Prospective Randomized Controlled Trial of Obstructed Defecation Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Prospective Randomized Controlled Trial of Obstructed Defecation Surgery (NCT05747027), a randomized na study. The primary outcome is Degree of Rectal Hypermobility Measured Via Ultrasound.

2. Clinical Question

The PROD trial was designed to compare laparoscopic abdominal ventral rectopexy with transvaginal sacrospinous rectopexy in people being treated for obstructed defecation associated with pelvic organ prolapse. Its central question was whether the procedures differed in their effect on rectal hypermobility, measured by ultrasound as a compression ratio at 24 months after surgery. The registry description also frames the research around symptom improvement and patient experience, with postoperative assessments that included symptom evaluation, pelvic examination and transvaginal pelvic ultrasound.

These questions matter statistically because a randomized comparison can estimate differences between treatment groups when outcomes are collected and analyzed as planned. In this record, however, the primary measurements were not completed because the study ended early. No primary comparison is reported, so the stated question remains unanswered by the posted results. The record also does not report comparative results for the secondary outcomes.

3. Trial Design

The registry describes the study as a prospective randomized controlled trial with a parallel-group design. Participants were to be randomized to one of two procedures: laparoscopic abdominal ventral rectopexy or transvaginal sacrospinous rectopexy. The record lists masking as none, so this was an open-label design rather than a masked comparison. The randomization sequence, allocation concealment procedures and intended allocation ratio are not reported in the registry record.

The listed enrollment is 15. The record gives a study start date of 2024-05-16 and a primary completion date of 2025-05-30, and the study status is terminated. It does not report why the study was terminated. The primary outcome was intended to be measured at 24 months post-operatively, but the record states that these measurements could not be completed due to early termination. The planned follow-up schedule also included office visits at 2-weeks, 2-, 12- and 24-months after surgery, with symptom evaluation, pelvic examination and transvaginal pelvic ultrasound.

Secondary outcomes named in the record include postoperative pain measured by pain scale and pain medication use, functional activity level, global improvement in bladder function, PFDI subscales for prolapse, colorectal-anal and urinary symptoms, and quality of life measured by PFIQ. The record lists 12 outcome measures but no statistical analyses. Detailed eligibility criteria, the intended recruitment target beyond the listed enrollment, and procedures for handling withdrawals are not reported in the registry record. The trial is listed with phase NA.

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

Analysis population for the primary outcome, as defined in the registry: Due to the early termination of the study, the 24-month post-operative primary outcome measurements could not be completed.

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 Degree of Rectal Hypermobility Measured Via Ultrasound, measured over 24 months post-operatively.

The primary endpoint was the degree of rectal hypermobility measured via ultrasound at 24 months post-operatively. The description specifies the compression ratio as the ultrasound measure. The outcome concerns movement or mobility of the rectum as assessed by the imaging procedure; the registry does not provide a unit, a definition of how the ratio is calculated, or a threshold for interpreting its values.

As a general statistical concept, a prespecified primary endpoint gives a trial a main outcome around which its principal comparison can be organized. A quantitative imaging measure can represent an anatomical feature in a way that may be compared between randomized groups, provided the measurement is collected consistently and its meaning is clearly defined. Interpretation would ordinarily depend on the observed values, their variability, the estimated between-group difference and uncertainty around that estimate.

None of those primary outcome results is reported in the registry record. The record explicitly says that the 24-month measurements could not be completed because of early termination. Consequently, there is no reported estimate of the compression ratio in either group and no reported comparison of rectal hypermobility between the procedures. The rationale for selecting this ultrasound measure over other possible measures is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a randomized, parallel-group trial with no masking. Randomization is a general method for assigning participants to groups by chance. Its statistical purpose is to reduce systematic differences between groups at the start of a study, so that a later comparison can be interpreted as an estimate of the effect of assignment to the procedures, subject to the trial’s conduct and data completeness. Randomization does not guarantee that groups will be alike in every characteristic, particularly when the number of participants is limited. The record does not describe the randomization procedure, allocation concealment or allocation ratio.

What would the primary comparison estimate?

The planned primary outcome was ultrasound-measured rectal hypermobility, described as the compression ratio, at 24 months post-operatively. In a completed analysis, a comparison would ordinarily summarize the outcome in each randomized group and estimate the between-group contrast. The registry does not specify whether the intended contrast was a difference in means, a different summary of a quantitative measure, or another statistic. It also does not report a unit, measurement definition beyond the compression ratio, or analysis model. These details are not reported in the registry record and should not be inferred from the endpoint name.

As a general concept, an estimate gives the observed magnitude and direction of a contrast, while its standard error and confidence interval describe uncertainty. A p-value, when used, summarizes how unusual data at least as incompatible with a specified null hypothesis would be under the model assumptions. It does not measure the probability that a treatment effect is true, and it does not describe the size or clinical importance of an effect. No trial-specific effect estimate, confidence interval or p-value is reported, so these concepts cannot be applied to a numerical comparison between the procedures.

Why does early termination matter?

The registry states that primary measurements at 24 months could not be completed because the study was terminated early. A randomized design can only answer its outcome question if the relevant measurements are collected and made available for analysis. When measurements are absent, the resulting evidence may be too incomplete to estimate the planned contrast. Missing outcome values can also make a comparison less precise and, depending on why values are missing, can introduce bias. The record does not report how many measurements were missing at earlier visits, reasons for missingness, or any statistical method for handling missing data.

The record lists 12 outcome measures and no analyses. This does not establish that no analysis was planned; it means no analysis is listed in the registry record. The statistical analysis plan, including any model for repeated follow-up measurements, adjustment variables, treatment of protocol deviations, or method for choosing an analysis population, is not reported in the registry record.

What do the safety counts represent?

The adverse-event entries separately report serious events, other events and deaths, with groups identified by randomized procedure or as unassigned. As a general statistical principle, event counts should be interpreted with their denominators and with attention to how long participants were observed. A zero count is a description of the registry data, not proof that the underlying event risk is zero. The record does not report event definitions, collection procedures, follow-up duration for safety, or additional detail about the unassigned group.

What about precision and planning?

General statistical planning uses assumptions about the effect worth detecting, variability, significance level, power and allocation. Those assumptions help define how much information a proposed study may need; they do not describe the precision actually achieved. The registry record does not report its own sample-size justification or a planned power calculation. Its notes describe planning illustrations based on a fraction of an observed effect, with a two-sided significance level of 0.05 and equal allocation assumptions, but no completed primary effect is available in the record to interpret as a trial result. Any such illustration is a planning exercise, not observed power and not evidence about the treatment comparison.

10. Multiplicity, Missing Data and Analysis Populations

The record lists the primary ultrasound outcome and a range of secondary outcomes, including pain, functional activity, bladder function, pelvic floor distress subscales and quality of life. When a study assesses several outcomes, multiplicity is a general statistical concern: repeated testing can increase the chance that at least one result appears noteworthy by chance. A prespecified plan may address this by defining a primary outcome, prioritizing secondary outcomes, or adjusting interpretation or testing. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or which secondary comparisons were intended to be confirmatory.

The record lists no statistical analyses, and it reports no comparative results for the primary or secondary outcomes. The reason is especially consequential for the primary endpoint: its 24-month measurements could not be completed because of early termination. Secondary outcome collection and analysis status are not reported in the registry record. The record does not describe the amount or pattern of missing data, reasons for missingness, imputation methods, or sensitivity analyses.

The analysis populations are also not described. The record does not report whether participants would be analyzed according to randomized assignment, treatment received, or another defined group, nor does it give numbers analyzed for each outcome. The randomized groups and an unassigned safety group are listed, but the basis for the unassigned classification is not reported. Without these details, readers cannot assess how participant inclusion, missing follow-up or multiplicity would affect any comparative estimate. These omissions are distinct from the missing primary measurements themselves: even a fully specified analysis plan would not substitute for the unavailable endpoint data.

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 reports no serious adverse events and no other adverse events in either named treatment group. For laparoscopic abdominal ventral rectopexy, 5 participants are listed as at risk, with 0 serious and 0 other events and 0 deaths. For transvaginal sacrospinous rectopexy, 6 are listed as at risk, with 0 serious and 0 other events and 0 deaths. The unassigned group lists 4 at risk, also with 0 serious events, 0 other events and 0 deaths.

These are descriptive registry counts. A zero count means no events in that category were recorded for the group as reported; it does not establish that the true risk is absent. General interpretation of safety counts also depends on how events were defined and collected, how long participants were followed, and whether all relevant participants contributed complete safety information. Those details are not reported in the registry record. The reason for the unassigned classification is also not reported. The small listed group sizes and unavailable information about observation and completeness limit what can be concluded from the absence of recorded events. The counts do not constitute a comparative safety analysis.

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

The registry record documents a randomized trial intended to compare two rectopexy procedures for obstructed defecation in pelvic organ prolapse. It identifies a clear primary measurement—ultrasound-assessed rectal hypermobility at 24 months after surgery—and names additional outcomes concerning symptoms, pain, function and quality of life. The record also describes planned postoperative visits and examinations. These features establish the intended scope of the research, not its comparative findings.

The main result is that the planned primary measurements were not completed after early termination. No estimate comparing the procedures is reported, and no secondary outcome analyses are listed. The registry record therefore does not show whether one procedure had greater or lesser rectal hypermobility, symptom improvement, pain, functional activity, bladder improvement or quality of life than the other. It also does not establish that the procedures had equal outcomes. Missing comparative results leave those questions unresolved in the posted record.

The safety entries report zero serious and other adverse events and zero deaths in the listed groups. Those counts describe the events recorded, but the record lacks enough information about follow-up duration, event collection and participant completeness to support a broad safety conclusion. In particular, zero recorded events should not be translated into a claim that no risks exist.

As a general distinction, a trial’s design specifies the comparison it aims to make, while results require observed outcome data and an analysis. Randomization alone does not produce an effect estimate, and a planned endpoint does not become a finding if it is not measured. The registry record supports describing the trial’s intended question and its reported status and counts. It does not support claims about comparative efficacy, equivalence, or definitive safety. The reason for termination and the statistical plan are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial raises a useful statistical issue: a carefully framed randomized comparison can remain unanswered when the outcome measurements needed for its primary question are not completed. The registry identifies two procedures, a randomized parallel-group design and a specific ultrasound measure at 24 months. Those features describe a testable comparison, but the early termination prevented completion of the primary measurements. The distinction between the planned design and the available evidence is essential when interpreting trial records.

The listed enrollment is 15, and the safety groups include an unassigned category. In a small study, estimates can be imprecise even when measurements are complete; missing endpoint data further limit the information available. As a general principle, precision depends on both the amount of data and the variability of the outcome. Because this record reports no primary outcome values or analysis, precision cannot be quantified for the intended comparison.

The record also illustrates why multiplicity and analysis populations matter when a study includes a primary measure and multiple secondary outcomes. A transparent plan can clarify which questions are primary, how secondary results should be interpreted, and which participants contribute to each analysis. Such a plan is not reported in the registry record, and no analyses are listed. These omissions make it impossible to evaluate how the intended analytic approach would have addressed several outcomes, missing follow-up or group assignment.

Finally, the safety counts show why event counts need context. Zero recorded events are not equivalent to evidence of no risk, particularly when participant numbers and follow-up completeness must be considered. The statistical lesson is not a conclusion about either procedure; it is that design, outcome completion, analysis transparency and uncertainty all determine what a trial can establish.

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 most direct limitation is that the primary endpoint was not completed. The record specifically states that 24-month post-operative ultrasound measurements could not be obtained because of early termination. Consequently, the planned primary comparison has no reported outcome data or analysis. The reason for termination is not reported in the registry record, so its implications for recruitment, follow-up or data collection cannot be assessed.

The listed enrollment is 15, but the record does not give participant flow through randomization, treatment receipt, follow-up visits or outcome assessment. It does not explain the 4 participants in the unassigned safety group, or specify how the assigned groups relate to the full enrollment for each analysis. Eligibility criteria and detailed baseline characteristics are not reported in the registry record. These gaps limit assessment of who was represented and how complete the follow-up was.

The endpoint description names a compression ratio but gives no unit, calculation details or interpretation threshold. The record does not report measurement procedures beyond ultrasound or whether assessment was conducted without knowledge of treatment assignment. The trial was not masked, and no information is given about masking of outcome assessors. Statistical methods, analysis populations, missing-data handling and multiplicity procedures are also not reported in the registry record.

Safety information is limited to group counts for serious events, other events and deaths. Event definitions, observation periods and data collection methods are not reported. These limitations mean that neither the absent primary comparison nor the zero event counts should be read as definitive evidence about differences or lack of differences between the procedures.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Prospective Randomized Controlled Trial of Obstructed Defecation Surgery — NCT05747027.
• Registry record last updated 2025-07-15; status last verified 2025-07.
• Results first posted 2025-07-15.
• 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

The PROD Trial, NCT05747027, is listed as a randomized, open-label, parallel-group study comparing laparoscopic abdominal ventral rectopexy with transvaginal sacrospinous rectopexy for obstructed defecation in pelvic organ prolapse. The registry lists enrollment as 15, a study start date of 2024-05-16, a primary completion date of 2025-05-30, and status as terminated.

The primary outcome was ultrasound-measured rectal hypermobility, described as the compression ratio, at 24 months post-operatively. The record says these measurements could not be completed because of early termination. It lists 12 outcome measures and no analyses. The safety entries report zero serious adverse events, zero other adverse events and zero deaths in each listed group, including the unassigned group. The reason for termination, statistical analysis plan, and comparative outcome results are not reported in the registry record.