Real-world Evidence Study on Cystistat: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Real-world Evidence Study on Cystistat (NCT05544695), a registered phase not stated study. The primary outcome is Patient Global Assessment (PGA).

2. Clinical Question

The study is registered as an observational study intended to evaluate the performance and safety of Cystistat® in patients with interstitial cystitis or bladder pain syndrome. Its brief summary describes an aim of continuing to assess the acceptability of the benefit-risk ratio and confirming safety and performance over the device’s expected lifetime. Those aims describe the study’s purpose; they do not themselves establish an outcome.

The primary question is framed as a responder proportion rather than a comparison between treatment groups. A responder is defined by a reported improvement category on the PGA: markedly improved, moderately improved, or slightly improved. The slightly improved category counts only when the participant also answers yes to whether therapy had a positive effect on life and whether they would undergo treatment again. This rule combines a global rating with an additional condition for the mildest improvement category.

The registry lists assessments of bladder pain or interstitial cystitis symptoms, bladder-pain visual analogue scale, urinary-urgency visual analogue scale, and quality-of-life visual analogue scale as secondary outcomes. Their outcome estimates are not reported in the registry record. Without a reported comparator or outcome estimates, the record does not answer a comparative treatment question or establish the size or precision of any change.

3. Trial Design

NCT05544695 is titled “Real-world Evidence Study on Cystistat” and is marked completed in the registry record. The listed study start date is 2022-10-21, and the primary completion date is 2024-07-29. Enrollment is 74. MEDA Pharma GmbH & Co. KG is listed as the sponsor.

The study is described as observational, with intravesical sodium hyaluronate (Cystistat®) listed as the intervention. The registry’s safety group is named “Single Arm: Cystistat® 40 mg/50 mL Solution.” A randomized allocation process is not described; allocation is not stated. A concurrent control group and a like-for-like comparator are not reported in the registry record. Consequently, the design information does not support a randomized between-group interpretation.

The record describes Cystistat® as a 50 mL solution containing 40 mg of sodium hyaluronate and indicates it for temporary replacement of the GAG layer in the bladder. These are descriptions of the device and its indicated use, not evidence about its outcomes in this study. The stated study aim is to assess performance and safety and to continue evaluating the acceptability of the benefit-risk ratio over the device’s expected lifetime.

The primary endpoint is a PGA responder percentage assessed up to week 12. The primary analysis population is identified as the full analysis set, but the size and membership of that set are not reported in the registry record. The registry lists five outcome measures in total: the PGA primary outcome and four secondary assessments covering symptoms, pain, urgency, and quality of life. No results for these outcomes are reported in the registry record, and no statistical analyses are listed.

Other design details—including recruitment setting, eligibility criteria, participant flow, treatment schedule, follow-up completeness, and the operational definition of the full analysis set—are not reported in the registry record. Without those details, readers cannot fully assess how participants entered the study, how the observational assessments were conducted, or which enrolled participants contributed to each outcome.

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: One patient did not receive study treatment due to withdrawal of consent.

Overall Study

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

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 Patient Global Assessment (PGA), measured over Up to week 12.

The primary endpoint is the percentage of participants classified as responders on the Patient Global Assessment (PGA) up to week 12. The registry defines a responder as someone whose PGA is markedly improved, moderately improved, or slightly improved. For a slightly improved rating to qualify, the participant must also answer yes to the question about whether therapy had a positive effect on life and whether they would undergo the treatment again.

This endpoint is a participant-level global assessment. In general, a global assessment can capture a person’s overall perception of change rather than isolating one symptom or measurement. That can be useful when a condition involves several symptoms or effects on daily life. The PGA responder rule also makes the classification explicit: a mild improvement rating alone is not sufficient under the registered definition.

The endpoint is reported as a percentage and is paired in the registry description with a 90% confidence interval. A confidence interval would express uncertainty around an estimated responder percentage; its actual limits and the percentage estimate are not reported in the registry record. The endpoint’s denominator is not stated as a count, although the primary analysis population is named as the full analysis set.

The secondary outcomes cover symptom score, bladder-pain visual analogue scale, urinary-urgency visual analogue scale, and quality-of-life visual analogue scale. These may describe distinct aspects of participant experience, but their definitions, numerical results, and relationship to the primary endpoint are not reported in the registry record. The endpoint definition therefore explains what the primary outcome is intended to measure, not whether participants improved or how precisely any observed percentage was estimated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry names a percentage of PGA responders as the primary outcome and specifies a 90% confidence interval. It does not report an outcome estimate, interval limits, a statistical analysis description, or a listed analysis. The concepts below explain how such methods are generally interpreted; they should not be read as confirmation that any particular unreported procedure was used.

What does a responder percentage describe?

In general, a responder percentage is a descriptive summary: it represents the share of participants in a defined analysis population who satisfy a prespecified response rule. Here, that rule uses the PGA improvement categories and adds a second requirement for participants rated slightly improved. A percentage depends on both the number classified as responders and the denominator used. The registry identifies the full analysis set as the primary population, but does not report its size or the responder count. Thus the endpoint can be described conceptually, but the result cannot be reconstructed from the registry record.

Responder definitions turn a graded assessment into a classification. This can make a result easier to interpret as the proportion meeting a specified threshold, but it also means that people with different degrees of change can be grouped together. The additional condition for the slightly improved category is part of the registered definition and should be retained when interpreting any reported responder estimate. The registry does not report how PGA assessments were collected or how missing responses would affect classification.

What would a confidence interval add?

In general, a confidence interval gives a range of values compatible with an estimate under the statistical procedure’s assumptions. A 90% confidence interval is commonly understood through repeated sampling: if the procedure and assumptions were applied across repeated samples, 90% of the resulting intervals would contain the underlying quantity. It is not a statement that there is a 90% probability that a particular fixed value lies in the interval.

For a responder percentage, the interval would help show the precision of the estimate. A narrower interval generally indicates greater precision, while a wider interval indicates more uncertainty. The interval’s width depends on factors including the number of participants contributing to the endpoint and the observed responder proportion, as well as the method used to calculate it. Neither the estimate nor interval bounds are reported in the registry record, so precision cannot be evaluated. The registry’s use of a 90% interval should not be taken as evidence that the estimate is precise or imprecise in the absence of its limits.

How should an observational result be distinguished from a comparison?

In general, a single-group observational outcome describes what was recorded among participants receiving or using the intervention. It does not provide a concurrent counterfactual showing what would have happened to the same participants without the intervention. A randomized comparison can support a different kind of inference because treatment assignment is compared across groups under a defined design. The registry does not report randomization or a comparator; allocation is not stated. Therefore, any primary result, if reported elsewhere, would need to be interpreted according to the observational design rather than as a randomized treatment contrast.

This distinction matters even if a within-group measure changes over time. A change may be clinically relevant to participants, but a single-group before-and-after observation cannot, by itself, determine why the change occurred. General alternatives include natural symptom fluctuation, regression toward typical values after unusually severe symptoms, expectations, and changes in other care. The registry record does not report analyses that address these possibilities.

What can the safety counts establish?

Safety counts report the number of participants affected within a group and the number at risk. The registry lists 1 participant affected by a serious adverse event among 73 at risk and 13 affected by other adverse events among 73 at risk. It lists 0 deaths. These are descriptive counts for the named Cystistat® group. Without a comparator, they do not quantify relative risk against another treatment or against no treatment. The listed serious-event term, pyrexia, has a reported value of 1.4%; the registry does not provide enough detail to infer additional event counts or causal relationships from that term alone.

For adverse-event interpretation, counts of affected participants are distinct from counts of events: an individual could experience more than one event, but the registry summary does not give that detail. The record also does not report event-specific onset, duration, outcome, seriousness criteria, or attribution to the device. General statistical considerations include the limited ability of a study’s observed counts to characterize uncommon outcomes and the uncertainty that accompanies a small number of recorded events. No additional incidence calculation is needed to read the posted counts.

What do the planning assumptions mean?

The registry describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. For time-to-event planning, it identifies total events as the quantity; for other planning, it identifies participants per arm. These are general planning assumptions, not results from the observational study. The registry record does not report a numerical observed effect, the resulting planning estimates, or a trial design using those assumptions. The stated planning approach therefore cannot be treated as the study’s own sample-size justification or as observed power. In particular, a planning illustration cannot replace the study’s actual outcome estimate or establish that an endpoint analysis was conducted.

The registry lists no statistical analyses. The analysis method for the PGA percentage, handling of repeated measurements, any adjustment for baseline values, and any model-based assessment are not reported in the registry record. Statistical explanations describe what methods can mean in general; they do not fill in the missing analysis plan or establish which method was used.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary PGA outcome and four secondary outcomes: a bladder pain or interstitial cystitis symptom score, visual analogue scales for bladder pain and urinary urgency, and a visual analogue scale for quality of life. It reports five outcome measures in total. The registry record does not report a multiplicity strategy, such as a prespecified hierarchy or adjustment across outcomes. In general, when several outcomes are tested, the chance of at least one apparently notable result arising by chance can increase if each is assessed separately. That is a general statistical concern, not a claim about any result in this study. Because no analyses are listed, the effects of any testing strategy cannot be assessed.

Missing-data methods are also not reported in the registry record. The primary population is called the full analysis set, but its definition, size, and handling of participants without a week 12 assessment are not stated. The registry does not describe imputation, complete-case analysis, or sensitivity analyses. Without these details, it is not possible to assess whether missing outcome data could affect the responder percentage or its precision.

Enrollment is 74, while the safety group reports 73 participants at risk. The registry does not explain this difference. It should not be assumed to represent a specific kind of missingness or participant disposition. The numbers do indicate that the enrolled total and the reported safety denominator are not identical; the record does not provide the flow information needed to explain why.

The primary analysis population and the safety population may serve different purposes in general: one can be defined for outcome analysis and another for safety summaries. The registry does not provide enough information to determine how the populations were assembled in this study or how many participants contributed to each outcome. Participant flow, outcome availability, and the treatment of missing assessments are therefore important unreported details.

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 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pyrexia (1.4%).

The registry reports safety information for the group named “Single Arm: Cystistat® 40 mg/50 mL Solution.” It lists 73 participants at risk for serious adverse events, with 1 participant affected. For other adverse events, it also lists 73 at risk, with 13 affected. The record lists 0 deaths. These figures are descriptive counts, not comparisons with another group.

Pyrexia is listed as the top serious adverse-event term, with a reported value of 1.4%. The registry record does not give further detail about this term’s event count, timing, outcome, or relationship to Cystistat®. The serious-event count should not be conflated with the count for other adverse events: the registry presents them in separate categories.

In general, an adverse-event count tells how many participants were recorded as affected under the registry’s summary, but it does not by itself establish cause. The record does not report whether events were judged related to the device, how seriousness was determined, whether one participant experienced multiple events, or how long participants were monitored for safety. No comparative risk can be estimated from the single-group counts. The reported counts should therefore be read as the safety information recorded in the registry, with their limits, rather than as proof of safety or harm.

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

The registry establishes that an observational study was registered to evaluate the performance and safety of Cystistat® in interstitial cystitis or bladder pain syndrome. It also records the definition of a primary PGA responder outcome, the intended assessment period of up to week 12, and the named secondary assessments. The status is completed, and enrollment is reported as 74.

What the record does not establish is the observed percentage of participants who met the PGA response definition. No primary outcome estimate or confidence interval is reported in the registry record. The secondary outcome estimates are also not reported. As a result, the posted record does not quantify symptom, pain, urgency, or quality-of-life changes, nor does it show the statistical precision of any such changes.

The design information does not report a randomized comparator, and allocation is not stated. In general, an observational result can describe outcomes among participants in the study, but a single-group result cannot by itself separate an intervention effect from other explanations for change. The registry’s stated purpose of evaluating performance and safety is not an outcome finding, and the device description is not evidence that the intended performance was achieved.

The safety summary records 1 participant affected by a serious adverse event among 73 at risk, 13 affected by other adverse events among 73 at risk, and 0 deaths. Pyrexia is identified as the top serious adverse-event term at 1.4%. These figures do not provide a comparison with another treatment and do not establish whether any event was caused by the device. Further safety details are not reported in the registry record.

In short, the record is informative about the study’s registered question and a limited set of safety counts, but it does not supply the outcome results needed to determine the size or precision of the measured response. It cannot support a comparative conclusion about treatment effects. These statistical limits do not imply that an unreported outcome was favorable or unfavorable.

13. Why This Trial Matters Statistically

This study is statistically notable for the distinction between an outcome definition and an outcome result. The registry gives a specific PGA responder rule, including the additional condition for participants rated slightly improved. That detail clarifies what the primary endpoint was intended to count. However, the registry record does not report the resulting percentage or its 90% confidence interval. A well-defined endpoint is useful for interpretation, but it cannot answer the study question without the corresponding estimate.

The observational design also shapes the kind of conclusion that can be drawn. The record does not report a randomized comparison, and allocation is not stated. Statistical summaries from a single treatment group describe recorded outcomes in that group; they do not automatically identify what would have happened under a different treatment or without treatment. This is a general design issue rather than a judgment about the intervention.

The safety summary shows why denominators and categories matter. Serious and other adverse events are reported separately, each with 73 participants at risk, while enrollment is 74. The record does not explain the relationship between those totals. It also reports 0 deaths and identifies pyrexia as the top serious adverse-event term at 1.4%. Without further event detail or a comparator, these counts are limited descriptive information rather than a comparative safety analysis.

The statistical record is incomplete for assessing precision, missing data, multiplicity, and analysis populations. The full analysis set is named, but its size and definition are not reported. The analysis methods and results for the primary and secondary outcomes are not listed. These omissions matter because they prevent readers from evaluating how estimates were derived, who contributed to them, and how uncertainty was handled.

The registry record therefore matters as a transparent statement of the intended endpoint and study purpose, while also illustrating that registration details and reported results are different kinds of evidence. The endpoint and safety descriptions can orient readers, but they do not substitute for posted outcome estimates and a clear analysis account.

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.

Several limitations follow directly from the information recorded for this study. The primary outcome’s definition is available, but the outcome estimate and the limits of its 90% confidence interval are not reported in the registry record. The secondary outcome estimates are also absent. Statistical precision and the direction or magnitude of measured change therefore cannot be assessed from the registry entry.

The study is described as observational, and the registry does not report a randomized comparator. Allocation is not stated. This limits the kinds of comparisons that can be supported and leaves no posted control-group outcome against which to interpret the single Cystistat® safety group. The record also does not explain whether any other care or relevant changes during follow-up were documented.

The primary analysis population is identified as the full analysis set, but its size and membership are not reported. Enrollment is 74, whereas the safety summaries list 73 participants at risk; the reason for this difference is not reported in the registry record. No participant-flow details explain outcome availability or follow-up completion. The registry also does not report how missing PGA or secondary assessments were handled.

Analysis methods, multiplicity procedures, and the treatment of repeated assessments are not reported. The registry lists outcome measures but no analyses. It is therefore not possible to evaluate model choices, adjustments, sensitivity checks, or whether the registered endpoint was analyzed as described. The statistical planning assumptions do not provide a numerical planning result or a reported sample-size justification for this study.

Safety interpretation is also constrained by the summary level of detail. The record gives affected-participant counts, but does not describe event timing, duration, attribution, or whether an affected participant experienced multiple events. It does not report additional information about the seriousness assessment or follow-up for adverse events. These gaps limit contextual interpretation without changing the counts that are posted.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Real-world Evidence Study on Cystistat — NCT05544695.
• Registry record last updated 2026-01-09; status last verified 2025-11.
• Results first posted 2026-01-09.
• 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

NCT05544695, “Real-world Evidence Study on Cystistat,” is marked completed. MEDA Pharma GmbH & Co. KG is listed as sponsor. The registry reports enrollment of 74, a start date of 2022-10-21, and a primary completion date of 2024-07-29. The study concerns interstitial cystitis and bladder pain syndrome and lists intravesical sodium hyaluronate (Cystistat®) as the intervention.

The primary endpoint is the percentage of PGA responders up to week 12, with a 90% confidence interval specified. The primary analysis population is the full analysis set. The registry record does not report the primary or secondary outcome estimates and lists no analyses. Safety information records 1 participant affected by a serious adverse event among 73 at risk, 13 affected by other adverse events among 73 at risk, and 0 deaths. Pyrexia is listed as the top serious adverse-event term at 1.4%.

The record does not report a randomized comparator, the reason enrollment and safety counts differ, or detailed statistical and missing-data methods. The posted information describes the study question and limited safety counts but does not establish a comparative outcome.