Feasibility of an Automated Bidet Intervention to Decrease Caregiver Burden: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Feasibility of an Automated Bidet Intervention to Decrease Caregiver Burden (NCT04283123), a randomized na study. The primary outcome is Number of Participants Recruited.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group feasibility study with no masking reported. The registry record lists an enrollment of 10 and identifies caregiver burnout as the condition. Washington University School of Medicine is listed as the sponsor. The study began on 2016-12-01, had a primary completion date of 2017-06-30, and is marked completed.

Participants were assigned to a treatment group or a waitlist control group. The treatment group was offered an automated bidet and occupational therapy over 2-3 in-home visits. Caregivers in the waitlist control group waited for 30 days and were then offered the intervention. The record does not describe other aspects of how the intervention was delivered or how adherence was assessed.

The primary outcome was the number of participants recruited, with a timeframe of 5 months. Its description states that recruiting 10 eligible caregivers was used with other variables to assess feasibility. The posted outcome lists 5 participants in the treatment group and 5 in the waitlist control group. These recruitment figures address the feasibility question as recorded; they do not establish effects on caregiver burden or other clinical outcomes.

The registry record lists 10 outcome measures and six analyses, but does not report secondary outcome results. Further details about the randomization procedure, allocation concealment, or the statistical analysis plan 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.

Before assignment: We contacted 55 informal caregivers from December 2016 to April 2017. Twenty-four(43.6%) expressed interest in participating, but 14 were ineligible (7 did not provide toileting assistance; 3 primarily used a commode or absorbent underwear; 2 had paid caregivers; 1did not meet the age criterion; and 1 care recipient was interested, but the caregiver was not). Ten informal caregivers were enrolled in this study.

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 Recruited, measured over 5 months.

The primary endpoint is the number of participants recruited. Its unit is participants, and its stated timeframe is 5 months. The registry description frames recruitment of 10 eligible caregivers as one of the variables used to assess whether the study was feasible. This makes the outcome a measure of the ability to recruit the intended study population, rather than a measure of change in caregiver burden, toileting assistance, or acceptability.

The posted outcome records 5 participants in the treatment group and 5 in the waitlist control group. Those arm-level counts describe recruitment into the randomized groups. The endpoint does not, by itself, show whether participants found the bidet acceptable, whether caregiving tasks changed, or whether any clinical outcome differed between groups.

Recruitment is useful in feasibility work because it indicates whether a study can enroll eligible participants under its study procedures. It is an operational measure, not a treatment-effect measure. The record says recruitment was considered alongside other variables, but does not identify those other variables in the primary outcome description or report results for secondary outcomes. The threshold or decision rule used to judge overall feasibility is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, parallel-group study with no masking. Randomization assigns participants to study groups by chance, which is intended to support a fair comparison when outcomes are analyzed. A parallel-group design means the assigned groups are followed as separate groups. These design features do not, on their own, specify how the random sequence was generated, how assignments were concealed, or how outcomes were analyzed. Those details are not reported in the registry record.

What kind of outcome was recorded?

The primary endpoint is a count of participants recruited, with a stated timeframe of 5 months. Although the endpoint is recorded as a count, the analysis information classifies the outcome as binary and describes its meaning as participants with an event. For a binary outcome, each participant is classified according to whether the event occurred. A count then reports how many participants met that definition. Here the primary outcome description focuses on recruitment, rather than reporting a clinical event for each participant.

The posted values are 5 participants in the treatment arm and 5 in the waitlist control arm. They are descriptive arm-level counts. A count alone does not convey the probability of recruitment without a clearly defined denominator and analysis population. The registry record does not report a separate denominator for this endpoint, recruitment over time, or a comparison estimate. No proportion, ratio, or difference should be inferred from the reported counts.

What would a comparison estimate mean?

In a randomized trial, a comparison estimate can describe how outcomes differ between assigned groups. Its interpretation depends on the outcome definition, analysis population, and statistical method. For a binary outcome, an analysis might estimate a difference in event probabilities or another contrast, but the choice of measure needs to be specified and its uncertainty assessed. The registry record states that values are missing or not estimable for a two-arm comparison of this binary endpoint. Therefore, no such effect estimate or confidence interval is available to interpret.

A confidence interval is a range of values compatible with the observed data under a specified statistical model and procedure. It conveys uncertainty around an estimate; it is not a guarantee that the true value lies within that particular interval. Since no comparison interval is reported for this endpoint, its precision as a between-group contrast cannot be assessed from the registry record. A p-value would address a different question about data compatibility under a null model, and would not describe the size or practical importance of an effect. No p-value for this comparison is reported.

What can be said about planning calculations?

The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. For time-to-event calculations, the assumptions describe total events; for other outcomes, they describe participants per arm. These are planning assumptions, not results from the trial. Since the registry record indicates that a two-arm comparison is not estimable for this endpoint, no planning sample-size result based on an observed comparison is available to interpret. Any sample-size illustration would be a planning calculation, not observed power and not evidence that the study did or did not have adequate power.

Over-dispersion is relevant to outcomes where the observed variability exceeds what a chosen statistical model expects. Accounting for it can prevent uncertainty from being understated. The posted primary outcome is a recruitment count, and the registry record gives no dispersion estimate or model-based comparison for it. There is therefore no basis in the record to assess over-dispersion for a treatment-effect analysis. More generally, selecting an analysis model requires information about the outcome definition and data structure, not simply the label attached to the endpoint.

What analysis details are absent?

The registry record does not report the statistical analysis plan, the randomization method, a comparison model, covariate adjustments, or a confidence interval for the primary outcome. It also does not report how missing outcome data were handled, define an analysis population, or state whether an intention-to-treat approach was used. The registry lists six analyses, but that count does not identify which methods were applied to the primary endpoint. No recalculated estimate is presented because the information needed for a two-arm calculation is not estimable in the posted 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("Treatment", "Waitlist Control")
n      <- c(5, 5)
events <- c(5, 5)
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  Treatment  5  5  100.0  47.8  100.0  56.6  100.0  54.1  99.6
ARM  Waitlist Control  5  5  100.0  47.8  100.0  56.6  100.0  54.1  99.6

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 10 outcome measures and six analyses, but no secondary outcome results are reported. It does not identify which outcomes were treated as primary or secondary beyond the posted recruitment endpoint, or explain how the analyses relate to the outcome measures. A multiplicity plan describing how to account for testing several outcomes or comparisons is not reported in the registry record. Without that information and the relevant results, the chance of false-positive findings across analyses cannot be assessed.

The primary recruitment outcome is posted by randomized group, but the registry does not describe missing-data handling for this or other outcomes. It does not state whether all randomized participants were included in each analysis, how participants with incomplete follow-up were treated, or whether an intention-to-treat analysis was used. The analysis populations and any exclusions are not reported in the registry record.

These omissions matter because outcome availability and analysis populations can affect interpretation, especially when a study reports multiple outcomes. The available recruitment counts do not establish how missingness or exclusions were handled for other measures. It is not appropriate to assume that all outcome data were complete or that a particular analysis population was used.

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.

The registry lists 0 serious adverse events among 5 participants at risk in the treatment group, and 0 among 5 participants at risk in the waitlist control group. It also lists 0 other adverse events in each group and 0 deaths in each group. No serious adverse-event terms are listed.

These are the safety counts recorded in the registry. A count of 0 means that no events of that category were recorded in the corresponding group; it does not show that the risk of an event is absent. With a limited number of participants at risk, the data cannot precisely characterize uncommon harms. The registry record does not provide additional information about adverse-event collection, event definitions, observation time for safety, or whether all events were actively assessed.

The waitlist group was offered the intervention after 30 days, but the adverse-event record does not explain how that timing relates to safety follow-up. These figures should be interpreted as descriptive counts, not as a definitive safety comparison between groups.

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

The posted results support a narrow conclusion: the registry records recruitment counts of 5 participants in each randomized group for a feasibility study whose primary outcome was the number recruited within 5 months. The study description identifies recruiting 10 eligible caregivers as a feasibility measure. These data speak to recruitment as recorded, not to the effect of the intervention on caregiver burden.

The study evaluated the feasibility of an automated bidet intervention, including acceptability and preliminary efficacy, according to its brief summary. However, the posted primary outcome is recruitment. Secondary outcome results are not reported in the registry record, so the available results do not establish whether the intervention was acceptable or whether caregiving or toileting outcomes changed.

The absence of an estimable two-arm comparison also means that the recruitment counts do not provide a statistical estimate of a treatment-versus-control effect. No confidence interval or p-value for such a comparison is reported. This is not evidence that the groups were equivalent; it means that the registry does not provide an estimable comparison for this outcome.

The safety record lists no serious adverse events, other adverse events, or deaths in either group. Those counts describe what was recorded in this study, but do not establish that such events cannot occur. The registry does not provide enough detail about safety ascertainment to extend the interpretation beyond the posted counts.

Overall, the record is best read as reporting recruitment and safety counts from a completed randomized feasibility study. It does not provide the clinical outcome results or analysis details needed to draw conclusions about changes in caregiver burden or the intervention’s effect on care. The threshold for judging overall feasibility, beyond the recruitment measure described, is not reported in the registry record.

14. Why This Trial Matters Statistically

Feasibility studies address whether the practical elements of a larger research effort can be carried out. Recruitment is a particularly direct operational measure: a study needs to reach and enroll eligible participants before it can evaluate its intervention with adequate outcome data. In this trial, the registry identifies recruitment of 10 eligible caregivers within 5 months as one feasibility measure and reports the arm-level recruitment counts.

Statistically, it is important to distinguish that operational question from a comparative treatment question. The presence of randomized groups does not make every posted outcome a treatment-effect endpoint. Recruitment counts can describe enrollment, while a clinical comparison requires an outcome defined to capture a participant-level consequence of treatment and an analysis that estimates the between-group contrast with uncertainty. The registry does not report an estimable comparison for the primary recruitment endpoint.

The distinction also guards against overinterpreting a small feasibility record. Counts can be informative about study conduct without establishing a clinical benefit or lack of benefit. In addition, feasibility may depend on multiple factors, but the registry’s primary outcome description does not specify the full set of criteria or how they would be combined. The results for other outcome measures are not reported.

For biostatisticians and clinical researchers, the record illustrates why endpoint labels, estimands, denominators, and analysis plans matter. A recruitment count is meaningful in its stated context, but it cannot substitute for results on burden, acceptability, or other outcomes. Clear reporting of participant flow, missing data, outcome definitions, and statistical methods would allow readers to assess feasibility more fully and to distinguish descriptive findings from inferential claims.

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 endpoint captures recruitment, not a direct clinical outcome. Although the brief summary refers to acceptability and preliminary efficacy, secondary outcome results are not reported in the registry record. This limits interpretation to the posted recruitment and safety counts and prevents assessment of whether the intervention affected caregiver burden or toileting assistance.

The registry record does not report a two-arm comparison estimate for the primary outcome, nor a confidence interval or p-value. It also does not provide the statistical analysis plan, analysis population, missing-data approach, or details of the randomization procedure. These omissions limit assessment of the methods underlying the posted results.

The primary outcome description identifies recruitment of 10 eligible caregivers within 5 months as a feasibility measure, but the decision rule for success is not reported. The record also says recruitment was used with other variables to assess feasibility without specifying those variables in the primary outcome description or reporting their results. Thus, the posted recruitment counts alone cannot characterize overall feasibility.

Safety interpretation is limited by the absence of further information about adverse-event definitions, collection, and follow-up. The counts are descriptive and cannot establish the absence of risk. The record does not provide further eligibility details or a fuller account of the caregiver and care-recipient context, which also limits judgments about how broadly the findings might apply.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Feasibility of an Automated Bidet Intervention to Decrease Caregiver Burden — NCT04283123.
• Registry record last updated 2026-11-04; status last verified 2026-11.
• Results first posted 2024-11-20.
• 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

NCT04283123 is a completed randomized, parallel-group feasibility study sponsored by Washington University School of Medicine. The registry lists no masking and an enrollment of 10. The study began on 2016-12-01, with primary completion on 2017-06-30.

The intervention arm was offered an automated bidet and occupational therapy over 2-3 in-home visits. The waitlist control group waited for 30 days and was then offered the intervention. The primary outcome was the number of participants recruited within 5 months, with recruitment of 10 eligible caregivers identified as a feasibility measure. The posted outcome lists 5 participants in each group. A two-arm comparison is not estimable in the registry record.

The record lists 10 outcome measures and six analyses, but no secondary outcome results. It reports 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. Further statistical, missing-data, and safety-assessment details are not reported in the registry record.