Effect of Vulvar Re-Antisepsis Before CO₂ Cystoscopy Performed After Laparoscopic Hysterectomy on Postoperative Urinary Infections: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Vulvar Re-Antisepsis Before CO₂ Cystoscopy Performed After Laparoscopic Hysterectomy on Postoperative Urinary Infections (NCT07232446), a registered phase not stated study. The primary outcome is Number of Participants Who Developed a Postoperative Urinary Tract Infection According to CDC/NHSN Criteria.

2. Clinical Question

The clinical rationale described in the record is that vaginal flora could contaminate the cystoscope and potentially contribute to postoperative infection. That rationale motivates the comparison; it is not evidence that contamination occurred or that either antisepsis approach changed infection risk. The record describes an observational study, and the allocation method is not stated. Therefore, the groups should not be treated as a randomized comparison or assumed to be comparable in all respects.

3. Trial Design

The registry describes a prospective observational study of patients undergoing total laparoscopic hysterectomy for benign indications. It compares routine preoperative vulvar antisepsis alone with routine antisepsis followed by additional vulvar re-antisepsis immediately before cystoscopy. In both groups, cystoscopy is performed at the end of the hysterectomy using carbon dioxide as the distension medium. The record gives an enrollment of 98 and lists 53 participants at risk in the Standard Antisepsis group and 45 at risk in the Re-Antisepsis Before Cystoscopy group in the adverse-event information.

The record does not state how participants were assigned to the groups. It therefore does not establish that the comparison was randomized, nor does it describe a procedure for matching or adjusting the groups. The registry itself cautions that the arms are not a like-for-like control comparison. Differences in outcomes, if reported, could reflect differences between the groups as well as the re-antisepsis step; the record does not provide information to separate those explanations.

The primary outcome is the number of participants who develop a postoperative UTI meeting CDC/NHSN criteria, with follow-up described as up to 6 weeks after surgery. The recorded secondary outcome is total time required for cystoscopy, including the re-antisepsis step. The brief study description also mentions catheterization time and postoperative antibiotic therapy as secondary outcomes, but the record does not give results for them or explain the difference between that description and the listed outcome measure.

The registry status is COMPLETED. Completion status does not itself supply the missing outcome results. The record lists no statistical analyses, and the statistical analysis plan, participant flow, baseline characteristics, and handling of missing observations are not reported in the registry record.

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 Number of Participants Who Developed a Postoperative Urinary Tract Infection According to CDC/NHSN Criteria, measured over Up to 6 weeks after surgery.

The primary endpoint counts participants who develop a postoperative urinary tract infection within 6 weeks after total laparoscopic hysterectomy. The definition requires urinary symptoms and/or signs consistent with UTI together with laboratory confirmation by urine testing or culture. Asymptomatic bacteriuria is explicitly excluded. The registry says diagnosis is based on clinical follow-up evaluations, electronic medical records, and microbiology reports.

This endpoint is used to capture clinically identified infections rather than laboratory findings alone. Requiring symptoms and/or signs alongside laboratory confirmation distinguishes the recorded outcome from asymptomatic bacteriuria. The endpoint is relevant to the study question because the proposed intervention occurs immediately before cystoscopy, while the measured outcome is postoperative UTI during the stated follow-up period.

The endpoint description defines what was intended to be counted, but does not report how many participants met the definition in either group. Group-specific primary outcome results, an effect estimate, and its uncertainty are not reported in the registry record. The adverse-event counts should not be substituted for those missing endpoint results: the record presents them as safety information, not as the primary UTI outcome.

In general, a clearly specified outcome helps readers understand which events count and over what period they are assessed. It does not by itself show whether the outcome was measured consistently, whether all participants had complete follow-up, or whether observed group differences are attributable to the intervention. Those details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins by separating the question the study set out to answer from the results that are actually reported. The primary question concerns a binary outcome: whether each participant developed a qualifying postoperative UTI during the stated follow-up. The registry defines the outcome, but does not give group-specific counts or a comparative estimate. Without those results, the direction, magnitude, and uncertainty of the primary comparison cannot be described.

What does an observational comparison mean?

General explanation: In an observational study, participants are compared according to the groups recorded by the investigators, but random assignment is not established by the design description. If the groups differ in relevant characteristics, those differences can be associated with the outcome independently of the intervention. Statistical adjustment can sometimes address measured differences, but it cannot automatically remove unmeasured differences. In this record, allocation is not stated, the registry says the arms are not a like-for-like control comparison, and no analysis is reported. It is therefore not possible to determine whether any adjustment was used or whether the groups were comparable.

The intervention is an additional antisepsis step before cystoscopy, while the comparator receives standard preoperative antisepsis only. Because the added step is part of the procedure being compared, the listed secondary time outcome includes the re-antisepsis step in total cystoscopy time. A time comparison would therefore describe the time associated with the cystoscopy procedure as defined in the record, including that step. No time results are reported.

Why do event counts and estimates matter?

General explanation: For a binary outcome, event counts and the numbers of participants assessed in each group are basic inputs to an unadjusted comparison. An effect estimate describes the contrast between groups; an interval estimate describes uncertainty around that estimate. The choice of effect measure and statistical method should match the study question and design. The registry record does not report primary endpoint counts, an effect measure, or an interval, and its analysis count is 0. No primary statistical comparison can be reconstructed from the posted information.

A p-value, in general, measures how compatible the observed data are with a specified statistical model under a null hypothesis; it does not measure the probability that a treatment works, nor does it describe the size or clinical importance of an effect. A p-value is not reported for the primary endpoint. It would be inappropriate to infer statistical significance or nonsignificance from the safety counts, from the study’s completed status, or from the absence of a primary result.

How should uncertainty be understood?

General explanation: Confidence intervals communicate the range of effect values that are compatible with the observed data under the interval method and its assumptions. Wider intervals generally indicate less precision, while narrower intervals indicate greater precision. Precision depends on event information and the analysis, not only on the enrollment figure. Here, no primary effect estimate or confidence interval is reported, so neither the direction nor the precision of a primary comparison can be assessed.

The sample-size material is described as a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The stated convention is to detect a fraction of the observed effect; for time-to-event tables, the stated quantity is total events, while other tables give participants per arm. These are planning assumptions, not a statement of the trial’s original design justification or evidence of observed power. The registry record does not report the observed primary effect or the numerical planning outputs, so no particular planning target can be interpreted from the record.

What does over-dispersion mean in general?

General explanation: Over-dispersion occurs when observed variability is greater than a statistical model expects. It can make standard errors too small if a model assumes less variability than the data contain, leading to overconfident intervals or tests. The primary endpoint is recorded as a participant count for a binary outcome, and no statistical model or over-dispersion assessment is reported. This general concept should not be taken as a description of an analysis performed in this study.

The study’s observational design also matters for causal interpretation. An association between group membership and outcome, if reported, would not by itself show that the additional antisepsis step caused the difference. The registry record provides no reported statistical adjustment or causal analysis. The appropriate reading is therefore limited to the design and results actually documented, with the primary comparative results unavailable.

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("Standard Antisepsis", "Re-Antisepsis Before Cystoscopy")
n      <- c(53, 45)
events <- c(8, 4)
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  Standard Antisepsis  53  8  15.1  6.7  27.6  7.9  27.1  7.9  27.1
ARM  Re-Antisepsis Before Cystoscopy  45  4  8.9  2.5  21.2  3.5  20.7  3.6  20.8

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists the primary UTI endpoint and a secondary outcome concerning total cystoscopy time, including the re-antisepsis step. The brief study description also mentions catheterization time and postoperative antibiotic therapy as secondary outcomes, but the registered outcome list does not fully align with that description. No results for these secondary measures are reported, and the record does not clarify which outcomes were analyzed or how discrepancies between the descriptions were handled.

No statistical analyses are listed. The record does not report a prespecified testing hierarchy, an adjustment for multiple comparisons, or a plan for controlling the chance of false-positive findings across outcomes. General explanation: when several outcomes or comparisons are tested, the chance of at least one apparently notable result can increase if the analyses are treated as independent opportunities to find a difference. A prespecified hierarchy or multiplicity adjustment can help address that issue. Since analyses and test results are not reported, the impact of multiplicity cannot be assessed.

Missing-data methods and analysis populations are also not reported in the registry record. It does not state how participants without complete follow-up were handled, whether all enrolled participants were included in each outcome analysis, or whether any exclusions occurred. The listed at-risk figures in the adverse-event information do not establish the analysis population for the primary outcome. Without the outcome denominators and a participant flow account, completeness of primary endpoint follow-up cannot be evaluated.

The completed status does not answer these reporting questions. It indicates the registry status, but not whether all planned outcomes were collected, analyzed, or reported. The registry record does not report a statistical analysis plan, interim analyses, or a sample-size justification for the study design.

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 1% reporting threshold.

The adverse-event information lists zero serious adverse events, zero other adverse events, and zero deaths in the Standard Antisepsis group, among 53 participants at risk, and in the Re-Antisepsis Before Cystoscopy group, among 45 participants at risk. No serious adverse-event terms are listed. These are the safety figures recorded for the groups; they are not primary UTI outcome results.

General explanation: A zero count in a safety summary means that no event of the specified type is recorded in that summary. It does not establish that the event is impossible or that a group has no risk. The amount of uncertainty around a zero count depends on the amount and quality of observation, follow-up, and event ascertainment. The registry record does not provide further details on safety follow-up or completeness of adverse-event reporting.

The primary outcome uses a specific definition of postoperative UTI and a follow-up period of up to 6 weeks. Although a UTI could also be relevant to safety, the record presents its primary endpoint separately from the adverse-event summary. The adverse-event figures should therefore be read as safety reporting, not as evidence that no participant developed a UTI. The primary UTI counts and comparative results are not reported in the registry record.

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

The record establishes that investigators planned a prospective observational comparison of standard preoperative vulvar antisepsis with additional vulvar re-antisepsis immediately before cystoscopy. It defines postoperative UTI using CDC/NHSN criteria, excludes asymptomatic bacteriuria, and describes follow-up as up to 6 weeks after surgery. It also identifies total cystoscopy time, including the re-antisepsis step, as a secondary outcome.

What the record does not establish is whether the intervention group had fewer or more postoperative UTIs, or whether the groups differed at all. The primary outcome counts, effect estimate, and measure of uncertainty are not reported. As a result, the registry record cannot support a conclusion that additional re-antisepsis reduces infection, increases infection, or makes no difference. Missing comparative results should not be interpreted as a null result.

The safety information records zero serious adverse events, zero other adverse events, and zero deaths in each group. These figures describe the safety fields reported in the registry and do not replace the primary UTI outcome. Nor do they establish that all possible adverse outcomes were absent; the record does not provide detail on the completeness or duration of safety ascertainment.

The observational design places another boundary on interpretation. Allocation is not stated, and the registry warns that the arms are not a like-for-like control comparison. Thus, even a reported association would require cautious interpretation because the record does not describe group comparability or adjusted analyses. The study description explains why the comparison was considered, but a rationale is not a result.

The registry’s COMPLETED status indicates that the record is marked complete. It does not supply unreported outcome estimates or analysis details. The most defensible conclusion is that the clinical question and endpoint are documented, while the primary comparative evidence needed to answer the question is not reported in the registry record.

14. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the distinction between a well-defined research question and a reportable comparative result. The record describes a specific procedural contrast and a primary endpoint with diagnostic criteria and a follow-up period. Those elements let readers understand what investigators intended to compare. They do not reveal whether the groups’ outcomes differed.

The study also highlights why design information is essential when reading group comparisons. The registry describes the study as observational, leaves allocation unstated, and cautions that the arms are not a like-for-like control comparison. In general, these features limit how confidently a difference could be attributed to the intervention, particularly if group characteristics and adjustment methods are not reported.

Reporting the primary event counts, denominators, effect estimate, and uncertainty would be important for interpreting the clinical comparison. Without them, readers cannot judge the size or precision of any observed difference. The zero adverse-event figures are useful safety information as recorded, but do not answer the primary question about postoperative UTI.

The registry record also presents a reporting distinction between its brief description of secondary outcomes and its listed secondary outcome measure. Clear alignment among outcomes described, registered, analyzed, and reported helps readers assess whether findings address the planned questions. Here, the record does not explain the difference or provide secondary results.

Finally, the sample-size description is explicitly a planning illustration based on an observed effect, not the trial’s own design justification. Such illustrations can help frame future planning, but they are not observed power and cannot substitute for the missing primary outcome results. Overall, the statistical importance of this record lies in making both the defined question and the limits of the available evidence visible.

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 main limitation for interpreting this specific study is that the registry record does not report the primary UTI outcome counts by group, an effect estimate, or uncertainty around a comparison. The study is marked COMPLETED, but the primary result cannot be inferred from that status or from the adverse-event data.

The group allocation method is not stated. The registry identifies the study as observational and explicitly cautions that the arms are not a like-for-like control comparison. The record does not report baseline characteristics, participant flow, or statistical adjustment that could help readers assess differences between groups. These omissions prevent evaluation of comparability and limit causal interpretation.

The primary endpoint is defined, but the record does not report the number of participants assessed for that endpoint in each group or whether follow-up was complete. The at-risk counts in the safety information do not establish the primary endpoint denominators. Missing-data handling and analysis populations are not reported.

The outcome descriptions are not fully aligned: the brief summary mentions cystoscopy duration, catheterization time, and postoperative antibiotic therapy, while the registered secondary outcome list names total cystoscopy time including the re-antisepsis step. The record does not explain this difference or report secondary outcome results.

The record lists no analyses and does not report a statistical analysis plan, multiplicity approach, interim analyses, or the trial’s own sample-size justification. The planning description refers to an illustration based on an observed effect, but no observed primary effect or numerical planning outputs are reported in the registry record. These limitations mean that neither the comparative outcome nor the analytical choices can be fully evaluated.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effect of Vulvar Re-Antisepsis Before CO₂ Cystoscopy Performed After Laparoscopic Hysterectomy on Postoperative Urinary Infections — NCT07232446.
• Registry record last updated 2026-06-22; status last verified 2026-05.
• Results first posted 2026-06-22.
• 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

NCT07232446 is a prospective observational study marked COMPLETED. It compares standard preoperative vulvar antisepsis alone with additional vulvar re-antisepsis immediately before carbon dioxide cystoscopy at the end of total laparoscopic hysterectomy for benign indications. The registry lists an enrollment of 98.

The primary outcome is the number of participants with a postoperative UTI meeting CDC/NHSN criteria within 6 weeks after surgery. Asymptomatic bacteriuria is excluded from that definition. The record lists total cystoscopy time, including the re-antisepsis step, as a secondary outcome; its brief description also mentions catheterization time and postoperative antibiotic therapy.

The primary outcome results, comparative estimates, and statistical analyses are not reported in the registry record. Allocation is not stated, and the record cautions that the arms are not a like-for-like control comparison. Safety information lists zero serious adverse events, zero other adverse events, and zero deaths in each group; these figures are not primary UTI results.