Posterior Tibial Nerve Stimulation (PTNS) Plus Mirabegron to Treat Refractory OAB Symptoms (PTNS-M Study): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Posterior Tibial Nerve Stimulation (PTNS) Plus Mirabegron to Treat Refractory OAB Symptoms (PTNS-M Study) (NCT04907032), a randomized phase 4 study. The primary outcome is Change in the Number of UUI Episodes Over a 3-day Voiding Diary Pre- vs. Post-treatment. This Includes a Baseline Measure Pre-trial and a Pos-trial Measure in 12 Weeks.

2. Clinical Question

The trial addresses whether adding mirabegron to PTNS is associated with a different change in UUI episodes than PTNS with placebo. Its primary endpoint is a change score rather than a single post-treatment measurement: diaries were completed before the course and immediately after it. The registry describes a sample t test for comparing the difference between those measurements across groups.

The posted primary results give a mean change of 9.4 UUI episodes for PTNS with mirabegron and 5.3 for PTNS with placebo. The reported mean difference is 4.1, with a 95% confidence interval from 1.411 to 6.789 and an unadjusted p-value of 0.003. These are results for the endpoint as recorded; the registry does not specify the sign convention for the change score in enough detail to translate the positive values into a direction of symptom improvement.

3. Trial Design

This was a randomized, parallel-group, phase 4 clinical trial sponsored by the University of Alabama at Birmingham. The registry record lists 54 participants enrolled and the trial status as completed. The record gives a start date of 2021-10-01 and a primary completion date of 2023-04-01.

Participants were assigned to PTNS with mirabegron or PTNS with placebo. The intervention description specifies daily mirabegron at 50 mg for the 12-week course; the placebo was also described as daily during that course. PTNS was used in both groups. The registry lists masking as none, so this was not a masked trial according to the record.

The brief summary describes a planned allocation of 27 participants to each group. The posted primary outcome data have 20 participants in the mirabegron group and 26 in the placebo group; the registry does not explain the difference between the planned group sizes and the numbers contributing to the posted outcome results. Adverse-event results list 27 participants at risk in each group.

Randomization makes the comparison between groups the central basis for interpretation, but it does not by itself resolve questions about missing outcome data, adherence, or how the analysis handled participants without a recorded endpoint. Those details are not reported in the registry record. The trial’s own sample-size justification, allocation procedures beyond randomized assignment, and any interim analyses are also 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: 54 subjects were randomized and participated in the informed consent process. 7 subjects in the mirabegron plus posterior tibial nerve stimulation arm did not complete the study because they did not comply with showing up for all 12 study visits. There was 1 subject in the placebo to match plus posterior tibial nerve stimulation group who did not complete the study for the same reason.

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.

Population: Ch-squared tests or Fischer's exact tests were used to measure categorical variables

6. Primary Endpoint

The registry lists the primary outcome as Change in the Number of UUI Episodes Over a 3-day Voiding Diary Pre- vs. Post-treatment. This Includes a Baseline Measure Pre-trial and a Pos-trial Measure in 12 Weeks, measured over 3 day voiding diary will be filled out prior to the 12 week PTNS trial and voiding diary will be filled out immediately after the 12 week PTNS trial.

The primary endpoint is the change in the number of UUI episodes recorded in a 3-day voiding diary before and after the 12-week PTNS course. The registry describes a baseline diary before treatment and a post-treatment diary immediately after the course. This endpoint captures a symptom frequency over a defined recording period rather than relying solely on a general impression of symptoms.

Change scores can focus a comparison on how measurements differ from baseline to follow-up. In this trial, however, the posted record does not specify the exact sign convention used for calculating change. The group means should therefore be read as the recorded mean changes, without assuming from their positive signs alone whether they represent fewer or more episodes.

Diary-based episode counts are relevant to the stated question because the trial aims to compare change in UUI episode frequency. The registry also lists symptom distress and quality-of-life measures as secondary outcomes. Those measures address related but distinct aspects of the participants’ experiences, and they do not replace the primary diary endpoint.

7. Results Posted in the Registry

• Posterior Tibial Nerve Stimulation With Mirabegron: mean 9.40 versus 5.30 on control; difference 4.10 (95% CI 1.41 to 6.79), standardized effect d = 0.85; z-test p = 0.003.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Change in Symptom Distress as Measured by the Urinary Distress Index (UDI-6) Questionnaire Pre- (Baseline Measure) vs. Post-treatment (Post-trial Measure)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Posterior Tibial Nerve Stimulation With Mirabegron: mean 23.60 versus 16.30 on control; difference 7.30 (95% CI -0.51 to 15.11), standardized effect d = 0.54; z-test p = 0.067.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Posterior Tibial Nerve Stimulation With Mirabegron and the control. The interval gives the range of effects that remain compatible with the data.

Change in UUI (Urge Urinary Incontinence)/OAB (Overactive Bladder) Quality of Life as Measured by the Incontinence Impact Questionnaire Short Form (IIQ-7) Questionnaire Pre- (Baseline Measure) vs. Post-treatment (Post-trial Measure in 12 Weeks)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Posterior Tibial Nerve Stimulation With Mirabegron: mean 29.70 versus 20.20 on control; difference 9.50 (95% CI -0.69 to 19.69), standardized effect d = 0.54; z-test p = 0.068.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Posterior Tibial Nerve Stimulation With Mirabegron and the control. The interval gives the range of effects that remain compatible with the data.

Change in UUI (Urge Urinary Incontinence)/OAB (Overactive Bladder) Quality of Life as Measured by the Overactive Bladder Questionnaire-Short Form (OAB-q SF) Questionnaire Pre- (Baseline Measure) vs. Post-treatment (Post-trial Measure)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Posterior Tibial Nerve Stimulation With Mirabegron: mean 53.60 versus 33.30 on control; difference 20.30 (95% CI 1.30 to 39.30), standardized effect d = 0.61; z-test p = 0.036.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Posterior Tibial Nerve Stimulation With Mirabegron than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes cover symptom distress and quality of life, which complement the primary diary-based measure but assess different constructs. The registry lists the UDI-6, IIQ-7, and OAB-q SF measures. Across them, the reported mean contrasts are positive, but the uncertainty differs: some confidence intervals include zero while another does not. This variation means the secondary findings do not form a uniformly precise pattern.

These outcomes are related to the primary question because changes in distress and quality of life may accompany changes in UUI symptoms. They are not interchangeable with the number of episodes, however. A diary endpoint records symptom frequency over a defined period, whereas questionnaire scores summarize reported distress or impact. The registry’s endpoint descriptions do not support treating a change in one measure as proof of a corresponding change in another.

The secondary results should be read as supportive or exploratory context rather than as independent confirmation of the primary result. The registry reports unadjusted comparisons and does not describe a correction for testing multiple outcomes. General statistical principle: testing several outcomes increases the chance that at least one result appears noteworthy by chance, so unadjusted secondary p-values carry less weight than a prespecified primary test when the multiplicity strategy is unknown.

The record does not report a separate analysis plan or reported analyses for these endpoints. It also does not make clear the sign convention for all change measures. Consequently, the overall pattern is best described in terms of reported mean contrasts and their uncertainty, without asserting a consistent direction of benefit across questionnaire measures.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Change in Symptom Distress as Measured by the Urinary Distress Index (UDI-6) Questionnaire Pre- (Baseline Measure) vs. Post-treatment (Post-trial Measure)
• Change in UUI (Urge Urinary Incontinence)/OAB (Overactive Bladder) Quality of Life as Measured by the Incontinence Impact Questionnaire Short Form (IIQ-7) Questionnaire Pre- (Baseline Measure) vs. Post-treatment (Post-trial Measure in 12 Weeks)
• Change in UUI (Urge Urinary Incontinence)/OAB (Overactive Bladder) Quality of Life as Measured by the Overactive Bladder Questionnaire-Short Form (OAB-q SF) Questionnaire Pre- (Baseline Measure) vs. Post-treatment (Post-trial Measure)

9. Statistical Interpretation

10. Statistical Methods Explained

What does the mean difference represent?

The primary outcome is continuous, and the registry reports group means and standard deviations. A mean is the arithmetic average of the recorded endpoint values in a group. The mean difference compares the average recorded change in the mirabegron group with the average in the placebo group. In the posted results, that difference is 4.1 UUI episodes.

A difference between means is a measure of contrast on the endpoint’s original scale. It is not the same as a standardized effect size, which expresses a contrast relative to variability. The posted results also include a standardized effect estimate, but the main interpretation can stay with the mean difference because it retains the unit used for the outcome. The registry does not explain whether a particular difference is clinically important.

Why use a t test?

The registry’s primary-outcome description says that the difference between baseline and post-treatment measures was compared with a sample t test. A t test is a general method for assessing whether a mean contrast is compatible with a null value of zero, given the observed data and assumptions of the test. For a two-group comparison, the analysis uses the group means and the variability and sample sizes to quantify uncertainty.

As a general statistical point, the t-test framework is most straightforward when observations are independent and the outcome distribution is sufficiently well behaved for the mean and its standard error to be useful. The registry does not report diagnostic checks, transformations, a robust alternative, or a detailed model specification. It also does not state whether the exact variance assumption was equal or unequal across groups. Those details are not reported in the registry record.

How should the p-value be read?

The unadjusted p-value for the primary comparison is 0.003. In general, a p-value describes how unusual data at least as discordant with a specified null hypothesis would be if that null hypothesis and the analysis assumptions were correct. It is not the probability that the null hypothesis is true, nor does it express the size or clinical importance of the group difference. Here, the p-value is labeled unadjusted, so it is not presented as accounting for testing across the primary and secondary outcomes.

The registry identifies a sample t test but does not report a full statistical analysis plan. In particular, the planned significance threshold for the primary test, the handling of multiple outcomes, and any prespecified covariate adjustment are not reported in the registry record. These omissions limit assessment of whether the displayed analysis followed a detailed prespecified plan.

What do standard deviations and confidence intervals convey?

A standard deviation describes the spread of individual values around a group mean. The primary standard deviations are 3.9 in the mirabegron group and 5.4 in the placebo group. A larger standard deviation indicates more dispersion in the recorded values, not a larger standard error or a more precise mean.

A confidence interval gives a range of values for the population contrast that are compatible with the observed data under the statistical method and its assumptions. The primary interval runs from 1.411 to 6.789. It describes uncertainty in the mean difference, not the range containing most individual participants’ outcomes. General statistical interpretation of a 95% confidence interval is tied to the repeated use of the same method under its assumptions; it is not a statement that 95% of individual values fall inside the interval.

Why can variation affect precision?

General statistical principle: for a fixed sample size, greater outcome variability tends to make a mean estimate less precise, while more observations tend to improve precision. The primary endpoint has standard deviations that are not identical across the groups, and the analysis uses unequal observed group counts. The registry does not give enough detail to determine how variance differences were handled in the reported test, so that aspect should not be assumed.

Over-dispersion is a general concern when count outcomes vary more than a simple count model would expect. The endpoint is a count of UUI episodes, but the posted analysis describes a t test on a continuous change measure. The record does not report a count-model analysis, a distributional assessment, or an over-dispersion assessment. That absence does not establish that the t test is inappropriate; it means the registry does not provide enough information to evaluate alternative modeling choices.

What is and is not reported about the analysis?

The brief summary mentions Student’s t test and chi-squared or Fisher’s exact tests for demographic and baseline data as appropriate. For the primary endpoint, it describes a sample t test. The registry does not report a detailed protocol-level analysis plan, covariate-adjusted results, interim analyses, missing-data procedures, or analysis-population definitions. It also does not post separate reported analyses for the secondary endpoints. The interpretation should therefore distinguish the posted summary statistics and recalculated unadjusted comparisons from any sponsor analysis that is not present in the registry record.

11. Confidence Intervals and Precision

The primary mean difference is 4.1 UUI episodes, with a reported 95% confidence interval from 1.411 to 6.789. The interval describes uncertainty in the group mean contrast, given the observed data and the assumptions of the analysis. Its endpoints are both on the positive side of zero, consistent with the reported unadjusted p-value of 0.003.

Precision is not the same as clinical importance. The interval indicates a range of plausible values for the mean contrast under the statistical model, but the registry does not give a threshold for a clinically meaningful difference. The meaning of the contrast’s direction is also limited by the registry’s lack of a clearly stated sign convention for the change score.

The observed outcome counts are 20 and 26. With these counts, uncertainty can be affected by both the amount of variation in individual outcomes and the number of observations. The primary standard deviations are 3.9 and 5.4. They indicate variability among recorded change scores, not the precision of the group difference itself.

Confidence intervals for the secondary comparisons vary in whether they include zero. They should be interpreted in light of their own endpoint definitions and the fact that the registry does not report a multiplicity adjustment. None of the intervals by itself resolves questions about missing outcome data or analysis populations, which are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total participants or total events. They use the observed primary effect as a planning reference and consider planning for 100%, 75%, or 50% of that effect. For the primary endpoint, the corresponding figures are 22, 39, and 87 participants per arm for 80% power, and 29, 52, and 116 participants per arm for 90% power.

The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. In plain language, the 80% power column describes the number of participants per arm that the planning calculation estimates would give an 80% chance of detecting the specified effect under those assumptions. The 90% column gives the corresponding estimate for a 90% chance. These are planning illustrations, not observed power.

The smaller the effect targeted for detection, the more participants are needed under the same calculation assumptions. This is why the planning figures increase when the calculation uses a smaller fraction of the observed effect. These calculations are not the trial’s documented original design justification. The trial’s own sample-size assumptions and justification are not reported in the registry record.

These figures depend on assumptions that may not match the realized trial, including equal allocation and the normal approximation. They should not be read as a post hoc verdict on the design or as evidence about whether the trial was adequately powered for effects other than the particular planning scenarios.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 4.100; pooled standard deviation σ = 4.810.
2. n = 2 × (1.96 + 0.842)² × 4.810² / 4.100² = 21.6, rounded up to 22 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 4.1                      # observed difference in means
sigma <- 4.81000378000229                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4907032)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 22 (80% power), 29 (90% power)
 75% of observed effect: n per arm = 39 (80% power), 52 (90% power)
 50% of observed effect: n per arm = 87 (80% power), 116 (90% power)
power.t.test: 22.6 
Simulated power at n = 22 per arm: 0.783 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry posts one primary endpoint and three secondary endpoints. Each has a group comparison, but the secondary comparisons are labeled with unadjusted p-values. No multiplicity adjustment or hierarchy for interpreting the secondary outcomes is reported in the registry record. It is also not reported whether the primary endpoint was the sole confirmatory test or whether additional planned outcomes were intended to contribute to formal claims.

General statistical principle: when several hypotheses are tested, the chance of at least one apparently significant result can increase if each is judged separately at the same threshold. Methods such as a prespecified hierarchy or multiplicity adjustment can control that issue, but the record does not state that such a method was used. The secondary p-values should therefore not be treated as if they were adjusted or as independent replications of the primary endpoint.

The registry does not report how missing endpoint data were handled, how many participants lacked each measure, or whether any imputation or sensitivity analysis was used. It also does not report defined analysis populations, such as intention-to-treat or per-protocol populations. The primary outcome counts are 20 and 26, while the brief summary describes planned groups of 27 each. Without an account of these counts, the potential influence of missing outcomes cannot be evaluated from the registry record.

Random assignment is important for an unbiased comparison, but the interpretation also depends on how participants are retained in the analysis and how missing data are addressed. These procedures, any interim analyses, and the full statistical analysis plan are not reported in the registry record. No assumptions about those procedures should be inferred from the posted summary statistics.

15. 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 2% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event results list 27 participants at risk in each group. In the PTNS-with-mirabegron group, 0 participants were affected by a serious adverse event; the same figure, 0, is listed for the PTNS-with-placebo group. The registry lists 0 deaths in each group. No serious adverse-event terms are listed.

For other adverse events, the record lists 6 affected participants in each group. These figures count participants affected, as described in the registry; they do not give event severity, timing, duration, or a detailed account of event types. The record also does not establish whether events were judged related to treatment.

These are descriptive counts, not a complete safety comparison. A zero count in the posted record does not establish that an event cannot occur, and the equal counts for other adverse events do not show that the event profiles were identical. The registry does not report further detail needed to characterize the nature or timing of these events.

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

The primary posted results show a mean difference of 4.1 UUI episodes between the recorded change scores for PTNS with mirabegron and PTNS with placebo. The 95% confidence interval is from 1.411 to 6.789, and the unadjusted p-value is 0.003. Statistically, this is evidence of a difference in the reported group means under the assumptions of the analysis.

That statement is narrower than a claim about treatment benefit. The registry does not clearly specify the direction used to calculate change, and it does not report a threshold for clinical importance. The positive mean values and positive contrast therefore cannot by themselves establish whether the groups experienced more or fewer episodes relative to baseline, or whether the size of the contrast matters to participants.

The results also do not establish that all participants had outcomes close to their group average. The standard deviations indicate variability, and the confidence interval concerns the estimated mean difference rather than individual responses. Secondary questionnaire findings offer additional context, but they are unadjusted and have varying precision.

The reported comparison applies to the participants contributing outcome data in the registry record. The difference between the planned group sizes and posted primary outcome counts is not explained. Missing-data handling and analysis populations are not reported, so the effect of incomplete outcome data cannot be judged.

In general, a randomized comparison can help estimate differences between assigned groups, but the strength and scope of conclusions depend on the conduct, measurement, and analysis details. The registry record does not provide all of those details. The safest reading is a reported difference in the primary recorded change measure, with uncertainty quantified by the confidence interval and important questions about direction, clinical relevance, and missing data left unresolved.

17. Why This Trial Matters Statistically

This trial is statistically informative because it compares two groups that both received PTNS, with mirabegron or placebo distinguishing the assigned regimens. That design focuses the comparison on the addition of mirabegron within the study’s treatment context, rather than comparing PTNS with no PTNS. Randomization supports the intended between-group comparison, although the registry record does not provide all details needed to assess implementation or analysis.

The primary endpoint is a change in a symptom-frequency measure collected using a voiding diary. The trial also includes measures of distress and quality of life, making clear that symptom frequency and patient-reported impact are distinct outcomes. Examining more than one dimension can broaden the description of outcomes, while also raising the need for a transparent plan for interpreting multiple tests.

The posted primary estimate is accompanied by a confidence interval, rather than being presented only as a p-value. That makes the estimated contrast and its uncertainty available for interpretation. The planning illustrations also show how required group sizes depend on the effect targeted and the chosen power level, while remaining separate from the original design justification, which is not reported in the registry record.

At the same time, the registry leaves important statistical questions unresolved: the sign convention for change, the handling of missing measurements, the analysis populations, and the multiplicity plan. These gaps matter because precision and interpretation depend not only on the numerical estimate but also on how the estimate was defined and which participants contributed data. The trial is a useful case for distinguishing evidence of a statistical difference from a complete account of its clinical meaning.

18. 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 specific to this trial affect interpretation. First, the registry describes the endpoint as change from baseline to post-treatment but does not clearly state the subtraction order. That makes the direction of the positive mean difference difficult to translate into improvement or worsening from the posted results alone.

Second, the primary outcome counts are 20 for PTNS with mirabegron and 26 for PTNS with placebo, while the brief summary describes 27 planned participants in each group. The record does not explain why the posted analysis counts differ, how many measurements were missing, or how missing data were handled.

Third, the registry lists no masking. Participants and study personnel may have known the assigned group, but the record does not describe how this affected outcome collection or assessment. Because the endpoint includes a participant-completed diary, the lack of masking is relevant context, not evidence by itself that the measurements were biased.

Fourth, the statistical plan is incompletely described. The registry does not report a full prespecified analysis plan, a multiplicity approach, analysis-population definitions, sensitivity analyses, interim analyses, or covariate-adjusted results. The secondary comparisons are unadjusted. The record also does not provide a clinical-importance threshold for the primary endpoint or a clear sign convention for all change measures.

Finally, the posted adverse-event information is limited to counts of affected participants and deaths; detailed event descriptions, timing, and relatedness are not reported. These gaps restrict the conclusions that can be drawn from the registry record, even when the numerical comparison itself is stated precisely.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Posterior Tibial Nerve Stimulation (PTNS) Plus Mirabegron to Treat Refractory OAB Symptoms (PTNS-M Study) — NCT04907032.
• Registry record last updated 2023-07-20; status last verified 2023-06.
• Results first posted 2023-07-20.
• 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.

22. Record Summary

NCT04907032 is a completed, randomized, parallel-group phase 4 trial sponsored by the University of Alabama at Birmingham. It enrolled 54 participants and compared PTNS with mirabegron against PTNS with placebo in women with refractory overactive bladder symptoms. The registry lists no masking and describes a 12-week treatment course.

The primary endpoint was change in UUI episodes recorded with a 3-day voiding diary. The posted mean difference is 4.1, with a 95% confidence interval from 1.411 to 6.789 and an unadjusted p-value of 0.003. The record also lists three secondary questionnaire outcomes. It does not report the sign convention for change, missing-data procedures, analysis populations, or a multiplicity plan.