Comparison of the Viveve Treatment and Cryogen-Only Treatment Versus Sham Treatment for Stress Urinary Incontinence: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of the Viveve Treatment and Cryogen-Only Treatment Versus Sham Treatment for Stress Urinary Incontinence (NCT04206085), a randomized na study. The primary outcome is 1-hour Pad Weight Test.

2. Clinical Question

In statistical terms, the design creates two active-treatment comparisons with a common sham comparator. However, the posted outcome summaries are group-specific rather than estimates of those treatment contrasts. They can describe the observed changes in each arm, but alone they do not establish whether changes differed between arms or how precisely any between-arm difference was estimated.

3. Trial Design

The registry describes a prospective, randomized, single-blind, parallel study. It lists three groups: active treatment with radiofrequency and cryogen, cryogen alone, and sham treatment. The registry enrollment is 38. The study is marked completed; its recorded start date is 2020-01-01 and its primary completion date is 2020-08-30.

Randomization means that assignment to the study groups was intended to be determined by chance, rather than chosen solely by participants or investigators. This can support fair comparisons by reducing systematic differences between groups at the outset. The record does not report the randomization method, allocation concealment, or whether any stratification was used. It identifies the study as single-blind but does not say which people were masked or describe how masking was maintained.

A parallel design assigns participants to a group and evaluates the groups over the same study period; it is different from a crossover design in which participants receive multiple treatments in sequence. The registry does not report the planned allocation ratio, treatment schedule, or detailed follow-up plan beyond the primary outcome timeframe.

The primary endpoint was the change in 1-hour Pad Weight Test values at 5 months from baseline. The outcome population is described as the full analysis set. The registry lists one outcome measure and no posted analyses. It does not report a protocol-based sample-size justification or a detailed statistical analysis plan. Such details should not be inferred from the registry enrollment or from the posted outcome summaries.

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:

Analysis population for the primary outcome, as defined in the registry: Full analysis set used.

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 1-hour Pad Weight Test, measured over Change in 1 hour Pad Weight Test Values at 5 Months from Baseline.

The 1-hour Pad Weight Test assesses leakage by measuring the weight of a standardized pad after the participant completes a set sequence of activities. The registry describes the participant wearing a pre-weighed pad without voiding, drinking a specified liquid, walking and climbing stairs, then performing activities that include standing from sitting, coughing, running on the spot, and bending. The pad is weighed at the end of the test. A greater pad weight reflects more liquid collected by the pad during the test, although the registry does not specify how the reported change was calculated or which subtraction order was used.

The primary outcome is the change in test values at 5 months from baseline, reported as a median for each group. A change score focuses on how the measurement differs from its baseline value rather than reporting only the later measurement. This can be useful for describing the course of an outcome over follow-up, but interpretation depends on a clear definition of the change and on complete, consistent measurement. The subtraction convention is not reported in the registry record, so the sign of a change should not be assigned a direction such as improvement or worsening based on the posted summary alone.

Pad weight is an objective measurement of leakage during a standardized challenge, but it represents performance during that test rather than every aspect of stress urinary incontinence in daily life. The registry reports a stated 25% confidence interval with each median. It does not explain the interval's construction or provide the underlying individual measurements.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The outcome is summarized by a median rather than a mean. In general, the median is the midpoint of ordered observations: half the observations lie at or below it and half at or above it, subject to the usual conventions for an even number of observations. It is less sensitive than the mean to very large or very small observations. That can be useful when an outcome is skewed, but the registry does not state why the median was chosen or describe the distribution of individual pad-weight changes.

Each reported median is accompanied by limits described as a 25% confidence interval. A confidence interval is a method-based way of expressing uncertainty in an estimate, not a guarantee that a particular proportion of individual observations falls between its limits. Its meaning depends on the confidence level and construction method. The record does not explain either in detail. The stated level should be retained as recorded; these limits should not be re-labelled or interpreted as a conventional interval at another confidence level.

It is also important to distinguish an interval around an arm-specific median from an interval around a difference between arms. The former describes uncertainty about a summary within one group. A treatment comparison needs an estimate of the contrast between groups, with uncertainty calculated for that contrast. The posted record gives separate arm summaries but no such contrast. Even when two separate intervals overlap or do not overlap, that observation alone does not constitute the registry's formal test of a between-group difference.

What does randomization contribute?

In general, random assignment is designed to make treatment groups comparable in expectation with respect to measured and unmeasured baseline factors. It supports causal interpretation when the study is conducted and analyzed appropriately, but it does not guarantee that groups are identical in a particular trial. The record identifies the design as randomized, but does not give enough detail to assess the assignment procedure, concealment, baseline balance, or departures from assigned treatment. Randomization also does not replace a direct statistical comparison of outcomes.

What can be inferred from the posted summaries?

The summaries describe the observed median change in each arm and the corresponding limits recorded for that median. They do not show the distribution of observations, how many observations contributed at each assessment, or whether influential values were present. The arm-specific figures therefore support descriptive reading, not reconstruction of participant-level data or a new comparison. The record lists no posted analyses, and the two-arm comparison values are not estimable for this endpoint in the registry record.

In general, statistical tests and confidence intervals rely on assumptions appropriate to the outcome and design. For example, over-dispersion—variation greater than a model expects—can make standard errors too small if the model does not allow for it. That general issue cannot be evaluated from these summaries: no model, variance assumptions, or analysis procedure is reported. It would be inappropriate to invent an analysis or calculate a new p-value from the medians and limits.

How should the change score be read?

A change score compares a follow-up measurement with a baseline measurement. The registry identifies the timeframe as change at 5 months from baseline, but does not state whether the change was calculated as follow-up minus baseline or baseline minus follow-up. The reported negative medians therefore should be quoted as recorded rather than described as reductions or improvements. The test itself measures pad weight after a standardized activity sequence; the reported change is not a direct description of all symptoms or daily experience.

The registry says the full analysis set was used. In general, an analysis population defines which participants contribute to a particular estimate. The label alone does not reveal how the set was defined, what happened to missing measurements, or whether participants were analyzed according to randomized assignment. Those procedures are not reported in the registry record. This limits reproducibility and makes it difficult to assess possible bias from incomplete follow-up.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no posted analyses. It does not report a plan for controlling multiplicity, such as how to interpret results across multiple outcomes, timepoints, or treatment contrasts. The primary outcome timeframe is stated as 5 months from baseline, but the registry does not provide a broader testing hierarchy or explain whether additional analyses were planned. Without such information, the multiplicity strategy is not reported in the registry record.

The outcome population is described as the full analysis set. The record does not define that set, indicate how many participants had an observed primary endpoint, or explain how missing baseline or follow-up measurements were handled. It also does not report imputation methods, sensitivity analyses, exclusions from the analysis, or whether all randomized participants were included in the primary outcome calculation. These details matter because missing outcome data can affect both the estimate and its uncertainty, especially if the reasons for missingness are related to outcomes or treatment.

In general, missing-data methods make assumptions about the unobserved values, and different assumptions can lead to different estimates. A complete-case analysis, an imputation procedure, or a model-based approach would each require description and justification. None should be attributed to this study without registry documentation.

The available summaries consequently do not establish how missing data or multiplicity were addressed. The absence of posted analyses also means there is no reported inferential result to interpret alongside the descriptive medians.

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.

Most frequent non-serious adverse event terms

The adverse-event record reports serious events as zero in the active arm, zero in the cryogen arm, and zero in the sham arm. Deaths are also recorded as zero in each arm. The corresponding serious-event groups at risk are listed as 13, 13, and 12, respectively. These are the registry's reported counts; they should not be confused with the outcome-specific arm sizes or treated as evidence that every possible harm was excluded.

The record also lists other, non-serious adverse events: 8 in the active arm, 2 in the cryogen arm, and 4 in the sham arm. The groups at risk for those counts are recorded as 13, 13, and 12, respectively. No serious-event terms are listed. The record does not provide event descriptions for the other adverse events, their timing, severity, relationship to treatment, or the method used to collect them.

Zero reported serious events means none were recorded in these groups in the registry summary; it does not establish that a treatment is free of risk. Safety interpretation depends on the scope and duration of monitoring, definitions, completeness of reporting, and the amount of information available. Those details are not reported in the registry record. The counts are descriptive and do not, on their own, establish comparative safety.

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

The posted results show that the registry recorded different arm-specific median changes in the 1-hour Pad Weight Test at 5 months from baseline. The active-treatment median is -9.0 grams, the cryogen-only median is -6.3 grams, and the sham median is -4.4 grams. The record gives a 25% confidence interval for each median. These summaries describe the groups as recorded; they do not establish which treatment caused a difference or whether any observed difference is statistically distinguishable from chance.

A treatment effect is ordinarily assessed by directly comparing outcomes between randomized groups. The registry does not post those comparisons for this endpoint, and it reports that values are missing or not estimable for a two-arm comparison. No significance test or comparative confidence interval is reported. The group medians cannot be used to fill that gap by calculating a new contrast, and the stated interval level should not be reinterpreted.

The result also does not tell readers whether an observed change was clinically meaningful. The registry does not provide a threshold for meaningful change, a detailed interpretation of the test score, or the subtraction convention used for the change calculation. Because the direction of that calculation is unspecified, the negative values should not be labeled as improvement or worsening.

The findings are limited to the specified test and timeframe. Pad weight after a standardized activity sequence is one measurement of leakage; it does not capture every aspect of stress urinary incontinence or establish how participants experienced treatment. The registry summary does not report longer-term results or broader clinical outcomes.

In short, the posted outcome supports descriptive reporting of three arm-specific medians and their stated limits. It does not support a definitive claim that one group performed better, that treatments were equivalent, or that a treatment is effective or ineffective. Such conclusions would require appropriately reported comparative analyses and supporting clinical context.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between a randomized design and a reported comparative result. Randomization creates a design intended to support comparisons among groups, but the registry's posted primary outcome consists of separate arm-level summaries. Without an estimated between-group contrast and its uncertainty, readers cannot assess the central comparative question from those summaries alone.

The endpoint also illustrates why the estimand and its definition matter. The outcome is a change in pad weight at a stated follow-up time, but the record does not identify the subtraction order. That omission prevents a secure interpretation of the sign. A clearly defined outcome is essential both for reproducibility and for connecting statistical direction to clinical meaning.

The stated 25% confidence intervals highlight another reporting consideration: interval labels need enough detail for readers to understand what uncertainty they represent. The record does not describe their construction. Reporting an interval without a clear method or confidence level can make it difficult to compare estimates or judge precision.

Finally, the record distinguishes between describing data and making an inferential claim. Medians and interval limits can communicate observed summaries, but they do not replace a prespecified, adequately described comparison. Information about missing observations, analysis populations, and multiplicity would also help readers evaluate how robust conclusions might be. These are general statistical considerations, not evidence that any particular unreported method was or was not used in this study.

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 posted outcome information is limited to arm-specific medians and stated 25% confidence intervals. A direct comparison between each active group and sham is not reported, and the registry indicates that two-arm comparison values were missing or not estimable. There is therefore no posted comparative estimate or inferential result for the primary endpoint.

The record does not explain how the confidence intervals were constructed. It also does not report the subtraction order for the change score, so the negative median values cannot be assigned a direction such as reduction or improvement based on the registry summary alone. No underlying participant-level data or separate measure of outcome dispersion is reported.

The registry identifies the analysis population as the full analysis set but does not define it or detail missing-data handling, exclusions, or adherence to randomized assignment. It reports single blinding without specifying who was masked, and does not describe allocation concealment or the randomization procedure. Protocol details, baseline characteristics, treatment adherence, and a complete statistical analysis plan are not reported in the registry record.

For safety, the record provides counts but not descriptions of the other adverse events, collection procedures, follow-up duration, or event attribution. The recorded absence of serious events should therefore be interpreted as a reported count, not a complete assessment of risk. These limitations constrain both comparative efficacy interpretation and assessment of safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Comparison of the Viveve Treatment and Cryogen-Only Treatment Versus Sham Treatment for Stress Urinary Incontinence — NCT04206085.
• Registry record last updated 2022-09-21; status last verified 2020-05.
• Results first posted 2022-09-21.
• 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

The registry describes a completed, prospective, randomized, single-blind, parallel study of active radiofrequency plus cryogen treatment, cryogen-only treatment, and sham treatment for mild to moderate stress urinary incontinence. The registry enrollment is 38. The primary outcome is change in the 1-hour Pad Weight Test at 5 months from baseline, reported as a median with stated 25% confidence interval for each arm. The outcome population is identified as the full analysis set.

The posted summaries give arm-specific values but no analyses or estimable two-arm comparisons for this endpoint. The change-score convention and interval method are not explained. Serious adverse events and deaths are recorded as zero in each reported safety group, while other adverse-event counts are also listed. Comparative conclusions, missing-data procedures, and further statistical details are not reported in the registry record.