Fractional CO2 Vaginal LASER Therapy for Recurrent Urinary Tract Infection: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Fractional CO2 Vaginal LASER Therapy for Recurrent Urinary Tract Infection (NCT04301934), a randomized na study. The primary outcome is Prevalence of Urinary Tract Infections (UTI).

2. Clinical Question

3. Trial Design

The registry describes a randomized, double-masked, parallel-group trial comparing fractional CO2 vaginal laser therapy with vaginal estrogen therapy. Randomization means assignment to a study group is intended to use a chance-based process. In general, this can reduce the influence of measured and unmeasured baseline differences, although it does not guarantee that groups will be alike, particularly in a study with limited enrollment. The record does not report the randomization method, allocation concealment procedures, or masking details.

The registered enrollment is 12, and the trial status is completed. The registry dates are a start date of 2020-06-01 and a primary completion date of 2023-04-30. The phase is listed as NA. Mayo Clinic is identified as the sponsor. These registry entries describe the study’s recorded design and administrative status; they do not establish how many participants completed treatment or contributed outcome data.

The laser group was assigned 3 treatments, 6 weeks apart. The estrogen group was offered one of two vaginal estrogen creams on the schedules described in the record. The registry lists conjugated estrogen and estradiol as drug interventions and Mona Lisa Touch as a device intervention. It does not report whether treatment changes, discontinuations, or deviations occurred, or how those were handled in analyses.

A parallel-group design assigns participants to a treatment group and evaluates outcomes across groups, rather than having each participant receive both study treatments. Double masking indicates that the registry classifies the trial as double-masked, but the record does not specify which parties were masked or how masking was maintained. The primary outcome timeframe is 4 months. The record does not state the timing of every assessment or provide a participant flow description. Consequently, the design can be outlined, but the available registry information does not support a detailed account of implementation or follow-up.

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

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 Prevalence of Urinary Tract Infections (UTI), measured over 4 months.

The primary endpoint is described as prevalence of urinary tract infections, measured as the percentage of subjects with none versus one or more UTI at 4 months. It is a binary event-status outcome: participants are classified according to whether they had at least one UTI during the relevant assessment period, with the other category representing none. The record uses the term prevalence and identifies the unit as percentage of subjects.

This type of endpoint can provide a clinically interpretable description of how common the event was in each treatment group at a specified assessment. In general, a binary outcome is useful when the research question concerns the proportion of participants experiencing an event rather than the number or timing of episodes. However, an outcome defined as none versus one or more does not, by itself, distinguish a single episode from multiple episodes. The registry record does not report a separate count of UTI episodes or clarify the precise period used to classify status at 4 months.

The endpoint description does not include the observed percentages, the number of participants in each category, an effect estimate, or a confidence interval. Those results are not reported in the registry record. Without them, the endpoint definition can be explained, but the comparative finding and its precision cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods are useful only when their assumptions and inputs match the trial data. The registry record identifies a randomized, double-masked, parallel-group design and a binary primary outcome, but it does not report a full statistical analysis plan or the primary outcome results. The explanations below describe general concepts and distinguish them from methods documented for this particular trial.

What does randomization contribute?

In general, randomization assigns participants to treatment groups by chance. Its purpose is to reduce systematic differences between groups at the point of assignment, making a later comparison more credible than a comparison based on treatment choice alone. Randomization does not guarantee balance in every characteristic, and chance imbalances can occur, especially when enrollment is limited. The record does not describe the random sequence method, any stratification factors, or allocation concealment, so those details cannot be assessed.

The registry labels the design double-masked. In general, masking can limit the influence of expectations on care, outcome assessment, or reporting. The record does not specify who was masked, whether masking applied to participants or study staff, or how masking was maintained for a device-based treatment compared with a cream. No conclusion about the success of masking can be drawn from the label alone.

How should a binary endpoint be analyzed?

The primary outcome is described as a percentage of subjects with none versus one or more UTI at 4 months. A binary outcome has two categories, but a valid comparison still requires the number of participants in each category and the appropriate analysis population for each group. The record does not report those primary-outcome counts or percentages. It also does not provide an effect measure or specify whether the intended comparison was based on a difference in proportions, a ratio, a regression model, or another method.

In general, an estimate of a group difference should be read alongside its uncertainty. A confidence interval helps show how precisely the effect has been estimated; a p-value addresses compatibility with a specified null hypothesis under an analysis model, but does not measure clinical importance. Neither a confidence interval nor a p-value for the primary outcome is reported in the registry record. It is therefore not possible to describe statistical significance or precision.

Why can over-dispersion matter?

General explanation: over-dispersion occurs when observed variability in count data exceeds what a chosen statistical model expects. It can make standard errors too small if the analysis assumes less variability than the data contain. This is relevant to some analyses of event counts, but the registered primary endpoint is described as a binary percentage, and no count-model analysis or over-dispersion assessment is reported. The record does not give a basis for claiming that over-dispersion was evaluated or that it affected the primary analysis.

What do planning calculations mean?

The stated planning assumptions describe illustrations based on a fraction of the observed effect, with a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. These are planning assumptions, not a description of the trial’s original design rationale. The record does not report the protocol’s sample-size justification, the effect size used in its original planning, or whether an interim analysis was planned. Any sample-size illustration based on an observed effect should be understood as a planning exercise, not as observed power or evidence that the trial had a particular probability of detecting an effect.

In general, sample-size calculations depend on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. Changing an assumed effect changes the resulting planning requirement. Such calculations do not establish whether a completed study’s result is reliable, and they cannot replace a reported effect estimate with its uncertainty. No calculated sample-size values or observed primary-outcome effect are reported in the registry record.

What can be concluded from the available analysis record?

The record lists one outcome measure and one analysis, but the primary outcome has multiple categories or time points and is not reduced to a single comparison in the available results. This prevents a simple unadjusted recalculation from being described. The analysis model, covariate adjustment, analysis population, missing-data method, and multiplicity strategy are not reported in the registry record. In general, those choices can affect how estimates are formed and interpreted, so an undocumented analysis cannot be reconstructed reliably from the study design alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry record does not describe how multiplicity was handled. Multiplicity arises when several outcomes, time points, groups, or statistical tests are considered. In general, conducting multiple tests can increase the chance of at least one apparently unusual result under a null hypothesis. A prespecified approach can define which result is primary and how additional comparisons are interpreted. The record identifies a primary endpoint, but it does not report a multiplicity adjustment, a testing hierarchy, or whether secondary outcomes were analyzed.

The primary outcome is framed as prevalence at 4 months, with categories of none versus one or more UTI. The available result information does not reduce the endpoint structure to a single comparison. The registry’s analysis listing does not supply the missing group results or an analysis specification. No primary-outcome estimate can therefore be reconstructed from the information reported.

Missing-data handling and analysis populations are also not reported in the registry record. It does not state how many participants had outcome data, how missing assessments were treated, or whether the main analysis followed intention-to-treat, per-protocol, or another population definition. In general, these choices matter because missing outcomes can affect both the estimated event proportion and the comparability created by randomization.

The registered enrollment of 12 should not be assumed to equal the number included in the endpoint analysis. The record does not provide a participant flow account or explain exclusions after randomization. Without those details, the extent and potential impact of missing data cannot be assessed.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: urospepsis with positive urine and blood cultures (14.3%), acute diverticulitis (14.3%).

The adverse-event record reports serious adverse events among 2 of 7 participants at risk in the Vaginal Estrogen Therapy Group and 0 of 5 participants at risk in the Laser Therapy Group. It reports other adverse events among 3 of 7 participants at risk in the estrogen group and 3 of 5 participants at risk in the laser group. Deaths are reported as 0 in each group. These are the recorded group-specific figures; they do not establish that all participants had complete safety follow-up or that every event was caused by the assigned treatment.

The registry lists “Urospepsis with positive urine and blood cultures” and “Acute diverticulitis” among the top serious terms, each at 14.3%. The record does not identify the treatment-group attribution for these listed terms. They should therefore be read as registry-listed event terms, not as evidence that a particular group experienced a specific term.

In general, adverse-event counts are descriptive safety information. Small group risk sets can make percentages sensitive to individual events, and a count of participants with an event is not the same as a count of all events if one participant can experience more than one. The record does not explain its event-counting rules, relatedness assessments, or the observation period for safety. These figures alone do not establish comparative safety or causation.

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

The trial addresses a direct comparison between fractional CO2 vaginal laser therapy and vaginal estrogen therapy for women with recurrent urinary tract infection. Its randomized, double-masked, parallel-group design is relevant to evaluating a treatment comparison, and the registry identifies a primary outcome at 4 months. Those features define the question; they do not provide the answer.

The primary outcome results are not reported in the registry record. Consequently, the posted information does not show the observed prevalence in either group, the size or direction of a difference, or the precision of a comparison. It cannot establish whether the treatments had similar or different observed results on the primary endpoint. It also cannot support a conclusion about the size or importance of any potential difference.

The registered enrollment is 12, but the record does not state the number contributing primary-outcome data or give a participant flow. The adverse-event data are available as separate safety entries, but they do not substitute for the primary efficacy outcome. Nor do the adverse-event figures, by themselves, establish that an event was caused by a treatment or that the groups differed in safety.

In general, a completed trial can still have incomplete public results. A registry description of the protocol and outcome definition is not equivalent to a report of the trial’s outcome analysis. Interpreting comparative results typically requires group-specific outcome data, a defined analysis population, an effect estimate, and an uncertainty measure. These are not reported for the primary endpoint.

The appropriate statistical reading is therefore bounded. The registry record documents a randomized comparison and describes what the primary outcome was intended to measure, but the posted results do not permit an assessment of the primary treatment comparison. This is a limitation of the information recorded, not evidence for either similarity or difference between the interventions.

13. Why This Trial Matters Statistically

This trial is statistically notable because it frames a randomized comparison of a device-based procedure with vaginal estrogen therapy while specifying a binary clinical endpoint. The question involves the prevalence of UTI at 4 months, categorized as none versus one or more. That format is straightforward to communicate, but it does not retain information about how many episodes occurred among participants in the one-or-more category.

The registry’s design labels also matter for interpretation. Randomization is intended to support comparability between groups, and masking is intended to reduce some sources of bias. However, these design features cannot replace reporting of the actual outcomes. A completed randomized trial without posted primary results leaves readers unable to evaluate the observed effect, its uncertainty, or whether the analysis followed the intended approach.

The registered enrollment of 12 makes transparent reporting especially important. In general, results from limited enrollment can be imprecise, and individual observations can have substantial influence on group percentages. The registry record does not provide the primary outcome counts or confidence intervals needed to evaluate that issue directly.

The safety entries illustrate another statistical distinction: descriptive adverse-event counts are not the same as a controlled comparison of the primary endpoint. The group-specific serious and other adverse-event figures are useful to read as recorded safety information, but the registry does not supply enough detail to attribute listed serious terms to a group or infer causation.

Overall, the record makes the intended question and design identifiable, while leaving the main efficacy comparison unresolved in the posted results. That distinction is important in evidence appraisal: a clear trial question can coexist with insufficient outcome reporting for a statistical conclusion.

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 main trial-specific limitation is that the registry record does not report the primary outcome results. Although it defines the 4-month endpoint, it does not provide group-specific percentages or counts for participants with none versus one or more UTI. No primary effect estimate, confidence interval, or p-value is available, preventing assessment of direction, magnitude, and precision.

The registered enrollment is 12, but the record does not provide a participant flow account, the number completing treatment, or the number included in the primary analysis. The safety risk sets are reported separately and cannot be assumed to be the primary-outcome denominators. Missing-data methods and analysis populations are not reported in the registry record.

The record identifies the estrogen comparator as either conjugated estrogen or estradiol, but it does not explain how the preparation was selected, whether participants were analyzed together, or whether the preparations were compared separately. It also does not provide further details about the laser procedure beyond the treatment schedule, or describe treatment adherence and deviations.

Although the trial is labeled double-masked, the record does not identify who was masked or how masking was maintained. The randomization method and allocation concealment are not reported. The statistical analysis plan, multiplicity approach, and protocol-based sample-size justification are also not reported in the registry record.

These limitations restrict interpretation of the available record; they do not demonstrate that the study was conducted incorrectly. They mean that key information needed to evaluate the primary comparison and its uncertainty is unavailable in the registry entry.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Fractional CO2 Vaginal LASER Therapy for Recurrent Urinary Tract Infection — NCT04301934.
• Registry record last updated 2024-03-26; status last verified 2024-03.
• Results first posted 2024-03-26.
• 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 record describes a completed, randomized, double-masked, parallel-group trial sponsored by Mayo Clinic, with enrollment of 12. It compares fractional CO2 vaginal laser therapy with vaginal estrogen therapy in women with recurrent urinary tract infection. The laser group was assigned 3 treatments, 6 weeks apart; the estrogen group was offered conjugated estrogen or estradiol cream on the schedules recorded for those treatments.

The primary outcome is prevalence of UTI at 4 months, expressed as the percentage of subjects with none versus one or more UTI. The registry record does not report the primary outcome results, an effect estimate, or its precision. Safety entries report group-specific serious and other adverse events and 0 deaths in each group; attribution of the listed serious-event terms to treatment groups is not reported.

Important analysis details, including missing-data handling, analysis populations, multiplicity methods, and the protocol’s sample-size justification, are not reported in the registry record.