Patient Satisfaction Study: Clean Intermittent Self-Catheterization Teaching: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Patient Satisfaction Study: Clean Intermittent Self-Catheterization Teaching (NCT00678444), a randomized na study. The primary outcome is State-Trait Anxiety Inventory-State Scores.

2. Clinical Question

3. Trial Design

The registry describes a randomized, parallel-group study with no masking. Its listed title concerns satisfaction with the timing of CISC teaching after prolapse or incontinence surgery, and its summary describes a comparison of anxiety and satisfaction between preoperative video instruction and no specific preoperative instruction. The study is listed as completed, with enrollment of 199. Its start is recorded as 2008-04 and primary completion as 2011-04; the sponsor is the University of Pittsburgh.

One arm was assigned not to watch an educational video about self-catheterization before surgery. The other arm was assigned to watch the educational video before surgery. The study summary describes the control condition as including basic informed consent about the risks of postoperative urinary retention, but no specific preoperative CISC teaching. The registry lists the intervention as an educational video.

Random allocation distinguishes the intended study groups by assignment rather than by participant choice. A parallel design means that participants were assigned to one arm, rather than crossing between the two study conditions. The record identifies no masking, so the groups were not described as blinded. Whether outcome assessors or analysts were masked is not reported in the registry record.

The primary outcome is a continuous anxiety score measured at several points around teaching and surgery. The secondary outcome is patient satisfaction, described as visual analogue scores. Details of the randomization procedure, allocation concealment, the exact timing of each assessment other than the listed timepoints, and the planned statistical model are not reported in the registry record. The record gives no single primary timepoint comparison or numerical results from which to describe the estimated group difference.

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.

Overall Study

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 State-Trait Anxiety Inventory-State Scores, measured over Baseline, after viewing educational video, after learning self-cathterization, 6 weeks post-operatively.

The primary endpoint is the State-Trait Anxiety Inventory-State score, abbreviated STAI-S. It is intended to measure situational anxiety: current feelings related to bladder catheterization, rather than a person's more general or enduring tendency toward anxiety. The registry describes a 20-item, Likert-type validated measure, scored from 20 to 80, with higher scores reflecting higher situational anxiety. Responses concern feelings such as being at ease or upset about bladder catheterization.

Repeated measurements can describe anxiety at different stages: baseline, after viewing the educational video, after learning self-catheterization, and 6 weeks post-operatively. These timepoints are relevant to the study question because the intervention is preoperative teaching and the outcome concerns feelings about catheterization. A score at one timepoint and a change over time answer different questions, so the choice of comparison matters. The registry record does not identify one timepoint as the sole primary comparison or report numerical scores for any timepoint.

Patient satisfaction is listed separately as a secondary outcome, measured with visual analogue scores. The registry record does not describe the specific satisfaction scale or report its results. The stated purpose of the STAI-S is to assess current anxiety, which makes it conceptually distinct from satisfaction: anxiety scores and satisfaction scores should not be treated as interchangeable measures.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Interpretation of this study depends on distinguishing the planned comparison, the measurement schedule, and the estimates actually reported. The registry describes randomized assignment to a preoperative educational video or no specific preoperative CISC instruction. It names a continuous primary measure and several assessment times, but does not report an analysis of those measurements. Explanations of statistical concepts in this discussion are general; they do not describe methods that the investigators are known to have used unless the registry record says so.

What a mean and standard deviation describe

The primary outcome is specified as a mean with standard deviation. In general, a mean describes the central level of a continuous measure across participants, while a standard deviation describes how spread out individual scores are around that mean. They answer different questions: a group can have a similar average to another group but more variation in individual scores. The registry record provides no STAI-S means or standard deviations by arm or measurement time, so the distribution and average anxiety level cannot be characterized from the posted results.

A difference between group means is one possible summary for a continuous outcome. For repeated measurements, analysts might compare groups at a particular time, compare change from baseline, or use a model that incorporates multiple timepoints. These approaches target related but not identical quantities and can use the available observations differently. The registry record does not state which approach was planned or used. No adjusted or unadjusted effect estimate is reported.

Why confidence intervals matter

In general, a confidence interval expresses the uncertainty around an estimated effect under the assumptions of the statistical method. Its location describes which effect values are compatible with the data and method, while its width conveys precision. A narrow interval indicates more precision than a wide interval, but interpretation also depends on the outcome scale and the size of effects that would matter in context. Since no estimate or confidence interval for STAI-S is reported in the registry record, neither the direction nor the precision of a group contrast can be assessed.

A p-value, in general, measures how unusual data at least as inconsistent with a specified null model would be if that model and the analysis assumptions held. It does not measure the probability that the null hypothesis is true, the magnitude of an effect, or whether a difference matters to participants. The record does not report p-values for the outcomes. A missing p-value is not a finding of no difference, and it cannot establish that the arms were equivalent.

Repeated outcomes and multiplicity

Multiple timepoints create more than one possible comparison. If investigators test several outcomes or timepoints, the chance of obtaining at least one apparently noteworthy result can increase when no adjustment or prespecified testing strategy is used. This is the general multiplicity concern. It can be addressed in different ways, such as specifying a primary contrast in advance or applying an appropriate adjustment, but the suitable approach depends on the study question and analysis plan. The registry record does not report a multiplicity strategy or identify a single primary timepoint contrast. It also lists satisfaction as a secondary outcome, adding another outcome domain to consider when interpreting a set of tests.

Repeated observations on the same participant are generally correlated rather than independent. A statistical model that accounts for this within-participant relationship can be useful when estimating patterns across time. Different models make different assumptions about the correlation and about how missing observations are handled. The registry record does not report a repeated-measures model, its assumptions, or any model diagnostics. It would be inappropriate to infer a particular method merely from the fact that multiple timepoints were recorded.

What the planning illustration means

The registry describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The illustrations consider detecting a stated fraction of the observed effect. These are planning calculations, not observed study results and not observed power. The record's enrollment of 199 is the study enrollment; it should not be confused with a calculated number of participants per arm for a hypothetical future design. The effect estimate used in the illustration and the resulting planning counts are not reported in the registry record for this explanation, so no planning count can be stated.

In general, a sample-size calculation depends on the effect selected for detection, the variability of the outcome, the significance level, desired power, allocation, and analysis assumptions. A calculation based on an observed effect is particularly dependent on that estimate; uncertainty in the observed effect can make a planning illustration unstable. It does not establish the actual power of a completed trial. The registry does not report the original design's sample-size justification, its assumptions, or whether the enrolled number was chosen to meet a particular target.

Overall, the methods information establishes the broad design and endpoint but leaves major elements of the analysis unspecified. The statistical model, exact contrast, missing-data approach, multiplicity handling, and analysis population are not reported in the registry record. Without outcome estimates and their uncertainty, the statistical evidence for the primary and secondary questions cannot be evaluated from these record details.

10. Multiplicity, Missing Data and Analysis Populations

The primary anxiety outcome is recorded at baseline, after viewing the educational video, after learning self-catheterization, and 6 weeks post-operatively. Patient satisfaction is also listed as a secondary outcome. Several timepoints and outcome domains create a multiplicity issue in general: interpretation depends on which comparisons were prespecified and whether the analysis accounted for testing more than one contrast. The registry record does not report a multiplicity plan, a hierarchy of comparisons, or a correction method. It also does not identify one anxiety timepoint comparison as the single primary contrast.

Missing outcome data can affect both the number of participants analyzed and the interpretation of an estimate. The registry record does not report how many participants completed each STAI-S assessment, how much data were missing, why any data were missing, or how missing values were handled. It does not state whether the analysis used observed cases, imputation, or a model intended to use incomplete repeated measurements. These methods make different assumptions, so the absent details limit assessment of possible bias and precision.

The record also does not define the analysis population, such as whether participants were analyzed according to their randomized assignment or according to the instruction they received. Randomization describes how the arms were assigned; it does not by itself identify which participants were included in a particular outcome analysis. No analysis counts are reported for the outcome comparisons. Accordingly, the extent to which the outcome analyses retained the randomized groups cannot be determined from the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports no serious adverse events affecting participants in either group: 0 of 100 at risk in the non-educational-video group and 0 of 99 at risk in the educational-video group. For the separate category labeled other adverse events, the record lists 34 affected among 93 at risk in the non-educational-video group and 32 among 91 at risk in the educational-video group. Death counts are not reported in the registry record.

These figures should be read with their denominators, which differ between the serious-event and other-event categories and between groups. The record does not explain why the at-risk counts differ from the enrollment-arm counts, define the other-event category, describe event types or severity, or give an adverse-event observation period. Counts alone do not establish a causal relationship with the video or surgery, and they do not measure anxiety or satisfaction. The absence of reported serious events in these categories should not be interpreted as proof that no harms occurred beyond what the registry captured.

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

The study addresses a focused question about the timing of CISC teaching: whether preoperative instruction by educational video was associated with anxiety and satisfaction outcomes around prolapse or incontinence surgery. Its randomized, parallel-group design makes assignment to video instruction the central contrast. The primary measure is situational anxiety related to bladder catheterization, with assessments at several stages, and satisfaction is listed as a secondary outcome.

What the registry record does not provide is the numerical evidence needed to answer the comparison. No group-level STAI-S scores, group differences, confidence intervals, or significance tests are reported. Satisfaction scores and their analysis are also absent. Without those results, it is not possible to describe the direction, size, or precision of any association, or to determine whether the groups' outcomes were similar or different. This is a limit of the information in the record, not evidence that the intervention had no effect.

The study enrollment and safety counts do not fill this gap. Enrollment indicates how many participants entered the study, while outcome denominators would indicate how many contributed data to each assessment. The latter are not reported. Safety categories provide counts of recorded events, not patient-reported anxiety or satisfaction and not an estimate of the primary endpoint.

The findings also cannot be extended beyond the population and intervention described in the record without additional evidence. Details of eligibility, video content, care outside the teaching assignment, and the outcome analysis are not reported. No conclusion about the clinical value of teaching, or advice about individual care, follows from the study description alone. A statistical interpretation of efficacy or comparative outcome would require the outcome estimates, uncertainty, analysis details, and relevant context, none of which is reported for the patient-reported endpoints.

13. Why This Trial Matters Statistically

This trial is statistically interesting because its question concerns both an educational intervention and the timing of an outcome that may change during a participant's experience of surgery and self-catheterization. Anxiety was assessed across multiple stages, rather than only at one moment. That schedule raises a central design and analysis issue: whether the scientific target is an arm difference at a particular time, a change from baseline, or a pattern across the full course of measurements. Those targets should be distinguished before results are interpreted.

The randomized parallel design gives the study a clear intended comparison between participants assigned to watch the video and those assigned not to watch it. But the design alone does not establish what the outcome estimates are, how precisely they were estimated, or whether the analysis preserved the randomized comparison. The record's lack of numerical results and analysis details therefore matters: a reader cannot assess effect size, uncertainty, attrition, or robustness from the listed design features alone.

The endpoint also illustrates why measurement choice matters. STAI-S is described as measuring current, catheterization-related anxiety, while satisfaction is a different secondary construct. Treating these as distinct outcomes preserves the intended interpretation. The multiple anxiety timepoints and secondary satisfaction outcome also make the prespecified analysis and multiplicity approach important, yet these details are not reported.

Finally, the safety record illustrates the need to read counts with their denominators and category definitions. The listed at-risk totals vary by event category, while the registry does not explain that variation. Such detail affects what comparisons can be made. Overall, the record provides a useful outline of the question and design, but its statistical contribution cannot be judged from design labels or adverse-event counts in the absence of reported patient-reported outcome estimates.

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.

A key limitation for interpreting this specific study is the absence of numerical results for its primary and secondary patient-reported outcomes. The registry identifies STAI-S and visual analogue satisfaction scores but does not report their group values or comparative estimates. As a result, neither effect direction nor magnitude and precision can be assessed. This prevents a statistical conclusion about the stated anxiety and satisfaction questions.

The primary measure is described at multiple timepoints, but the record does not specify which timepoint or contrast was intended to anchor the main inference. It does not report whether analysis focused on follow-up scores, change from baseline, or a trajectory over time. The registry also does not state how repeated measurements were modeled. These omissions make it difficult to understand what estimand the investigators intended to estimate.

Information needed to assess completeness is also absent. Outcome-specific participant counts, missing-data reasons, the approach to missing observations, and the analysis population are not reported in the registry record. The randomized enrollment total therefore cannot be assumed to equal the number analyzed at every timepoint. The safety denominators are not substitutes for those outcome-specific counts.

Other protocol and reporting details are unavailable, including the method for generating and concealing random assignments, the extent of masking beyond the listed absence of masking, the video content, and the multiplicity plan. The registry record does not report the original sample-size justification or statistical analysis plan. Its planning illustration is not a substitute for those details or for observed outcome estimates. These limitations arise from what is reported in the registry record; they do not establish that unreported methods or analyses were not conducted.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Patient Satisfaction Study: Clean Intermittent Self-Catheterization Teaching — NCT00678444.
• Registry record last updated 2018-08-03; status last verified 2016-10.
• Results first posted 2018-08-03.
• 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

NCT00678444 is a completed randomized, parallel-group study sponsored by the University of Pittsburgh, with enrollment of 199 and no masking listed. It compared preoperative educational-video instruction about clean intermittent self-catheterization with no specific preoperative instruction beyond basic informed consent concerning postoperative urinary retention.

The primary outcome was State-Trait Anxiety Inventory-State score at baseline, after viewing the video, after learning self-catheterization, and 6 weeks post-operatively. Patient satisfaction measured with visual analogue scores was secondary. Numerical outcome results, analysis details, outcome-specific denominators, missing-data handling, and a multiplicity plan are not reported in the registry record. Serious adverse events affected 0 of 100 and 0 of 99 participants at risk in the two groups, respectively; other adverse events affected 34 of 93 and 32 of 91 at risk. Death counts are not reported.