Utility of an Animated Bowel Biofeedback Training Routine to Improve Bowel Function in Individuals With SCI: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Utility of an Animated Bowel Biofeedback Training Routine to Improve Bowel Function in Individuals With SCI (NCT02406859), a non-randomized na study. The primary outcome is Baseline Motility (Anorectal Sensation and Strength) Characteristics.

2. Clinical Question

3. Trial Design

The registry record identifies a completed, non-randomized study with a single-group model and single masking. The study was sponsored by the VA Office of Research and Development. Its registered enrollment is 50. The listed conditions are spinal cord injury, constipation, fecal incontinence, and neurogenic bowel. The record gives a start date of 2013-07-01 and a primary completion date of 2017-06-30.

The study description has an assessment component and a biofeedback component. For the assessment, participants undergo anorectal manometry and baseline evaluation of constipation or fecal-incontinence frequency. The arm descriptions refer to 50 spinal cord injury participants and 15 able-bodied participants, and also describe an additional control group of 10 able-bodied participants. The registered enrollment figure and these arm-description details are not reconciled in the registry record, so they should not be treated as interchangeable counts.

A subgroup of spinal cord injury participants with constipation or fecal incontinence is described as eligible for biofeedback. The arm description specifies 20 participants and 12 weeks of twice-weekly training. The brief summary instead describes a subgroup receiving six weeks of twice-weekly laboratory training, and its final sentence is incomplete. This inconsistency limits what can be concluded about the intended intervention schedule.

Because allocation is non-randomized and the model is single-group, the study is not presented as a randomized comparison of biofeedback against a concurrent control. The able-bodied and spinal cord injury groups primarily provide context for baseline motility assessment. The registry record does not report the allocation procedure, adherence, participant flow, or the number completing training.

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: American Spinal Cord Injury Association (ASIA) exams were administered to all subjects with spinal cord injury to determine severity of injury and whether the participant meets the criteria to participate in bowel biofeedback training portion.

Part 1 - Manometric Parameters

Part 2 - Biofeedback Training

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.

Population: The information available was collected from participants that participated in in part 1 of the study as opposed to those participants that consented to the study. The subjects that consented but did not start part 1 are not included in this information.

6. Primary Endpoint

The registry lists the primary outcome as Baseline Motility (Anorectal Sensation and Strength) Characteristics, measured over 1 Session (Baseline Anorectal Manometry Assessment).

The primary outcome is titled baseline motility, with anorectal sensation and strength characteristics assessed in one baseline anorectal manometry session. The listed measures include maximum sphincter pressure at rest and during squeezing, mean sphincter pressure, residual anal and intrarectal pressure in the high-pressure zone, and the recto-anal pressure differential. The stated unit is mmHg, and the summary measure is the mean with standard deviation.

Anorectal manometry records pressure patterns during assessment of anorectal function. In general, pressure measures can help describe how the sphincter and rectal region respond during rest and voluntary maneuvers. The recto-anal pressure differential describes the relationship between intrarectal pressure and residual anal pressure, as specified in the study description. These are physiological measurements, rather than direct counts of bowel-care episodes or a direct measure of daily functioning.

The endpoint is explicitly a baseline characterization. It can describe motility in the groups assessed, but by itself it does not measure change caused by biofeedback. The intervention-related outcomes are listed separately as secondary outcomes, including pressure changes and changes in the recto-anal inhibitory reflex in people with incomplete spinal cord injury, and subjective bowel-care changes. Numerical estimates, group summaries, and uncertainty intervals for the primary outcome are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the primary measure as continuous, with a mean and standard deviation as the stated summary. General statistical interpretation of a continuous measure begins with the scale and the summary being reported. A mean describes the average measurement in a group, while a standard deviation describes the spread of individual measurements around that average. The registry record gives mmHg as the unit for the motility measures, but does not post the actual means or standard deviations.

What does a baseline endpoint show?

A baseline measurement describes participants at the time of assessment. It can characterize the range and average of measured pressure features in the assessed groups, but it does not quantify change after training. For a treatment effect, an analysis would ordinarily need to compare outcomes over time or compare outcomes between an intervention group and an appropriate comparator. The primary endpoint is a baseline assessment, while the listed training outcomes are secondary. Their numerical estimates are not reported in the registry record.

How should a mean and standard deviation be read?

In general, the mean is sensitive to unusually high or low observations, and the standard deviation can help indicate how heterogeneous measurements are within a group. Neither measure alone shows how precisely a group mean has been estimated; that requires information such as a standard error or confidence interval, along with the relevant analysis sample. A confidence interval, in general, gives a range of estimates compatible with the data and statistical model at a stated confidence level. No such interval is reported for the primary outcome in the registry record.

What does non-randomized allocation imply?

Randomization is a method for creating treatment groups in a way intended to reduce systematic differences at the start of a comparison. This study is identified as non-randomized and single-group. Its participant categories may be useful for describing motility across spinal cord injury status and able-bodied participants, but those groups are not described as randomized arms for estimating the effect of biofeedback. Differences between such groups could reflect baseline characteristics or other factors, not only the condition being compared. General causal interpretation therefore depends on design and analysis details beyond a simple contrast of group summaries.

For a single-group intervention assessment, a before-and-after comparison can describe change within participants. In general, such change is not automatically attributable to the intervention: natural variation, concurrent care, measurement conditions, or changes in who contributes observations can also affect the comparison. The registry record does not provide an intervention estimate or enough analysis detail to assess these issues.

Why do measurement details matter?

Anorectal manometry produces pressure measurements during specified conditions or maneuvers. The study description names resting and squeezing sphincter pressure, residual anal and intrarectal pressure, and a recto-anal pressure differential. Interpretation of such measures depends on consistent measurement procedures and clear definitions of the reported summary. The record describes a baseline session and names the measures, but does not report detailed measurement protocols, repeatability information, or numerical findings.

For repeated measurements, a statistical analysis may need to account for the fact that observations from the same participant are related. Treating related observations as independent can make uncertainty estimates misleading. General methods for repeated measures can model within-participant correlation, but the registry record does not state which analysis, if any, was used for the intervention outcomes.

What can planning calculations tell readers?

Any planning illustration based on an observed effect is not an observed trial result and is not the study’s achieved power. Such illustrations describe hypothetical future designs under stated assumptions. The record’s planning assumptions specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of an observed effect. These assumptions do not establish that the study used that design or analysis. The record does not report a sample-size justification or the study’s own statistical plan.

General power calculations depend on the effect size, outcome variability, allocation, chosen significance level, and analysis method. They are planning tools rather than evidence that an effect was present. The registry record does not report a trial-specific power calculation, a prespecified target effect, or a statistical analysis plan. No numerical treatment estimate is available in the registry record against which a reader could assess precision.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and several secondary outcomes, including pressure changes, recto-anal inhibitory reflex changes, and subjective bowel-care changes. When multiple outcomes or multiple comparisons are examined, the chance of at least one apparently unusual result can increase. General approaches to multiplicity include prespecifying a primary comparison, adjusting inferential thresholds, or clearly treating secondary analyses as exploratory. The registry record does not report a multiplicity strategy or a statistical analysis plan, so it is not possible to determine how multiple outcomes were handled.

Missing-data methods and analysis populations are also not reported in the registry record. The record does not state how many participants contributed measurements at each assessment, whether participants withdrew or missed sessions, or how incomplete outcome data were treated. It does not describe an intention-to-treat, per-protocol, or other analysis population for the intervention outcomes. These omissions matter because the participants with available measurements may differ from those without them, and analysis choices can affect both estimates and uncertainty.

The study description gives different training durations in the brief summary and biofeedback arm description. The record does not explain whether this reflects a protocol change, a difference in description, or the delivered schedule. Without a statistical plan and participant-flow information, readers cannot assess whether outcomes were analyzed as originally intended or how deviations and missing observations may have affected the results. No posted outcome analyses are available in the registry record.

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 record lists safety counts separately for able-bodied participants, participants with complete spinal cord injury, and participants with incomplete spinal cord injury. For each group, the recorded number at risk is shown alongside zero serious adverse events, zero other adverse events, and zero deaths. The record lists no serious adverse-event terms.

These entries should be read as the counts recorded in the registry, not as proof that no adverse events occurred. The record does not describe how events were defined, collected, monitored, or attributed, and it does not provide narrative safety information. It also does not explain whether all participants completed the relevant safety observation period. Zero recorded events therefore means that none are listed in these fields; it does not establish the absence of risk or exclude events that were not captured or reported.

The group counts are not a comparison of randomized treatments. The study is non-randomized, and the displayed categories are participant groups rather than intervention and control arms. These safety entries cannot establish a comparative safety effect of biofeedback.

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

The record describes a study intended to characterize anorectal motility in people with spinal cord injury and able-bodied participants, and to examine biofeedback-related outcomes in a subgroup. Its primary outcome is a baseline measure of anorectal sensation and strength characteristics, reported in concept as means with standard deviations and measured in mmHg. The record also names secondary outcomes related to pressure, reflex function, and subjective bowel care.

What the posted record does not establish is the numerical value of any primary or secondary outcome. It contains no posted analyses or outcome estimates with which to assess direction, magnitude, or precision. Accordingly, it does not show whether motility characteristics differed between participant groups, whether measurements changed after training, or how uncertain any such estimates might be.

The design information also limits causal interpretation. This is a non-randomized, single-group study, and the record does not identify a randomized comparison for biofeedback. Even if a change over time were reported, a single-group change would not by itself establish that training caused it. A causal claim would require appropriate design and analysis, with attention to other changes over time, participant selection, outcome measurement, and missing observations.

The record’s descriptions of the training duration do not agree: the brief summary refers to six weeks, while the arm description refers to 12 weeks. The record does not clarify which schedule was used. The safety entries list zero recorded serious and other adverse events and zero deaths in each group, but the available information does not establish completeness of event ascertainment.

In general, registry descriptions can explain what was planned and which measures were named, while conclusions about observed effects depend on posted results and methods. In this case, the record supports a description of the study framework and recorded event counts, but not a conclusion about biofeedback’s effect on bowel function or anorectal measurements.

13. Why This Trial Matters Statistically

This study raises a statistical distinction between describing physiology and estimating an intervention effect. Its primary measure is a baseline characterization of anorectal motility, while the biofeedback questions are listed as secondary outcomes. Keeping those purposes separate helps prevent baseline group descriptions from being mistaken for evidence of a treatment-related change.

The non-randomized, single-group structure also makes it important to distinguish association from causation. In general, a change observed after training can be informative, but without a suitable comparison it may be difficult to separate intervention-related change from other influences. Statistical methods cannot fully repair limitations in the comparison structure, and interpretation depends on transparent reporting of participant flow, measurement timing, and analysis decisions.

There is also a reporting issue relevant to reproducibility: the summary describes six weeks of training, whereas the arm description gives 12 weeks. Clear reporting of the intervention actually delivered is necessary to understand what an outcome estimate would represent. The registry record does not resolve this discrepancy.

Finally, an endpoint can be named and clinically motivated without its results being available for statistical evaluation. Here, the record identifies pressure and bowel-care outcomes but does not post numerical analyses. That absence prevents readers from assessing effect size, precision, variability, or consistency across outcomes. The study is therefore statistically informative as a description of intended measurements and design, but its registered record does not supply the evidence needed to evaluate the observed intervention results.

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 registry record does not report numerical results for the baseline motility endpoint or the listed secondary outcomes. It also reports no posted analyses. This prevents assessment of outcome distributions, group differences, within-participant changes, uncertainty, or the consistency of findings across measures.

The study is non-randomized and identified as a single-group model. The record does not describe a randomized comparator for the biofeedback component, which limits causal interpretation of any potential before-and-after change. The descriptions identify different participant categories for baseline assessment, but do not establish those categories as comparable treatment arms.

The intervention duration is inconsistent across the record: the brief summary describes six weeks, while the biofeedback arm description specifies 12 weeks. The record does not clarify which duration was implemented. The brief summary also ends mid-sentence, limiting its description of the follow-up assessment.

The registered enrollment is 50, while the arm descriptions mention spinal cord injury participants, able-bodied participants, and an additional able-bodied control group. The relationship between these descriptions is not clarified. Participant flow, completion, adherence, eligibility details, and the number contributing to each outcome are not reported in the registry record.

The record does not report the statistical analysis plan, missing-data methods, analysis populations, multiplicity handling, or a trial-specific sample-size justification. It also does not give detailed measurement procedures or repeatability information. These limitations constrain both interpretation of any future-reported estimates and replication of the study from the registry description alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Utility of an Animated Bowel Biofeedback Training Routine to Improve Bowel Function in Individuals With SCI — NCT02406859.
• Registry record last updated 2021-09-17; status last verified 2021-08.
• Results first posted 2021-09-17.
• 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

This completed, non-randomized study examined anorectal motility in people with spinal cord injury and able-bodied participants, and described biofeedback training for a subgroup with constipation or fecal incontinence. The primary outcome was baseline anorectal sensation and strength characteristics measured by manometry. Secondary outcomes concerned pressure, recto-anal inhibitory reflex, and subjective bowel-care changes.

The registry record does not report numerical outcome findings or posted analyses. It describes the biofeedback schedule inconsistently, as six weeks in the summary and 12 weeks in the arm description. Safety fields list zero recorded serious adverse events, zero other adverse events, and zero deaths in each displayed group. The record supports a description of study structure and recorded counts, but not an estimate of intervention effects.