Fecal Microbial Transplantation for the Treatment of Fecal Incontinence in Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Fecal Microbial Transplantation for the Treatment of Fecal Incontinence in Women (NCT04201821), a na phase 1, phase 2 study. The primary outcome is Number of Subjects That Show Significant Improvement at 4 Weeks After FMT, and Will be Maintained at 12 Weeks, Relative to Baseline Using the St. Mark's Vaizey Score, a Measure of Fecal Incontinence Severity..

2. Clinical Question

The study asked whether fecal microbial transplantation (FMT) was followed by a sustained improvement in fecal incontinence severity among women aged 50 years and older. It was an open-label pilot with one study group: all eligible participants were to receive FMT, with no control group described.

The registry also lists quality of life at 4 and 12 weeks and microbial engraftment with clinical improvement as secondary outcomes. These outcomes broaden the questions beyond symptom severity, but their results are not reported in the registry record. With no control group, any change over time would describe participants’ observed course after treatment; the design by itself cannot separate treatment effects from other explanations for change.

3. Trial Design

NCT04201821 is a phase 1 and phase 2 study sponsored by the University of Pennsylvania. The registry classifies it as a single-group study with no masking. Allocation is recorded as not applicable, consistent with the absence of a randomized comparison. The study is described as an open-label pilot assessing FMT for fecal incontinence in women aged 50 years and older.

The intervention was fecal microbial transplantation, classified as a biological intervention. The single arm is titled FMT Administration, and the arm description states that all eligible participants would receive FMT. A control arm, placebo, or alternative treatment is not described. The registry lists enrollment as 10. It does not report how many participants completed follow-up or were included in the primary outcome analysis.

The study start date is 2021-01-14, and the primary completion date is 2023-01-18. Its status is terminated. The reason for termination and whether the planned enrollment or follow-up was completed are not reported in the registry record. The stated primary outcome timeframe is 84 days.

The primary outcome is a participant count based on improvement in fecal incontinence severity, assessed with the St. Mark’s Vaizey Score. Secondary outcomes include the number of subjects with improved quality of life on the FIQL Scale at 4 and 12 weeks, and the count showing microbial engraftment after FMT alongside clinical improvement. The registry lists five outcome measures in total, but only the named outcomes are described in the record summarized by these details.

There are no analysis results listed in the registry record. The record does not describe a statistical analysis plan, including how outcomes would be handled if participants missed assessments. It also does not specify a comparison group or a method for estimating a treatment effect against an external standard. These omissions limit how much can be concluded from the design description alone.

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: 10 Subjects were enrolled. 2 subjects dropped out prior to administration of the investigational product. 8 subjects were treated with the investigational product.

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 Subjects That Show Significant Improvement at 4 Weeks After FMT, and Will be Maintained at 12 Weeks, Relative to Baseline Using the St. Mark's Vaizey Score, a Measure of Fecal Incontinence Severity., measured over 84 days.

The primary endpoint counts participants who meet the study’s definition of significant improvement after FMT. Improvement is assessed using the St. Mark’s Vaizey Score, described in the registry as a validated patient-reported instrument for measuring fecal incontinence severity. Its score ranges from 0-24, with a decrease representing improvement. The registry defines clinical improvement as a sustained decrease of 4-5 points between the 4-week and 12-week measurements. The endpoint title frames the assessment as improvement at 4 weeks that is maintained at 12 weeks relative to baseline; the timeframe is 84 days.

A participant count makes the endpoint clinically interpretable as the number meeting a prespecified improvement definition, rather than the average score change across the group. It also reduces a repeated score history to a yes-or-no classification for each participant. That can be useful when the question is whether participants reached a threshold considered meaningful by the study. However, the count does not show the size of each participant’s score change or the distribution of scores. The registry does not report the observed count, the number assessed at each time point, or an uncertainty interval, so the endpoint’s result and precision cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with identifying the unit being counted and the event definition. The primary endpoint is a count of participants meeting a clinical improvement rule. Each participant is classified according to whether the stated sustained decrease in St. Mark’s Vaizey Score is achieved at the specified assessments. A count is different from a mean score change: it answers how many meet the criterion, but does not describe the magnitude of change for each person or the full score distribution. The registry does not report the resulting count or the number assessed, so a rate or uncertainty estimate cannot be reconstructed.

What does a single-group design estimate?

In a single-group study, repeated measurements can describe how outcomes change over time among participants who receive the intervention. A baseline comparison is not the same as a randomized treatment contrast. Without a concurrent comparator, changes may also reflect natural variation, events occurring during follow-up, participants’ expectations, or how measurements are collected. These are general limitations of uncontrolled before-and-after comparisons; they do not show that any one explanation occurred in this study.

Open-label status means masking is not reported and the registry explicitly records no masking. In general, knowledge of treatment assignment can affect participant reports, follow-up behavior, or outcome assessment. This is especially relevant when an endpoint relies on patient-reported severity. The registry describes the St. Mark’s Vaizey Score as patient-reported, but does not describe whether other safeguards were used during data collection or assessment.

What does a confidence interval communicate?

In general, a confidence interval expresses the statistical precision of an estimate under the assumptions of the method used. A narrow interval indicates greater precision than a wide interval, while neither interval removes limitations in the study design or measurement process. The registry record does not report a confidence interval for the primary endpoint, and no interval should be inferred from the enrollment entry alone. The relevant analysis denominator and observed endpoint count are also not reported.

For a binary participant endpoint, an analysis might report a count and the proportion meeting the criterion, together with an interval estimating uncertainty in that proportion. Such an interval depends on both the observed number meeting the criterion and the number with evaluable outcome data. Neither is reported for the primary outcome. The registry gives a participant count as the endpoint type, but does not state an inferential method or whether the outcome was intended to be analyzed as a proportion, a count alone, or in another way.

What can sample-size planning show?

Sample-size planning asks how much information a proposed study might need to detect a specified effect under stated assumptions. The registry’s planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of the observed effect. Those assumptions describe a planning illustration, not the design actually recorded for this trial, which has one group and no randomized comparison. No numeric sample-size outputs are reported in the registry record.

Planning calculations do not reveal whether an observed result is statistically significant, and they are not observed power. In general, power is a design quantity tied to assumptions about an effect, variability, sample size, and analysis. A post hoc calculation based on an observed effect cannot establish the reliability of that effect. The assumptions in a hypothetical two-arm illustration should not be read as the study’s own protocol or as evidence that the trial enrolled enough participants for its primary outcome.

How should the outcome definition be understood?

The score has a stated range of 0-24, and lower scores represent improvement. The endpoint uses a threshold-based definition, requiring a sustained decrease of 4-5 points between the 4-week and 12-week measurements. Thresholds can make an endpoint easier to interpret as a count of participants who reach a specified level of change. They also discard information: a participant just below the criterion and one with no change may both be classified as not meeting it, even though their score trajectories differ. The record does not provide individual scores or the number crossing the threshold.

The specified timeframe is 84 days, while the description also identifies 4-week and 12-week measurements. The registry does not explain how missing measurements, deviations from visit timing, or participants without both follow-up measurements would affect endpoint classification. These details matter because a sustained-change endpoint requires information across more than one assessment. Without a stated analysis rule, the handling of incomplete measurement sequences cannot be inferred.

Why does over-dispersion need context?

Over-dispersion is a general issue for count models when observed counts vary more than a chosen model expects. It can make standard errors too small if the model assumes less variability than the data contain. It is not possible to say whether over-dispersion is relevant to this analysis because no count model, model assumptions, or outcome data are reported. The primary endpoint is described as a participant count, but the record does not identify a count regression or any other model. A binary classification of each participant is also distinct from modeling a number of events per participant.

Finally, the record lists no analysis entries. It does not report hypothesis tests, adjustment for baseline values, confidence intervals, missing-data methods, or an analysis population. General statistical concepts can explain what such methods would address, but they cannot fill in the study’s unreported methods. Interpretation should therefore remain at the level of the design, endpoint definition, and posted safety counts.

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("FMT Administration")
n      <- c(8)
events <- c(0)
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  FMT Administration  8  0  0.0  0.0  36.9  0.0  32.4  0.3  33.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures, including the primary severity endpoint and secondary outcomes concerning quality of life and microbial engraftment with clinical improvement. It does not report whether the investigators specified a hierarchy among outcomes, adjusted for multiple comparisons, or treated secondary analyses as exploratory. No analysis entries are listed. The approach to multiplicity is therefore not reported in the registry record.

In general, testing multiple outcomes can increase the chance of finding an apparently notable result by chance when each is assessed separately. An analysis plan may address this through a prespecified hierarchy or an adjustment procedure, but the record does not identify any such approach. There are no outcome test results available to assess in light of multiplicity.

Missing-data handling is also not reported. The primary endpoint requires baseline information and follow-up measurements at 4 and 12 weeks, yet the record does not state how participants missing one or more assessments would be classified or analyzed. It does not describe imputation, sensitivity analyses, or rules for excluding incomplete records.

The analysis population is not described. The registry does not state whether the primary analysis was intended to include all enrolled participants, only those who received FMT, or only those with complete measurements. Enrollment is listed as 10, while safety counts use 8 participants at risk; the record does not explain the relationship between these entries. Without outcome denominators and a stated analysis population, completeness and potential selection in the reported outcome data cannot be assessed.

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.

Most frequent non-serious adverse event terms

The registry reports safety figures for the FMT Administration group. Eight participants are listed as at risk for serious adverse events, and zero are listed as affected. For other adverse events, eight are listed as at risk and six as affected. Deaths are recorded as zero. These are posted counts, not estimates of comparative risk, because the study has no control group.

The serious adverse event term list is empty. This should be read alongside the reported count of zero serious adverse events; the record does not provide event descriptions or additional detail about surveillance and classification. The six affected by other adverse events are a count, and the registry does not describe the event types, severity, duration, or whether individuals experienced more than one event.

The safety denominator is 8, whereas registry enrollment is 10. The record does not explain the difference, so the safety figures should not be interpreted as applying to all enrolled participants. The counts also do not establish whether events were caused by FMT. Without a comparator and detailed event information, these figures describe what the registry reports for the group but do not quantify excess risk or establish a causal relationship.

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

The record establishes that investigators planned an open-label pilot of FMT for fecal incontinence in women aged 50 years and older, with one intervention group and a threshold-based primary outcome. It specifies the St. Mark’s Vaizey Score, the direction of improvement, and the follow-up timeframe. It also reports safety counts for the FMT Administration group. These registry entries describe the study structure and the outcomes the registry intended to track.

The record does not report how many participants met the primary improvement definition. It does not provide outcome data for the quality-of-life or microbial-engraftment measures, nor does it provide an estimate of the size or precision of any observed change. The absence of these results means the registry record cannot establish the primary outcome’s observed frequency or support a statistical comparison.

Even if a change from baseline were reported, the single-group design would not show how outcomes would have changed without FMT. It would describe participants’ observed changes, while other explanations would remain possible. The open-label design and patient-reported primary measure are additional considerations when interpreting changes, though the record does not show whether either affected the results.

The safety figures report zero serious adverse events, six affected participants for other adverse events, and zero deaths among the stated safety group. They do not establish causation or allow comparison with another treatment. The registry’s terminated status also does not explain why the study ended or whether follow-up was complete.

Accordingly, the findings available in the registry support a careful account of the trial’s aims, definitions, and posted safety counts, but not a conclusion about efficacy or a comparative safety profile. A defined endpoint, planned study, or safety count should not be mistaken for a complete analysis of clinical outcomes.

14. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the distinction between a clearly defined outcome and a reported result. The registry specifies a patient-reported severity instrument, a score direction, a clinical improvement threshold, and follow-up at 4 and 12 weeks. Those details make the intended endpoint understandable. Yet without the observed count and its denominator, readers cannot estimate how often participants met the definition or how precisely that frequency was measured.

The single-group structure also shapes the question that the data could answer. Repeated measurements can describe change within participants, but they do not supply the counterfactual comparison needed to isolate what would have happened without the intervention. This limitation is not repaired by a statistically precise estimate of within-group change; precision and causal interpretation are different issues.

The difference between enrollment and the safety denominator highlights why denominators must accompany outcome counts. The registry lists enrollment as 10 and safety information for 8 at risk, without explaining the relationship. For the primary outcome, the number assessed is not reported. Readers therefore cannot assume every enrolled participant contributed to every analysis.

The record also illustrates why planning calculations must be interpreted in context. A hypothetical calculation based on equal allocation across two arms does not describe the design of a one-group trial. Planning illustrations are not evidence about the observed result, and they are not observed power.

Finally, the terminated status is a record-level fact, not an explanation. Without the reason for termination or reported outcome analyses, the statistical account must distinguish what the registry defines from what it actually documents as observed. That distinction helps prevent a study’s intended questions from being confused with answers.

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.

Several limitations are specific to the information recorded for this trial. The study is single-group and open label, with no concurrent comparator. As a result, any reported baseline-to-follow-up change would not by itself distinguish the intervention’s contribution from other causes of change. The primary measure is patient-reported, and masking is recorded as none; the record does not describe measures to reduce expectation or assessment effects.

The registry status is terminated, but the reason for termination is not reported in the registry record. Enrollment is listed as 10, while the safety group lists 8 participants at risk. The record does not explain this difference or state how many participants completed primary outcome assessments. It also does not report the number meeting the improvement threshold, individual score changes, or uncertainty around the primary result.

The primary outcome depends on measurements at baseline and follow-up, including the stated 4-week and 12-week assessments. The registry does not report how incomplete follow-up, missed visits, or deviations in measurement timing were handled. Analysis populations and missing-data methods are not described, and no statistical analysis entries are listed.

The registry lists five outcome measures, but the approach to multiple outcomes is not reported. The secondary outcomes are named, yet their results are not reported in the registry record. The safety entries provide counts but not event descriptions, timing, severity, or attribution. These limitations constrain both outcome interpretation and the assessment of precision or generalizability.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Fecal Microbial Transplantation for the Treatment of Fecal Incontinence in Women — NCT04201821.
• Registry record last updated 2024-06-12; status last verified 2024-06.
• Results first posted 2024-06-12.
• 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

NCT04201821 is a phase 1 and phase 2, open-label, single-group pilot of fecal microbial transplantation for fecal incontinence in women aged 50 years and older. The registry lists the University of Pennsylvania as sponsor, enrollment of 10, a start date of 2021-01-14, a primary completion date of 2023-01-18, and status as terminated.

The primary endpoint is the number of participants with a sustained improvement in St. Mark’s Vaizey Score at 4 and 12 weeks relative to baseline, with a stated timeframe of 84 days. The registry record does not report the primary outcome result or analysis entries. Safety counts list 8 participants at risk, zero with serious adverse events, 6 affected by other adverse events, and zero deaths.