Foot Neuromodulation for Nocturnal Enuresis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Foot Neuromodulation for Nocturnal Enuresis (NCT02315560), a na na study. The primary outcome is Decrease in Nocturnal Enuresis.

2. Clinical Question

The study’s stated aim was to determine the effects of electrical stimulation of nerves in the foot on the incidence of nocturnal enuresis in children. The outcome description specifies a daily night-time voiding log as the measure of bedwetting and defines response by a reduction in wet nights. This is a within-participant question: it asks whether participants met the stated improvement criterion during the stimulation period, not whether stimulation performed better than another treatment or a control condition.

The record also lists Quality of Life Questionnaire Scores as a secondary outcome. It does not provide the scores or an analysis of that measure. More generally, the clinical question can be identified from the study aim and outcome definition, but the posted record does not show the results needed to assess how many participants met the response criterion or how uncertain that estimate is.

3. Trial Design

The registry record describes a completed, single-group study of foot stimulation for nocturnal enuresis in children. Enrollment is listed as 25. The study began in 2014-09 and has a primary completion date of 2017-04-06. The record lists phase as NA, allocation as NA, and masking as NONE. It does not describe a randomized comparison or a separate control group; the listed arm is Tibial Nerve Stimulation.

The intervention is identified as a transcutaneous electrical nerve stimulator, and the brief summary describes electrical stimulation of nerves in the foot. The arm description says that participants or their parents would record a night-time voiding log for a two week period before foot stimulation. It then describes recording the number of incontinent episodes per night. The available description ends before completing its account of what the baseline log was intended to determine, so further details should not be inferred from it.

The primary outcome is framed around a 6-week stimulation period. It counts participants with a clinical response, with response defined as improvement of at least 1 wet night reduction. The record lists two outcome measures and identifies Quality of Life Questionnaire Scores as a secondary outcome. It reports zero analyses in the posted results record, and no primary outcome result is shown there.

This design can describe the recorded experience of participants in the stimulation group, but it cannot directly estimate a treatment-versus-control contrast. Without a distinct comparison group, changes over time cannot be separated from other explanations by a between-group comparison. The record does not report details of the stimulation schedule, adherence, eligibility criteria, analysis population, or a statistical analysis plan.

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

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 Decrease in Nocturnal Enuresis, measured over 6 weeks.

The primary endpoint is the count of participants who had a clinical response during the 6-week stimulation period. The registry record defines a response as improvement of at least 1 wet night reduction and says that the outcome is measured using a daily night-time voiding log. The endpoint therefore turns the log information into a participant-level classification: whether each participant met the stated response criterion.

A response count can make a study outcome readily interpretable by expressing how many participants met a prespecified clinical criterion. It is different from reporting each participant’s night-by-night pattern, the average number of wet nights, or the size of change in the whole group. Those other summaries are not described as the primary endpoint in this record.

The endpoint is intended to address whether participants experienced the stated improvement during the stimulation period. However, the registry record does not post the observed response count, the number included in the endpoint analysis, or an estimate of uncertainty. It is therefore possible to explain what the endpoint was designed to measure, but not to describe the observed response rate or the precision of an estimate based on it.

The record’s description also leaves practical measurement details unreported, including how incomplete logs were handled and how a participant’s response was determined when log information was missing. Those details matter because the endpoint depends on recorded nights and a threshold-based definition of improvement.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record gives the study’s design labels and outcome definition, but it does not report a detailed statistical methods plan. The methods discussion therefore distinguishes what is described in the record from general statistical context. The record lists a single-group design, allocation as NA, and masking as NONE. It does not describe a randomized control comparison, a prespecified statistical model, a hypothesis test, an interim analysis, or a sample-size justification.

What does a single-group design estimate?

In general, a single-group study can summarize outcomes observed among the participants assessed. For a binary endpoint such as the response definition in this study, a basic summary could state how many participants met the criterion and how many were assessed. A confidence interval, in general, can show the range of values reasonably compatible with the data under the assumptions of the method. It describes uncertainty in an estimate; it does not remove design limitations or establish a causal effect.

Here, the registry record identifies a participant count as the outcome, but it does not post the responder count, analysis denominator, or interval. It is not possible to reconstruct these from the enrollment field or the safety section. The primary outcome’s participant-level response definition also means that its analysis would depend on classifying each participant using the night-time log. No classification results are posted.

Why is there no treatment contrast?

In general, a comparison group gives a study a direct way to compare outcomes under different conditions. In a single-group study, a before-and-after description may show that recorded outcomes changed over time, but it cannot by itself separate the intervention from other possible explanations for that change. The registry record does not specify a comparative analysis, and the listed design has no separate comparator arm. Accordingly, a treatment-versus-control effect estimate is not available from the posted record.

The arm description mentions a night-time voiding log for a two week period before foot stimulation. A pre-stimulation record can provide context for the outcome period, but the registry record does not provide the baseline log results or a statistical plan for comparing baseline and stimulation periods. It also does not complete the sentence describing what the baseline log was intended to determine. No additional protocol detail should be inferred from that partial description.

What can a confidence interval convey?

As a general statistical concept, a confidence interval expresses the precision of an estimate under a specified method and its assumptions. A narrower interval indicates more precision than a wider interval, while the interval’s location indicates the values compatible with the observed data under that method. An interval does not guarantee that the estimate is free of bias, and it cannot compensate for the lack of a comparison group. No confidence interval for the primary endpoint is reported in the registry record.

What do the sample-size illustrations mean?

The sample-size section is described as a planning illustration computed from the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also describes planning for a stated fraction of the observed effect. These are assumptions for an illustrative future comparison, not a description of this study’s single-group design. The registry record does not report that these assumptions were used to design the trial.

In general, a sample-size calculation asks how many participants a hypothetical study would need under specified assumptions about the effect, variability, design, and statistical error rates. Its output is conditional on those assumptions. It is not a measure of the probability that the observed study result is correct, and it is not observed power. Because the primary result is not posted, the sample-size illustration should not be read as evidence about the clinical outcome.

The illustration’s stated equal-allocation assumption and two-arm framing also differ from the design recorded for this study. The calculation may be useful as a planning scenario, but it does not turn this study into a comparative trial and does not provide a missing control-group result. The calculated tables and plots can display calculated summaries, but they cannot recover an outcome analysis that is absent from the registry record.

Why can over-dispersion matter?

In general, over-dispersion occurs when the observed variability in data is greater than a statistical model expects. For count outcomes, extra variability can make standard errors too small if a model fails to account for it, which can make uncertainty appear lower than it is. This study’s primary endpoint, however, is described as a count of participants with a binary response, not as a reported model for repeated nightly counts. The record does not report an over-dispersion assessment or a model for the nightly log data, so no claim about such an assessment can be made.

Repeated observations can also raise general analytic questions about how to account for measurements from the same participant, since nights from one person are not necessarily independent observations. The registry record does not report an analysis of nightly measurements or specify a model for repeated data. The primary endpoint’s stated participant-level response may have been intended to summarize the log data, but the record does not explain the derivation beyond its response definition.

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("Foot Stimulation")
n      <- c(22)
events <- c(16)
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  Foot Stimulation  22  16  72.7  49.8  89.3  51.8  86.8  51.6  86.8

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists two outcome measures: the primary measure of response in nocturnal enuresis and the secondary measure of Quality of Life Questionnaire Scores. It reports zero analyses and does not post results for either measure. The record does not describe a plan for controlling multiplicity, such as how interpretation would account for examining more than one outcome, or how multiple analyses of an outcome would be handled. It would be inappropriate to infer such a plan from the list of outcomes alone.

Missing-data methods are also not reported in the registry record. The primary endpoint depends on a daily night-time voiding log, and the arm description mentions a pre-stimulation log for a two week period. The record does not explain what happened when logs were incomplete, how missing nights were treated, or whether participants without adequate records were included in the endpoint analysis. It also does not report the number of participants with usable primary outcome data.

The enrollment field lists 25, while the serious adverse event section lists 22 at risk. The registry record does not explain these counts or identify an analysis population for the primary outcome. The safety denominator cannot be used as a substitute for the efficacy denominator. The record also does not report whether the primary analysis included all enrolled participants, only participants who started stimulation, or another defined group.

These omissions limit interpretation independently of the absence of outcome estimates. In general, missing observations and choices about analysis populations can affect both the estimate and its uncertainty. Without a reported plan and participant flow, readers cannot assess how these issues were addressed for this study.

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 record lists a Foot Stimulation serious adverse event group with 22 participants at risk and zero serious events. It also lists zero deaths and no serious adverse event terms. These are the posted serious adverse event figures for that group.

“At risk” is the denominator used in this safety summary. It is not necessarily the number enrolled or the number contributing data to the primary endpoint; the record does not explain the difference between the enrollment figure of 25 and the safety figure of 22. The safety denominator should therefore be read as part of the serious adverse event summary, not as evidence about the primary outcome population.

In general, a count of zero means that no events in the specified category were recorded in the summarized group. It does not establish that no adverse events of any kind occurred, because this entry concerns serious adverse events and the record does not provide a broader adverse-event summary. Nor does a zero count prove that an event is impossible. The record’s safety figures should be interpreted as a description of the posted data, not as a complete characterization of all possible harms.

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

This registry record identifies a completed study that asked whether foot stimulation could be associated with improvement in nocturnal enuresis among children. It specifies a participant-level primary endpoint and a 6-week stimulation period. Those details make the intended clinical question understandable, but the record does not post the primary outcome result. It therefore does not show how many participants met the response criterion or how precisely that outcome was estimated.

The record also does not provide a separate comparison group. Even if a within-group change had been reported, the design would not directly compare that change with what would have occurred under another condition. A single-group observation can describe participants’ recorded outcomes, but it cannot by itself establish that the intervention caused a change. In this case, the absence of a posted outcome analysis means even that descriptive assessment cannot be made from the registry record.

The result does not mean that the intervention was effective or ineffective; those conclusions are not supported by the information posted. It also does not mean that no outcome data were collected. It means that the registry record, as posted, does not include the result or analysis needed to evaluate the primary question. The listed Quality of Life Questionnaire Scores are likewise not accompanied by results.

The serious adverse event summary is separate from the efficacy question. It records zero serious events among 22 participants at risk, but it does not establish the absence of all adverse events or resolve the limitations of the efficacy record. Enrollment is listed as 25, and the record does not explain the difference between that number and the safety denominator.

The code-generated displays and planning illustrations on the page should be understood as summaries or hypothetical calculations, not as replacements for missing observed results. Sample-size values are planning illustrations under stated assumptions, not observed power. Overall, the record supports a description of the study design and intended endpoint, but not a conclusion about the outcome.

14. Why This Trial Matters Statistically

This study is statistically instructive because it separates a well-defined outcome question from the evidence needed to answer it. The registry record specifies a participant-level response criterion based on a reduction in wet nights during a stated stimulation period. That definition clarifies what the study intended to count. Yet the record does not post the count, an analysis denominator, or an uncertainty estimate. A defined endpoint is necessary for interpretation, but it is not itself a result.

The single-group design is another important feature. It can be used to describe outcomes among participants who receive an intervention, but it does not create a direct comparison with an alternative condition. This distinction matters when readers encounter language about improvement: a change over time and a difference attributable to an intervention are not the same statistical claim. Here, no primary outcome analysis is posted, so neither a response summary nor a comparative effect can be assessed from the registry record.

The record also illustrates why denominators need to be tied to their purpose. Enrollment is listed as 25, whereas the serious adverse event summary uses 22 participants at risk. Without an explanation of participant flow or analysis populations, those entries cannot be assumed to describe the same group. The safety denominator should not be carried over to the efficacy endpoint.

Finally, planning calculations and observed results answer different questions. The sample-size section gives an illustration under specified assumptions for a hypothetical two-arm design. It is not evidence that the current study was designed that way, and it cannot fill in missing outcome data. For readers, keeping design, endpoint, observed result, and planning scenario distinct is central to sound statistical interpretation.

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 registry record provides limited information for evaluating the study’s methods and results. Although it lists the study as completed and gives an enrollment figure, it does not post a primary outcome analysis, responder count, analysis denominator, or uncertainty estimate. It also reports zero analyses. As a result, the primary clinical question cannot be answered from the posted results.

The study is recorded as single-group, without a separate comparator. This prevents a direct between-group estimate in the registry record. The record does not provide a detailed protocol, eligibility criteria, participant characteristics, stimulation schedule, adherence information, or a full account of study procedures. The arm description is incomplete, ending while describing what the pre-stimulation log was intended to determine.

The primary outcome depends on night-time voiding logs, but the record does not explain how missing or incomplete logs were handled, how the response classification was derived in practice, or which participants were included in analysis. It does not report participant flow or reconcile the enrollment figure of 25 with the 22 participants at risk in the serious adverse event section.

The secondary outcome is named, but no result is posted for it. The registry record does not report a statistical analysis plan, multiplicity approach, sample-size justification, interim analyses, or missing-data methods. The sample-size section on the page is an illustrative calculation and should not be treated as a limitation-free account of the trial’s original design.

The posted safety summary is restricted to serious adverse events and does not provide a broader account of adverse events. These reporting gaps do not establish that the underlying procedures or analyses were absent; they mean that those details are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Foot Neuromodulation for Nocturnal Enuresis — NCT02315560.
• Registry record last updated 2018-06-12; status last verified 2018-05.
• Results first posted 2018-06-12.
• 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

The registry record describes NCT02315560, Foot Neuromodulation for Nocturnal Enuresis, as a completed, single-group study in children with bedwetting. Enrollment is listed as 25. The intervention is foot electrical stimulation using a transcutaneous electrical nerve stimulator, and the study has no separate comparator listed.

The primary endpoint is the number of participants with improvement of at least 1 wet night reduction during the 6-week stimulation period, measured using a night-time voiding log. Quality of Life Questionnaire Scores are listed as a secondary outcome. The record reports zero analyses and does not post the primary outcome result or secondary outcome results.

The serious adverse event summary lists zero events among 22 participants at risk in the Foot Stimulation group. The registry record does not explain how that safety denominator relates to enrollment. Overall, the record documents the study’s aim and intended outcome but does not provide the results needed to assess the primary question.