below describe general statistical concepts relevant to this kind of endpoint; they do not imply that these methods were used in the study.

How should a binary outcome be understood?

In general, a binary outcome places each assessed participant into one of two categories, such as success or failure under a prespecified rule. Here, the registry’s rule classifies any response other than “Not possible” as successful catheterization. A descriptive analysis could report the number in each category and the denominator assessed. If expressed as a proportion, the denominator and the handling of missing responses would need to be clear. The registry does not report the primary outcome count or denominator, so no such proportion can be interpreted.

The response options themselves contain more information than the binary classification retains. “Very easily” and “Very difficultly” both meet the stated success rule, even though they reflect different experiences. A separate presentation of response categories would preserve that distinction, but the registry record does not report those category counts. The binary endpoint should therefore be understood as a measure of possibility according to the study definition, not as a full measure of ease or acceptability.

What would a confidence interval convey?

In general, a confidence interval expresses the uncertainty around an estimate under the assumptions of the method used. For a binary outcome, an interval around a proportion can indicate how precisely the observed sample estimates the corresponding underlying proportion. Its width depends on the amount of information and the observed distribution, among other factors. An interval does not correct for bias in study design, missing outcomes, or an unrepresentative sample. No confidence interval for the primary outcome is reported in the registry record.

Because this is a single-group study, a confidence interval for a success proportion would describe uncertainty around that group’s result. It would not create a comparison with another catheter. A comparison would require a suitable comparator and a design and analysis that support interpreting differences between groups. No such primary endpoint comparison is reported.

What does the single-group design allow?

In general, a single-group study can describe outcomes observed among participants using an intervention. It cannot separate the intervention’s contribution from other influences as effectively as a randomized comparison. Participant expectations, prior experience, differences in how the device is used, and outcome assessment can matter, particularly when participants report their own experience and masking is absent. These are general considerations, not evidence that any particular influence affected this study.

The registry identifies no masking and a single-group model. It does not report a statistical adjustment strategy or a protocol for the primary assessment. The adverse-event categories do not establish a comparative design: the registry does not say that participants were assigned to Tiemann/Coudé or traditional sleeve catheter use for the primary outcome, and it does not report comparative primary results for those categories.

How should planning illustrations be read?

In general, sample-size planning estimates describe what a future study might require under specified assumptions. They are not observed outcomes and do not show the probability that the completed study detected an effect. The planning description in the registry specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it says the effect to detect is a stated fraction of the observed effect. For non-time-to-event outcomes, the stated convention is participants per arm for a power target; time-to-event planning uses a total number of events. These are planning conventions, not a description of the actual single-group study design.

The observed effect needed for that illustration is not reported in the registry record. Therefore, any planning figure based on it should be treated only as a planning illustration, not as evidence about the catheter’s performance or as observed power. Sample-size calculations depend on their assumptions, and changing the assumed effect or other design choices changes the planned requirement. The record does not report that these planning assumptions were the study’s own design assumptions.

Why does the analysis population matter?

In general, the analysis population defines which participants contribute to an outcome estimate. It may differ from enrollment if participants do not complete an assessment or if prespecified eligibility or analysis rules apply. For a participant count, a numerator without a clear denominator cannot establish the corresponding rate, and an enrollment entry alone does not show how many observations were analyzed. The primary outcome population is not described in the registry record, and the number analyzed is not reported.

Likewise, missing-data methods determine how incomplete outcome information is handled. Excluding incomplete responses, treating them as failures, or using another method can lead to different interpretations. The registry record does not report whether primary endpoint responses were missing or how missingness was handled. No method should be assumed.

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("Tiemann/Coudé Users", "Traditional Sleeve Catheter Users")
n      <- c(95, 58)
events <- c(82, 58)
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  Tiemann/Coudé Users  95  82  86.3  77.7  92.5  78.0  91.8  78.0  91.8
ARM  Traditional Sleeve Catheter Users  58  58  100.0  93.8  100.0  93.8  100.0  93.9  100.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and zero analyses. It does not report a multiplicity strategy, a hierarchy of outcomes, or adjustments for multiple testing. With only one listed outcome measure, the record still does not establish whether other analyses were planned or conducted; the number of reported analyses is zero. The statistical analysis plan and any prespecified testing strategy are not reported in the registry record.

The primary outcome population is left blank. Although the enrollment entry is 153, the record does not report the number assessed for the primary endpoint, the number included in an analysis, or a primary outcome denominator. It also does not state how many participants had missing or incomplete responses. The enrollment figure should not be substituted for an outcome denominator without that information.

Missing-data handling is not reported in the registry record. In general, missing responses matter when the probability of an unanswered assessment is related to the outcome or to participant characteristics. The approach to incomplete data can affect both an estimate and its uncertainty. No approach—such as excluding missing responses or assigning them to a particular category—can be inferred.

The registry also does not report analysis populations such as an intention-to-treat or per-protocol population. These terms should not be applied to the study without a documented definition. The record does not describe deviations from the intended catheter use, the timing or completeness of outcome assessments, or any rules for excluding participants. Consequently, the extent to which the listed enrollment corresponds to participants with evaluable primary outcomes is unknown.

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 5% reporting threshold.

The adverse-event record lists Tiemann/Coudé users and traditional sleeve catheter users separately. For Tiemann/Coudé users, the record lists 95 at risk and 0 serious adverse events, 0 other adverse events, and 0 deaths. For traditional sleeve catheter users, it lists 58 at risk and 0 serious adverse events, 0 other adverse events, and 0 deaths. No top serious-event terms are listed.

These are the event figures reported for the two named categories. They should not be read as a randomized safety comparison: allocation is listed as NA, and the study model is single group. The record does not explain how participants came to be represented in each safety category or whether the categories overlap with the primary endpoint population.

Zero recorded events in these entries means that the registry reports none in the specified event fields for the listed categories. It does not establish that all possible adverse experiences were assessed or that the risk of an event is absent. The registry does not report event definitions, the collection method, follow-up details for safety, or a narrative describing how events were solicited and classified. These missing details limit interpretation of the zero counts.

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

The record describes an evaluation of whether participants could insert and navigate a newly developed intermittent catheter during use over 1 week. It defines success as any response other than “Not possible” to a question about navigation through the urethra during insertion. This definition clarifies what the intended primary endpoint represents: possibility of insertion under the study rule.

The record does not report the primary endpoint result. It therefore cannot establish how many participants met the success definition, how common each response was, or how precisely any estimate was measured. The listed enrollment is not a substitute for a reported outcome denominator, and the registry does not state how many participants contributed primary endpoint data.

Even if a success count were available, the endpoint would not by itself describe the full range of experience. Participants who found insertion very difficultly would be categorized as successful if they did not select “Not possible.” The record does not report the separate response categories, so it cannot show the distribution of ease or difficulty.

The study’s single-group, unmasked design does not provide a randomized comparison with another catheter. The safety categories do not supply such a comparison for the primary outcome. The record consequently does not support a comparative claim about the test catheter or a causal conclusion about differences from other devices.

The reported zero adverse-event counts are limited to the serious-event, other-event, and death entries within the named safety categories. They should be interpreted as registry entries, not as evidence that all safety concerns are absent. Overall, the record is informative about the study’s stated purpose and outcome definition, but its missing primary result, denominator, and analysis details leave the central outcome question unanswered.

14. Why This Trial Matters Statistically

This study is statistically instructive because its primary question sounds simple—whether insertion was possible—but the operational definition determines exactly what the result would mean. Treating every response other than “Not possible” as success creates a binary endpoint that combines a wide range of experiences. A reader needs both the rule and, where available, the underlying response distribution to understand what the count captures.

The record also illustrates why enrollment and analysis denominators are not interchangeable. An enrollment entry of 153 does not tell readers how many participants answered the primary question or how missing responses were treated. Without the result count and denominator, even a basic descriptive summary cannot be interpreted. Clear reporting of the analysis population and missing-data approach is essential for a participant-count endpoint.

Design context matters as well. A single-group evaluation can describe reported use, but it does not estimate a randomized difference against another catheter. The safety categories in the record should not be mistaken for assigned comparison groups. That distinction helps prevent descriptive group labels from being given a causal or comparative interpretation the design does not support.

Finally, planning calculations and observed trial results answer different questions. The registry’s planning description specifies assumptions for illustrations, while the primary outcome result and observed effect are not reported. A planning value cannot fill that evidentiary gap or be interpreted as observed power. The record therefore highlights the need to distinguish study design, outcome definitions, analysis information, and outcome findings when reading a clinical study.

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 most important limitation of the registry record for interpreting this study is that it does not report the primary endpoint result. The number of participants able to insert the catheter, the number assessed, and the distribution of response categories are absent. Without those data, the study’s central descriptive question cannot be answered from the record.

The primary outcome population is not described, and missing-data handling is not reported. The enrollment entry of 153 cannot establish the endpoint denominator. The record also does not explain whether participants completed the full 1-week use period, how assessments were collected, or how incomplete responses were classified.

The single-group design has no reported randomized comparator for the primary outcome, and masking is listed as none. Thus, the design does not provide a controlled estimate of how the experience compares with another catheter. The registry does not describe participant characteristics, eligibility criteria, or how the safety categories relate to the primary outcome population. These omissions make it difficult to assess who the results would represent even if the outcome result were available.

The endpoint collapses responses from “Very easily” through “Very difficultly” into the same success category, as long as the response is not “Not possible.” This is consistent with the stated rule but limits what the binary endpoint alone can say about ease of use. The response-category results are not reported.

Safety entries show zero serious adverse events, zero other adverse events, and zero deaths for each listed category, but the record does not report event definitions, ascertainment methods, or further safety context. These reporting limitations prevent a detailed safety interpretation. The analysis plan, multiplicity approach, and rationale for enrollment are also not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Product Evaluation of a Newly Developed Intermittent Catheter. — NCT02966015.
• Registry record last updated 2018-02-28; status last verified 2018-02.
• Results first posted 2017-12-08.
• 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

NCT02966015 is a completed, single-group device study titled “Product Evaluation of a Newly Developed Intermittent Catheter.” Coloplast A/S is listed as sponsor. The condition is urinary incontinence, enrollment is 153, and the study start and primary completion are both recorded as 2016-05. Masking is listed as none, allocation as NA, and the study model as single group.

Participants used the Coloplast test catheter for 1 week. The primary outcome concerns the number of participants successfully able to insert it, with success defined as any response other than “Not possible” to the navigation question. The registry record does not report the primary endpoint result, its denominator, or an analysis.

The safety record lists Tiemann/Coudé users and traditional sleeve catheter users, with zero serious adverse events, zero other adverse events, and zero deaths in each category. The record does not establish these categories as randomized comparison groups. It also does not report missing-data methods, analysis populations, a multiplicity strategy, or the rationale for the enrollment target.