Embosphere® PROstate Post Market Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Embosphere® PROstate Post Market Study (NCT03527589), a registered phase not stated study. The primary outcome is Long-term Effectiveness of Prostatic Artery Embolization (PAE) With Embosphere Microspheres as Assessed by the International Prostate Symptom Score (IPSS)..

2. Clinical Question

3. Trial Design

This was a prospective post-market study of prostatic artery embolization using Embosphere Microspheres. Its stated goal was to evaluate long-term safety and effectiveness in a real-world setting among patients with lower urinary tract symptoms due to benign prostatic hyperplasia. The registry record lists enrollment of 499 and a completed status. The recorded start date is 2018-08-16, and the primary completion date is 2020-01-21.

The intervention was prostate artery embolization. Embolic size was left to investigator discretion. The record describes a treated group, but does not describe a comparator group or state the allocation method. It is not a randomized comparison, and the arms are not a like-for-like control comparison. Consequently, this design description does not establish a basis for attributing any change over time specifically to the intervention rather than to other influences.

The primary measure is the International Prostate Symptom Score (IPSS) at 12 months, analyzed as a change from baseline for paired observations. The registry record also lists outcomes involving IPSS after discontinuation of an indwelling bladder catheter, urinary-symptom quality of life, device- or procedure-related adverse events, catheter removal, technical success, additional treatment for recurrent or refractory symptoms, and erectile function measured with the Sexual Health Inventory for Men. The record lists eight outcome measures and zero analyses.

The registry record does not report a sample-size justification, a detailed statistical analysis plan, interim analyses, or the analysis population. The information about planning illustrations describes general assumptions—two-sided significance level 0.05, equal allocation between two arms, and a normal approximation—but these are not identified as the trial’s own design. The number of participants enrolled and the safety population at risk should not be treated as interchangeable: the record lists 499 enrolled and 487 at risk for the reported adverse-event group, without explaining that difference.

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 Long-term Effectiveness of Prostatic Artery Embolization (PAE) With Embosphere Microspheres as Assessed by the International Prostate Symptom Score (IPSS)., measured over 12 Months.

The primary endpoint is the mean change in International Prostate Symptom Score from baseline to 12 months after prostate artery embolization. The calculation is defined for paired data: participants must have an available score at both baseline and 12 months to contribute to that change measure. IPSS is a seven-question measure whose item scores are summed to produce a total from 0 to 35. Lower scores represent better outcomes and higher scores represent worse outcomes; under the registry’s definition, a negative change means improvement.

A symptom score gives a quantitative way to describe the level of urinary symptoms and how the score changes over time. Reporting a mean change describes the average change among the paired observations, while a 95% confidence interval communicates uncertainty around that estimate. Neither quantity is reported in the registry record for this endpoint. Thus, the endpoint definition is available, but the size and precision of the observed change are not.

The endpoint is labeled long-term effectiveness, while its specified assessment time is 12 months. The registry record does not provide further time points for this primary endpoint. It also does not report the number of participants with paired baseline and 12-month IPSS data, so the size of the analysis population cannot be established from the endpoint description.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a continuous measure: the total IPSS score and its change over time. A mean summarizes the center of a set of numerical observations by averaging them. For this endpoint, the registry defines the change as the 12-month mean IPSS minus the baseline mean IPSS for paired data, specifically data available at both time points. The record also defines a negative change as improvement because lower IPSS scores represent better outcomes. These conventions determine how an estimate would be read, but the estimate itself is not reported in the registry record.

What does paired data mean?

In a paired analysis, each participant’s observations at the two time points are linked. The analysis concerns within-participant change rather than treating the baseline and follow-up observations as unrelated groups. Pairing can account for stable differences between participants, because each person serves as their own reference for change. It also means that a participant needs usable observations at both time points to contribute to the change calculation. The registry record does not report how many participants had paired IPSS data or how missing observations were handled.

What does a 95% confidence interval describe?

General statistical explanation: a confidence interval expresses the uncertainty associated with an estimate under a specified statistical procedure. It is not a guarantee that the true value lies within a particular calculated interval, and it does not by itself establish whether a change is important. Its width reflects precision: wider intervals indicate greater uncertainty than narrower intervals, all else equal. The endpoint specifies a 95% confidence interval, but neither its limits nor the underlying mean change are reported in the registry record. Therefore, the precision of the primary result cannot be assessed from the posted endpoint information.

How should a before-and-after result be interpreted?

General statistical explanation: observing a change between baseline and follow-up describes change over time in the people measured. A concurrent comparator can help distinguish changes associated with an intervention from changes that may occur for other reasons, depending on the design and analysis. This study description does not identify a comparator arm or a randomized comparison. Thus, even if a baseline-to-follow-up estimate were available, the design information would support describing the observed change, not treating it as a controlled comparison of treatment effects.

What can adverse-event counts tell readers?

Adverse-event counts describe events or affected participants recorded in a defined group. Their interpretation depends on the denominator, the event definitions, and the observation period. The record gives 487 at risk for the treated group, along with counts for serious events, other events, and deaths. It does not provide a comparative group in the trial description. General statistical explanation: counts without a comparator can characterize what was recorded in the observed group, but cannot establish how those counts differ from what would have occurred under another treatment or no intervention.

What are the planning assumptions?

The planning-illustration assumptions are described as a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. These assumptions describe an illustration, not the trial’s own design or sample-size justification. They should not be interpreted as observed power. The trial description identifies a treated group and does not describe a randomized two-arm comparison. The registry record does not report the trial’s sample-size justification, and no numerical planning estimate is stated in the registry record.

General statistical explanation: power is a design property under specified assumptions about the effect, variability, significance threshold, and analysis. A planning calculation can illustrate how sample size relates to those assumptions, but it does not indicate the probability that a completed study has produced a true or clinically meaningful result. In particular, a calculation based on an observed effect is not an independent confirmation of that effect. The registry record does not report sufficient primary-outcome results to evaluate the effect or its uncertainty.

The registry record lists zero analyses. It does not report the statistical tests or models used, how confidence intervals were calculated, whether any adjustment was made, or which analysis populations were used. It also does not report interim analyses. These details should not be inferred from the endpoint definition or from general statistical conventions.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists eight outcome measures, including the primary IPSS endpoint and secondary outcomes covering symptom scores, urinary-symptom quality of life, adverse events, catheter removal, technical success, additional treatment, and erectile function. It lists zero analyses. A list of outcomes does not establish which outcomes were ultimately analyzed, whether all results were reported, or how the analyses were prioritized.

When a study evaluates multiple outcomes or performs multiple statistical tests, the chance of finding at least one apparently unusual result can increase. General statistical explanation: multiplicity procedures are sometimes used to control that risk, but the appropriate approach depends on the planned questions and analysis strategy. The registry record does not report whether multiplicity was considered or adjusted for. It also does not report a detailed statistical analysis plan, so the planned hierarchy among outcomes and any pre-specified testing procedure are not available in the registry record.

The primary endpoint requires paired baseline and 12-month IPSS data. The number of participants with those paired observations is not reported in the registry record. The record does not describe missing-data methods, reasons for missing observations, or assumptions about the missingness process. It also does not identify the analysis population, such as which participants were included in each outcome analysis. Therefore, the enrollment figure alone cannot be used to establish the number analyzed for the primary endpoint or secondary outcomes.

The record lists enrollment of 499 and an adverse-event group with 487 at risk. It does not explain why these figures differ. No reason for that difference, or its relationship to outcome availability, should be inferred. Without outcome-specific denominators and analysis-population definitions, readers cannot assess how much the reported results—where available—might depend on missing data or participant inclusion decisions.

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: acute renal failure (0.2%), blood in urine (0.2%), dizziness upon walking (0.2%), dyspnea and congestive heart failure (0.2%), emergency admission with abdominal pain and vomiting (0.2%).

For the treated group, the registry record lists 487 participants at risk for adverse events. It records 10 affected by serious adverse events, 57 affected by other adverse events, and 0 deaths. The record also lists six serious adverse-event terms, each reported at 0.2%: acute renal failure; blood in urine; dizziness upon walking; dyspnea and congestive heart failure; emergency admission with abdominal pain and vomiting; and false aneurysm at point of puncture.

These figures are descriptive safety information for the treated group. The registry record does not describe a comparator group, so the counts do not establish how safety outcomes compare with another treatment or with no intervention. The listed terms are event categories; the available information does not report whether categories overlap within participants, the detailed event narratives, or outcome-specific follow-up duration. The record does not explain the difference between 499 enrolled and 487 at risk. The counts should therefore be read with their stated denominator and without assuming a reason for that difference.

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

The registry record describes a prospective post-market study of prostate artery embolization with Embosphere Microspheres in patients with lower urinary tract symptoms due to benign prostatic hyperplasia. It gives a clear definition for the primary endpoint: paired change in total IPSS from baseline to 12 months, with negative change defined as improvement. It also provides descriptive safety counts for the treated group and names several serious adverse-event categories.

However, the primary mean change and its 95% confidence interval are not reported in the registry record. Consequently, the posted information does not establish the direction or size of the average 12-month IPSS change, or how precisely it was estimated. No conclusion about statistical significance or clinical importance can be drawn from the endpoint definition alone. The record also does not report how many participants contributed paired observations.

The study description does not identify a comparator or randomized comparison. A change from baseline, if reported, would describe a change among the observed participants over time; it would not by itself isolate the effect of the procedure from other influences. The safety counts likewise describe the treated group and do not provide a comparative safety estimate.

The record lists 499 enrolled, 487 at risk in the adverse-event group, and zero analyses. It does not explain the difference between enrollment and the adverse-event denominator, state the analysis populations, or describe missing-data methods. The registry record therefore documents the study’s intent, intervention, outcome definitions, and some safety information, while leaving the primary effectiveness result and several key analytical details unreported.

13. Why This Trial Matters Statistically

This study illustrates why endpoint definitions and endpoint results need to be distinguished. The registry record specifies the IPSS scale, the baseline-to-12-month comparison, the paired-data requirement, and the direction that represents improvement. Those details make the intended measure understandable. But without the mean change and confidence interval, readers cannot learn the observed magnitude or precision of the primary result. A well-defined outcome is not a substitute for a reported estimate.

The design also matters to the type of conclusion a study can support. The record describes a treated group and does not identify a comparator or randomized comparison. If change over time is reported, it can describe the observed experience of participants, but it cannot alone distinguish the procedure’s contribution from other explanations for change. This distinction is central when interpreting post-market evidence intended to reflect real-world use.

The safety information offers another useful statistical lesson: a denominator and event definitions are necessary context for counts. The record states the group at risk and the counts of serious events, other events, and deaths, but does not provide a comparative group or explain the difference between enrollment and the safety denominator. These details limit what can be inferred from the counts.

Finally, the record lists multiple outcomes but zero analyses, and it does not report multiplicity methods, missing-data handling, or analysis populations. These omissions make it difficult to assess the completeness and robustness of the outcome evidence. The trial is statistically informative as an example of how a registry can document study structure and measurement while leaving important result and analysis details unreported.

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.

A central limitation of the registry record is that it defines the primary endpoint but does not report the primary mean change or its 95% confidence interval. The paired-data denominator is also not reported. Readers therefore cannot assess the magnitude, direction, or precision of the primary endpoint from the record.

The study description identifies a treated group without a comparator and does not state an allocation method. The record explicitly does not describe a randomized comparison, and the arms are not a like-for-like control comparison. Any change over time would therefore be difficult to separate from other influences on participants’ scores. This is a limitation of the design for making comparative treatment-effect claims, rather than a flaw in the definition of the score itself.

The record lists enrollment of 499, while 487 were at risk in the adverse-event group, but does not explain the difference. It also does not report outcome-specific denominators, reasons for missing data, missing-data methods, or analysis populations. Because the primary endpoint requires paired observations, these omissions limit assessment of who contributed to the primary estimate.

Although eight outcome measures are listed, the record lists zero analyses. It does not report a detailed statistical analysis plan, multiplicity handling, interim analyses, or the sample-size justification. Embolic size was determined at investigator discretion, but the record does not give more detail about how that decision was made. The primary endpoint timeframe is 12 months; further primary-outcome follow-up times are not reported in the registry record. These limitations leave important questions about analysis, completeness, and interpretation unanswered.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Embosphere® PROstate Post Market Study — NCT03527589.
• Registry record last updated 2023-12-18; status last verified 2023-12.
• Results first posted 2023-12-18.
• 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

NCT03527589 is a completed prospective post-market study of prostate artery embolization with Embosphere Microspheres for patients with lower urinary tract symptoms due to benign prostatic hyperplasia. The registry record lists enrollment of 499, a start date of 2018-08-16, and a primary completion date of 2020-01-21. Embolic size was determined at investigator discretion.

The primary outcome is paired change in IPSS from baseline to 12 months; a negative change is defined as improvement. The mean change and 95% confidence interval are not reported in the registry record. The record lists eight outcome measures and zero analyses, and does not describe a comparator or randomized comparison.

For the treated group, 487 were at risk for adverse events; 10 were affected by serious adverse events, 57 by other adverse events, and 0 deaths were recorded. The registry record does not explain the difference between enrollment and the safety denominator or report detailed missing-data and analysis-population methods.