Same Day Discharge After Minimally-invasive Sacrocolpopexy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Same Day Discharge After Minimally-invasive Sacrocolpopexy (NCT03730103), a non-randomized na study. The primary outcome is Number of Participants* With Serious Adverse Events.

2. Clinical Question

3. Trial Design

This is a completed, prospective cohort study listed as non-randomized, unmasked, and parallel. Its stated focus is the safety, cost, and patient satisfaction associated with same-day discharge after minimally invasive sacrocolpopexy for pelvic organ prolapse. The registry reports enrollment of 52 and lists the study dates as 2018-10-22 and 2020-06-01 for study start and primary completion.

The same-day discharge group was prospectively recruited. The comparator was historical: patients who had the same procedure and were discharged on POD 1. The record describes the historical data as coming from a prospective cohort associated with a randomized trial, but that does not make the present same-day discharge comparison randomized. Patients in the two discharge groups were not assigned by random allocation within this study.

The intervention is described as same-day discharge, supported in part by a study-specific education video and an ERAS pathway. Outcomes were to be assessed on POD 0/1 and at routine postoperative follow-up, generally at 6 weeks after surgery. The primary outcome timeframe is specifically listed as 6 weeks postoperatively. Other listed outcomes concern patient-initiated phone calls, unscheduled office visits including voiding trials, and emergency department visits.

The registry’s enrollment figure and arm descriptions do not align transparently with the primary outcome denominators. It describes a historical cohort of 60 women and 47 women recruited for same-day discharge; the serious-event groups list 61 and 47 participants at risk. The reason for the differing historical figures is not reported in the registry record. The study is marked completed, but statistical analysis results beyond the event counts are not reported.

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: Subjects were excluded: (2) case start-times after 1:00 p.m., (1) case aborted, (1) approach changed to vaginal, (1) patient withdrew.

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 Number of Participants* With Serious Adverse Events, measured over 6 weeks postoperatively.

The primary endpoint counts participants with serious adverse events during the 6 weeks after surgery. It is a participant-level count: a participant is counted as having the endpoint if they experienced a serious adverse event within the stated timeframe. The registry gives the outcome title as “Number of Participants* With Serious Adverse Events” and describes the purpose as comparing the incidence of adverse events after same-day discharge with the historical POD 1 discharge group.

A serious-event endpoint is relevant to a discharge strategy because the study is assessing safety after surgery and the timing of discharge. It focuses on events classified as serious, rather than every symptom, contact, or postoperative service use. The record separately lists patient-initiated phone calls, unscheduled office visits including voiding trials, and emergency department visits as secondary outcomes; these are distinct from the primary serious-adverse-event count.

The registry reports the primary timeframe as 6 weeks postoperatively. It does not define the event-classification rules, explain whether severity was adjudicated, or describe how recurrent events in the same participant were handled. Those details are not reported in the registry record, so the posted participant counts should be interpreted as the registry’s reported endpoint rather than as a more detailed event-level analysis.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant-level event count represent?

The primary endpoint is a count of participants who experienced serious adverse events within the stated follow-up timeframe. A participant-level endpoint is different from an event-level count: if a participant has more than one event, a participant-level count generally focuses on whether that participant met the endpoint, while an event-level count can include multiple events from the same person. The registry identifies the outcome as a count of participants, but does not explain its detailed counting rules. It is therefore best to read the posted numbers as participant counts, not as a complete tally of every serious event.

The primary timeframe is 6 weeks postoperatively. A defined follow-up period gives the endpoint a time boundary, but the record does not provide details on completeness of follow-up, event adjudication, or how events occurring after discharge were captured. The study summary says assessments were planned on POD 0/1 and at routine postoperative follow-up, generally at 6 weeks. How those assessment points relate to the final endpoint ascertainment is not reported in the registry record.

Why does the non-randomized design matter?

Random allocation can help balance measured and unmeasured participant characteristics between groups on average. Here, the comparison is explicitly non-randomized: the same-day discharge group was prospectively recruited, while the comparator was historical. As a general statistical principle, a historical comparison can be affected by differences in patient selection, care practices, calendar period, or outcome measurement. These are potential sources of bias, not claims that a particular difference occurred in this study. The registry does not report an adjustment strategy or detailed baseline comparisons that would show how such issues were handled.

The control group is described as drawn from a prospective cohort associated with a randomized trial of two types of lightweight polypropylene mesh. That description concerns the source of the historical data; it does not mean that participants were randomized to same-day versus POD 1 discharge in the present comparison. The reported allocation for this study is non-randomized, and masking is listed as none.

What can an estimate and confidence interval add?

As a general statistical concept, an effect estimate summarizes the direction and magnitude of a comparison, while a confidence interval conveys the uncertainty around that estimate under the chosen statistical method. A narrow interval indicates greater precision than a wide interval, but an interval does not remove bias from a non-randomized design. The registry record reports no comparative estimate or confidence interval for the primary endpoint, so the uncertainty around a group difference cannot be evaluated from the record’s event counts alone. No p-value is reported either.

An unadjusted recalculation from summary counts would not replace a sponsor’s own analysis if the record posted one; no sponsor analysis is reported. The counts can be described as posted, but they do not support a claim about statistical significance or a precise comparative effect. No adjusted outcome analysis, model specification, or covariate list is reported in the registry record.

What does the planning illustration mean?

The record describes planning illustrations based on the observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such calculations are hypothetical planning exercises: they indicate sample size requirements under selected assumptions, not the study’s observed power and not evidence that the effect is true. The registry does not report the protocol’s sample-size justification or its own design calculation. The planning assumptions should therefore not be mistaken for an analysis plan or for a basis to judge the trial’s actual power.

General sample-size calculations depend on the endpoint, the target effect, the variability or event frequency, the allocation scheme, and the chosen error criteria. For binary outcomes, assumptions about event rates can strongly affect a planning result. A calculation anchored to an observed effect is especially uncertain because the observed effect itself may be imprecise. The planning illustration does not resolve the uncertainty in this study’s primary comparison.

How should adverse-event terms be read?

The registry lists participant counts for serious adverse events and provides several serious-event terms with percentages. These figures are not accompanied by a detailed event-level table, group-specific term counts, or an explanation of whether a participant could contribute to more than one term. General caution is appropriate: event terms describe categories, while the primary endpoint counts participants. Without the event definitions and attribution rules, the terms should not be treated as a separate comparative analysis. The listed percentages should be quoted as recorded, not converted into counts or assigned to a group.

Overall, the posted information supports a descriptive account of the endpoint and study design. It does not supply enough statistical detail to reconstruct the sponsor’s inferential analysis, assess adjusted effects, or evaluate model assumptions. Analysis procedures, if any, are not reported in the registry record.

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("Historical Control Group", "Same Day Discharge Group")
n      <- c(61, 47)
events <- c(4, 3)
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  Historical Control Group  61  4  6.6  1.8  15.9  2.6  15.7  2.7  15.7
ARM  Same Day Discharge Group  47  3  6.4  1.3  17.5  2.2  17.2  2.3  17.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures: the primary serious-adverse-event count and secondary measures concerning patient-initiated phone calls, unscheduled office visits including voiding trials, and emergency department visits. The study description also names cost and patient satisfaction as aims, but comparative results for these aims are not reported in the registry record. A statistical plan describing which outcomes were confirmatory, how outcomes were prioritized, or whether multiplicity was addressed is not reported.

Multiplicity matters when several outcomes or comparisons are examined. As a general principle, testing many hypotheses can increase the chance of finding an apparently notable result by chance, unless the analysis plan accounts for the number and structure of tests. The registry record reports 0 analyses and does not provide p-values for the listed outcomes, so it is not possible to determine whether any adjustment was used or to interpret a family of inferential tests.

Missing-data methods and follow-up completeness are not reported in the registry record. The record does not state how missing outcome information, incomplete follow-up, or participants without ascertainable event status were handled. The analysis population is also not described: there is no reported definition of an intention-to-treat, per-protocol, or other analysis set. Because this is a non-randomized comparison, the registry also does not report how eligibility, recruitment, or inclusion in the historical group was handled analytically.

These omissions limit assessment of possible bias and the reproducibility of any comparison. They do not establish that data were missing or that multiplicity affected the findings; those matters are simply not reported in the registry record.

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 0% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: wound infection (4.3%), neurologic injury (3.3%), bowel obstruction (2.1%), cardiopulmonary (1.6%).

For the primary serious-adverse-event outcome, the registry reports 4 participants among 61 at risk in the historical control group and 3 among 47 at risk in the same-day discharge group, within 6 weeks postoperatively. The record also reports 0 deaths in each group and 0 other adverse events in each group under its adverse-event fields. These are descriptive entries, not a randomized comparison or a statement about causation.

The registry’s list of top serious terms includes wound infection at 4.3%, neurologic injury at 3.3%, bowel obstruction at 2.1%, and cardiopulmonary events at 1.6%. Those percentages are posted without group-specific attribution in the available record. They should not be interpreted as rates for the same-day discharge group or historical controls, nor should they be added together; the record does not explain whether terms can overlap or how the percentages were calculated.

There is no reported comparative test, confidence interval, or event-adjudication description. The denominators also require care: the registry describes the historical cohort as 60 women but lists 61 at risk for the serious-event outcome. That difference is not explained in the registry record. These data describe what is posted, but do not by themselves establish comparative safety.

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

The result is a descriptive record of serious adverse-event counts in two groups with different discharge histories. The registry reports 4 participants with serious adverse events among 61 at risk in the historical POD 1 group and 3 among 47 at risk in the same-day discharge group during the stated 6-week postoperative period. It also lists 0 deaths in each group. The record does not report a comparative statistical estimate, confidence interval, or p-value.

These counts do not show that discharge timing caused the observed events, or that one discharge approach is safer. The comparison was non-randomized and uses a historical control. Without random allocation or a reported adjusted analysis, observed differences may reflect factors other than discharge timing. The registry does not provide enough information about baseline characteristics, event ascertainment, or analysis methods to assess those possibilities.

The broader study aims included cost and patient satisfaction, and the registry lists additional measures of calls, office visits, and emergency department visits. Numerical comparative results for these outcomes are not reported in the registry record. The serious-event counts therefore do not summarize all the outcomes the study intended to examine.

Likewise, the absence of a reported estimate or test is not evidence that the groups were equivalent. Equivalence or non-inferiority requires a defined statistical framework and supporting estimates; neither is reported in the registry record. The event counts offer useful descriptive information, but their precision and the strength of any comparative conclusion cannot be established from the posted results alone.

14. Why This Trial Matters Statistically

This study raises an important statistical question about how to compare care pathways when random allocation is not used. Same-day discharge is compared with a historical POD 1 group, so the contrast reflects both discharge timing and any differences between the groups that may have arisen from recruitment, clinical practice, or the period in which care occurred. Statistical adjustment can sometimes address measured differences, but the registry record does not report such an approach, and adjustment cannot automatically remove unmeasured confounding.

The record also illustrates why endpoint definitions and denominators matter. The primary outcome is a participant count over a stated follow-up period, while the record separately lists terms and percentages for serious events. Those forms of reporting answer different questions. Clear definitions of who counted as at risk, how serious events were identified, and how multiple events were handled are important for interpretation, but these details are not reported in the registry record.

Precision is also central to safety comparisons. Counts without comparative intervals or tests do not show how much uncertainty surrounds a potential difference. This is particularly relevant when the aim is to compare serious events, because the endpoint is a count of participants and the study’s actual inferential method is not reported. Planning illustrations based on an observed effect do not substitute for the trial’s original sample-size rationale or an analysis of uncertainty.

Finally, the mismatch among the overall enrollment figure, the historical group description, and the outcome denominators is a reporting issue that should remain visible rather than be reconciled by assumption. Transparent accounting of participants and analysis populations is essential for evaluating how the reported endpoint arose.

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 primary limitation for interpretation is the non-randomized historical comparison. The same-day discharge group was recruited prospectively, whereas the comparator was historical. The registry does not report adjustment for differences between groups, detailed baseline characteristics, or a matching procedure sufficient to evaluate comparability. As a result, the observed counts cannot be attributed to discharge timing alone.

Reporting of participant numbers is not fully reconciled. The registry lists enrollment of 52, describes the historical cohort as 60 women, and reports 61 at risk for the historical serious-event outcome; the same-day discharge description gives 47 women and the outcome denominator is 47. The record does not explain why the historical figures differ or how the overall enrollment relates to the arm descriptions. No explanation should be assumed.

Important analysis details are not reported in the registry record, including missing-data handling, analysis populations, event definitions and adjudication, follow-up completeness, statistical methods, and any covariate adjustment. The record reports 0 analyses and does not include a comparative effect estimate, confidence interval, or p-value for the primary endpoint.

The registry identifies cost and patient satisfaction as study aims, but does not report comparative results for them. Numerical results for the listed secondary outcomes are also not reported in the registry record. Serious-event terms are listed with percentages but without group-specific attribution or a description of how those percentages were calculated. Together, these gaps constrain interpretation of both the safety comparison and the study’s broader aims.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Same Day Discharge After Minimally-invasive Sacrocolpopexy — NCT03730103.
• Registry record last updated 2020-09-25; status last verified 2020-06.
• Results first posted 2020-09-25.
• 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

The registry record describes a completed, non-randomized, unmasked, parallel prospective cohort study of same-day discharge after minimally invasive sacrocolpopexy for pelvic organ prolapse. The comparison group was historical and discharged on POD 1. The study description identifies safety, cost, and patient satisfaction as aims; the primary outcome is the number of participants with serious adverse events within 6 weeks postoperatively.

Serious adverse events were reported in 4 participants among 61 at risk in the historical control group and 3 among 47 at risk in the same-day discharge group. The record reports 0 deaths in each group. It does not report a comparative effect estimate, confidence interval, p-value, or detailed statistical analysis. The listed secondary outcomes concern patient-initiated calls, unscheduled office visits including voiding trials, and emergency department visits.

Several details remain unclear in the registry record, including the relationship among enrollment, arm-description, and outcome-denominator figures; missing-data handling; analysis populations; and event ascertainment. The reported counts are descriptive and do not establish a causal or comparative conclusion.