This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for PROPPER Prospective Registry of Outcomes With Penile Prosthesis (NCT01383018), a registered phase not stated study. The primary outcome is Number of Participants With Penile Prosthesis Overall Subject Satisfaction.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01383018 |
| Phase | Phase not stated |
| Condition | Erectile Dysfunction, Impotence |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 1457 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Scientific Corporation |
| Results posted | Yes |
2. Clinical Question
Population
Men with erectile dysfunction undergoing penile implant surgery are the broad population of interest. The primary endpoint applies more narrowly to subjects who received an AMS penile prosthesis and completed the 1 year follow-up visit. The registry enrolled 1457 participants, but the number who completed that visit is not reported in the registry record.
Intervention
The intervention is an AMS penile prosthesis device. The arm description refers to men for whom an AMS penile prosthesis is recommended, while the primary endpoint population is defined by actually receiving an AMS device and completing follow-up.
Comparator
No like-for-like control comparison is described. Allocation is not stated, and the record does not identify a comparison group that did not receive an AMS penile prosthesis. The registry evaluates outcomes overall and by penile prosthesis, but comparative results are not reported in the registry record.
Primary question
Among subjects who received an AMS penile prosthesis and completed the 1 year follow-up visit, how many reported overall subject satisfaction? Satisfaction was assessed with a non-validated standard question. The primary endpoint description does not supply the observed count or the number assessed, so the proportion satisfied and its precision cannot be established from the registry record.
PROPPER is an observational registry intended to collect and better understand real-world outcomes for men undergoing penile implant surgery to treat erectile dysfunction. Its question is descriptive rather than a randomized treatment comparison: it concerns satisfaction among the specified recipients who completed follow-up. The record also describes evaluation by penile prosthesis, but it does not report the results for individual devices or explain how those evaluations were compared. The registry includes 11 outcome measures, while the recorded number of analyses is 0. Neither the registry purpose nor the endpoint description establishes whether satisfaction was assessed in every enrolled participant; the primary endpoint population is specifically restricted to recipients with a completed follow-up visit.
3. Trial Design
PROPPER (NCT01383018) is a prospective observational registry sponsored by Boston Scientific Corporation. Its stated purpose is to collect and better understand real-world outcomes for men undergoing penile implant surgery to treat erectile dysfunction. The registry record lists an enrollment of 1457 and a completed status. The recorded start date is 2011-06-13, and the primary completion date is 2017-11-30.
The intervention is listed as AMS Penile Prosthesis Devices, a device intervention. The arm description refers to men for whom an AMS penile prosthesis is recommended. The primary endpoint, however, is defined among subjects who received an AMS penile prosthesis and completed the 1 year follow-up visit. The distinction matters: recommendation and receipt are not identical eligibility descriptions, and completion of follow-up further narrows the endpoint population. The count satisfying all of those conditions is not reported in the registry record.
This is not a randomized comparison. Allocation is not stated, and the listed arm is not a like-for-like control comparison. The record does not identify a concurrent untreated or alternative-treatment control group. Therefore, the registry design supports describing the recorded experiences of device recipients, but the details do not establish a causal comparison between treatment strategies.
The primary outcome is one of 11 outcome measures. The recorded number of analyses is 0. That registry entry does not give a numerical result for the primary outcome, an analysis plan, or details of how the question was administered. Sample-size planning assumptions described for hypothetical comparisons are planning illustrations, not evidence that this registry was designed as a two-arm trial. The registry's own sample-size justification is 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.
Overall Study
| Stage | AMS Penile Prosthesis Recipients |
|---|---|
| STARTED | 1457 |
| COMPLETED | 1082 |
| NOT COMPLETED | 375 |
Reasons for not completing this period:
| Reason | AMS Penile Prosthesis Recipients |
|---|---|
| Adverse Event | 14 |
| Death | 10 |
| Lost to Follow-up | 5 |
| Physician Decision | 5 |
| Withdrawal by Subject | 9 |
| Subject not implanted | 76 |
| Missed Visit | 247 |
| Site closed early-not compliance related | 7 |
| Patient moved away from site | 1 |
| Subject Incarcerated | 1 |
Analysis population for the primary outcome, as defined in the registry: Subjects who received an AMS penile prosthesis and completed 1 year follow-up visit.
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: AMS penile prosthesis recipients that completed baseline assessments. Subjects that started the study but did not have implantation are not included.
| Characteristic | Unit | AMS Penile Prosthesis Recipients |
|---|---|---|
| Participants analysed | 1380 | |
| Age, Continuous | years | 63.8 (SD 9.7) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 1380 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 77 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 1303 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 3 |
| Race (NIH/OMB): Asian | Participants | 15 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 3 |
| Race (NIH/OMB): Black or African American | Participants | 187 |
| Race (NIH/OMB): White | Participants | 1152 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 20 |
| Primary ED etiology: Radical prostatectomy (RP) | Participants | 369 |
| Primary ED etiology: Diabetes | Participants | 283 |
| Primary ED etiology: Cardiovascular disease | Participants | 251 |
| Primary ED etiology: Peyronies disease | Participants | 123 |
| Primary ED etiology: Priaprism | Participants | 19 |
| Primary ED etiology: Other | Participants | 335 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Penile Prosthesis Overall Subject Satisfaction, measured over 1 year, post-implantation.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with penile prosthesis overall subject satisfaction at 1 year, post-implantation. It is defined for subjects who received an AMS penile prosthesis and completed the 1 year follow-up visit. Satisfaction was measured using a non-validated, standard question, with the stated objective of assessing effectiveness overall and by penile prosthesis.
A participant count is a binary-outcome summary: each person is classified according to whether the endpoint is met, and the count records how many meet it. In general, such a count is easiest to interpret when read alongside the number of people assessed. That denominator is necessary to understand how common the outcome was in the assessed group. The registry record does not report either the satisfaction count or the number completing the primary endpoint assessment, so a satisfaction proportion cannot be stated.
The endpoint is used because participant-reported satisfaction captures an aspect of the experience that is not identical to a device or clinical event. However, the registry describes the question as non-validated and does not report its wording, response options, handling of uncertain responses, or measurement properties. The endpoint therefore has limits as a standardized measure, and its result cannot be interpreted more precisely than the recorded definition and data allow. Results by penile prosthesis are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a prospective observational assessment of real-world outcomes after penile implant surgery. Its primary endpoint asks for the number of eligible participants reporting overall subject satisfaction at 1 year after implantation. The endpoint population is not all 1457 enrolled participants: it consists of subjects who received an AMS penile prosthesis and completed the 1 year follow-up visit. The number in that population is not reported in the registry record.
Most importantly, no observed satisfaction count, denominator, proportion, confidence interval, or statistical test is included in the available registry entries. Thus, the primary outcome's magnitude and precision cannot be characterized. The outcome title and its measurement description establish what was intended to be counted, not what the observed result was. No conclusion about the level of satisfaction among participants can be drawn from the title alone.
The registry says that satisfaction was assessed overall and by penile prosthesis. It does not report device-specific results or a comparative estimate. Because allocation is not stated and the registry is not a randomized comparison, any differences among device groups, if reported elsewhere, would need to be interpreted in light of how patients and devices were selected. The registry entries do not establish that such groups were comparable in characteristics or follow-up.
The safety summary gives counts for the AMS Penile Prosthesis Receipients group: 1380 at risk for serious events, 36 affected by serious events, 1380 at risk for other adverse events, and 72 affected by other adverse events. It also lists 44 deaths. These are descriptive counts in the registry summary; they do not, by themselves, identify the cause of an event or establish that a device caused it. The record lists serious-event terms and percentages, but the denominator and event-attribution details for those percentages are not reported in the registry record.
In general, a confidence interval communicates uncertainty around an estimate, while a hypothesis test addresses compatibility with a specified null model under stated assumptions. Neither can be interpreted for the primary satisfaction endpoint because no estimate or analysis result is reported. The registry lists 11 outcome measures and 0 analyses. That information does not establish what analyses were planned, whether any analyses were performed outside the registry entry, or how missing follow-up affected the endpoint. Overall, the record supports a description of the registry's question and the posted safety counts, but not a numerical assessment of satisfaction or a comparative treatment effect.
9. Statistical Methods Explained
The registry's primary endpoint is a participant count for an outcome that can be classified as present or absent: overall subject satisfaction. The target population is subjects who received an AMS penile prosthesis and completed 1 year follow-up. The registry describes measurement with a non-validated, standard question. It does not report the question wording, the rules used to classify responses, or the number of participants who completed the assessment. No numerical primary-outcome result is reported in the registry record.
What does a participant count tell us?
A count tells readers how many participants met an endpoint in the specified group. In general, a count alone is difficult to compare across groups of different sizes. A proportion uses the number assessed as its denominator and can describe the share meeting the endpoint. Uncertainty around that proportion can be described with a confidence interval. These are general statistical concepts; no satisfaction proportion or confidence interval can be stated from the registry entries because the endpoint count and assessed population are not reported.
What is the role of the registry design?
Prospective data collection means the registry was organized to collect outcome information as participants were followed, rather than being described as a randomized treatment assignment. The record identifies the project as observational and does not state allocation. In general, observational outcomes can describe what was recorded among participants but do not alone isolate the effect of an intervention from differences in participant characteristics, clinical choices, follow-up, or other influences. The listed arm is not a like-for-like control comparison, so a causal contrast is not supported by the design details presented.
The primary endpoint's follow-up definition also shapes interpretation. It concerns participants who both received the device and completed the specified follow-up. In general, an analysis restricted to people with completed follow-up can differ from an analysis of everyone enrolled if follow-up completion is related to outcomes or participant characteristics. The registry record does not report the number completing follow-up, reasons for missing assessments, or a method for handling missing data. The extent and direction of any resulting bias therefore cannot be assessed.
How should the safety counts be read?
The record lists 1380 participants at risk for serious adverse events and 36 affected, as well as 1380 at risk for other adverse events and 72 affected. It also lists 44 deaths. These are count summaries. In general, counts should be interpreted with their population definitions and event ascertainment rules; counts do not establish that an event was caused by a device. The available details do not report event-level follow-up time, attribution, or further definitions for these categories. The serious-event terms are accompanied by percentages, but the denominator basis is not reported in the registry record.
What do the planning assumptions mean?
The sample-size assumptions describe a planning illustration based on an observed effect, not the registry's own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For time-to-event illustrations, the stated output is the total number of events using the Schoenfeld method; other illustrations are expressed as participants per arm. These assumptions do not describe an observed analysis or establish the sample-size justification for PROPPER, which is not reported in the registry record. Planning sample sizes are illustrations of what a hypothetical study might require under stated assumptions, not observed power. No observed effect estimate for the primary endpoint is available in the registry entries, so no planning estimate can be reconstructed from them.
Finally, the registry lists 11 outcome measures and 0 analyses. In general, when multiple outcomes or comparisons are examined, multiplicity can affect the interpretation of statistical evidence and may require a prespecified strategy. The record does not state whether, or how, multiplicity was addressed. It also does not report a statistical analysis plan, confidence intervals, hypothesis tests, or an analysis population beyond the endpoint definition. Those elements should not be inferred from the registry's endpoint name or from hypothetical planning assumptions.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 11 outcome measures and 0 analyses. The primary outcome is one measure within that registry record, but the available details do not specify which outcomes were designated as primary or secondary beyond the satisfaction endpoint description, or how any analyses were prioritized. The registry's approach to multiplicity is not reported in the registry record.
In general, testing several outcomes or comparisons can increase the chance that at least one result appears statistically notable by chance. Researchers may address this with prespecified outcome hierarchies or adjustment methods, but the record does not identify such a strategy. The existence of 11 outcome measures does not, by itself, show that 11 statistical tests were performed; the recorded number of analyses is 0. Details of analyses outside that registry entry are not reported.
The primary endpoint population requires receipt of an AMS penile prosthesis and completion of the 1 year follow-up visit. The number who met this definition is not reported in the registry record. The number missing the satisfaction assessment, reasons for missingness, and methods for handling missing data are also not reported. In general, missing outcomes may affect estimates if the participants with observed results differ systematically from those without them. Without the completion count or missing-data approach, the extent of this concern cannot be determined.
The analysis population beyond the endpoint definition is not reported in the registry record. It is not stated whether all enrolled participants, only device recipients, or another prespecified group was intended for any analysis. The record also does not report a statistical analysis plan or explain how participants with incomplete follow-up, incomplete responses, or other missing information were treated. Consequently, the scope and reproducibility of the planned statistical analyses cannot be evaluated from these details.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| AMS Penile Prosthesis Receipients | 36 | 1380 | 2.6% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| AMS Penile Prosthesis Receipients | 44 of 1380 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| AMS Penile Prosthesis Receipients | 72 of 1380 |
Most frequent serious adverse event terms
| Event term | Organ system | AMS Penile Prosthesis Receipients |
|---|---|---|
| Device Infection | Infections and infestations | 11 of 1380 |
| Erosion | Injury, poisoning and procedural complications | 6 of 1380 |
| Reservoir Herniation | Injury, poisoning and procedural complications | 3 of 1380 |
| Abscess | Infections and infestations | 2 of 1380 |
| Hematoma | Injury, poisoning and procedural complications | 2 of 1380 |
| Urinary Retention | Renal and urinary disorders | 2 of 1380 |
| Pain/Discomfort | Injury, poisoning and procedural complications | 1 of 1380 |
| Cardiac Event - Non-specific | Vascular disorders | 1 of 1380 |
| Cellulitis | Infections and infestations | 1 of 1380 |
| Cylinder Crossover | Injury, poisoning and procedural complications | 1 of 1380 |
Most frequent non-serious adverse event terms
| Event term | Organ system | AMS Penile Prosthesis Receipients |
|---|---|---|
| Device Infection | Infections and infestations | 5 of 1380 |
| Erosion | Injury, poisoning and procedural complications | 5 of 1380 |
| Reservoir Herniation | Injury, poisoning and procedural complications | 4 of 1380 |
| Superficial Wound Infection | Infections and infestations | 4 of 1380 |
| Urinary Retention | Injury, poisoning and procedural complications | 3 of 1380 |
| Device Cylinder Aneurysm/Bulge | Product Issues | 3 of 1380 |
| Urethral Trauma | Injury, poisoning and procedural complications | 3 of 1380 |
| Urinary Retention | Renal and urinary disorders | 3 of 1380 |
| Pain/Discomfort | General disorders | 2 of 1380 |
| Extrusion | Injury, poisoning and procedural complications | 2 of 1380 |
Serious events with the highest arm-level rate: device infection (0.8%), erosion (0.4%), reservoir herniation (0.2%), abscess (0.1%), hematoma (0.1%).
The adverse-event summary lists 1380 participants at risk for serious adverse events, with 36 affected. It separately lists 1380 at risk for other adverse events, with 72 affected. The record also lists 44 deaths for the AMS Penile Prosthesis Receipients group. These figures are descriptive counts; they should not be read as proof that the device caused an event or death.
The leading serious-event terms are Device Infection (0.8%), Erosion (0.4%), Reservoir Herniation (0.2%), Abscess (0.1%), Hematoma (0.1%), and Urinary Retention (0.1%). The registry entries do not explain the denominator used for these percentages, the attribution of events to the device, or whether participants could contribute more than one event. Percentages and counts therefore should not be treated as interchangeable summaries of a clearly defined risk without those definitions.
In general, adverse-event counts depend on how events were defined, monitored, and recorded, as well as on the population and follow-up period. The available summary does not report those details sufficiently to characterize event timing or person-time. The counts describe what the registry lists; they do not establish comparative safety against another treatment because no like-for-like control comparison is identified.
12. What the Result Does, and Does Not, Mean
The registry record establishes that PROPPER was a prospective observational registry intended to collect real-world outcomes among men undergoing penile implant surgery for erectile dysfunction. It identifies overall subject satisfaction at 1 year as the primary endpoint and defines the endpoint population as subjects who received an AMS penile prosthesis and completed the follow-up visit. It also describes the satisfaction question as non-validated and standard.
Those details explain what the registry set out to measure, but they do not provide the observed satisfaction count or the number assessed. Without those values, the level of satisfaction, its proportion in the endpoint population, and the precision of an estimate cannot be stated. The endpoint title should not be mistaken for a reported result.
The registry's observational design also sets limits on causal interpretation. No randomized allocation or like-for-like control comparison is described, and allocation is not stated. The record therefore does not support attributing any outcome to the device by comparing it with an alternative treatment. Nor does the available information establish whether results differ across penile prostheses, despite the endpoint description's reference to evaluation by device.
The safety summary reports event counts and a list of serious-event terms. These summaries describe recorded events in the registry group, but do not establish causation, comparative risk, or the event rate over a defined duration. The basis for the percentages attached to serious-event terms is not reported in the registry record.
In general, statistical interpretation depends on knowing who was assessed, how outcomes were measured, and how uncertainty and missing data were handled. Here, the follow-up completion count, missing-data methods, and statistical analysis plan are not reported. The most defensible reading is therefore descriptive: the registry's purpose, target endpoint, and listed safety summaries can be identified, but a numerical conclusion about the primary satisfaction outcome or a comparative treatment effect cannot be drawn from the registry entries.
13. Why This Trial Matters Statistically
PROPPER is statistically informative as an example of how a prospective registry can frame a real-world outcomes question without being a randomized trial. The record identifies an intended participant-reported endpoint at a defined follow-up point and names the population to which that endpoint applies. These details make clear that the central quantity of interest is satisfaction among recipients who completed follow-up, rather than a count across every enrolled participant.
The record also illustrates why endpoint definitions and results must be distinguished. A precise outcome title and timeframe do not supply an observed count, denominator, or estimate. For a participant-count endpoint, knowing how many people were assessed is central to interpreting how common an outcome was. The registry entries do not report the satisfaction result or the number completing the endpoint assessment, so the main clinical question cannot be answered numerically.
Observational registries can capture outcomes in routine practice, but interpretation depends on how participants entered the registry, how devices were selected, and whether follow-up was complete. The record does not state allocation and does not describe a like-for-like control. This makes the registry useful for understanding what outcomes were intended to be collected, while limiting causal comparisons based on the information reported.
Finally, the separation between registry planning assumptions and the registry's actual design is important. The sample-size assumptions describe a hypothetical planning illustration with two-arm allocation and a specified significance level; they are not evidence of the registry's own design or an observed-power calculation. The registry's sample-size justification and analysis plan are not reported. This distinction helps prevent hypothetical planning calculations from being interpreted as results of the observational registry.
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 primary limitation for interpreting the main outcome is that the registry entries do not report the observed satisfaction count or the number of participants assessed at 1 year. The target population is restricted to subjects who received an AMS penile prosthesis and completed follow-up, but the size of that population is not reported. Consequently, no satisfaction proportion or precision estimate can be described.
The satisfaction measure is described as a non-validated, standard question. The wording, response options, administration procedures, and rules for classifying a response as satisfaction are not reported in the registry record. The measure's reproducibility and interpretation therefore cannot be evaluated from the available description.
The study is observational, allocation is not stated, and no like-for-like control comparison is identified. The registry does not report how device selection occurred or whether groups differed in relevant characteristics. Results by penile prosthesis are not reported in the registry record, so the stated device-level evaluation cannot be assessed.
Follow-up completeness and missing-data handling are not reported. The record also does not provide the statistical analysis plan, confidence intervals, or inferential results for the primary endpoint. Although 11 outcome measures are listed, the multiplicity approach is not reported, and the record lists 0 analyses. These registry entries do not establish what analyses may have been conducted outside the registry entry.
For safety, the summary provides participant counts and serious-event percentages, but the percentage denominator, event attribution, event timing, and follow-up exposure details are not reported. The listed deaths and adverse events are therefore descriptive and cannot establish causation or comparative safety. These limitations constrain interpretation of both the principal endpoint and the safety summaries.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: PROPPER Prospective Registry of Outcomes With Penile Prosthesis — NCT01383018.
- Registry record last updated 2021-02-12; status last verified 2021-01.
- Results first posted 2020-02-18.
- 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.
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18. Record Summary
PROPPER (NCT01383018) is a completed prospective observational registry sponsored by Boston Scientific Corporation. Its stated purpose was to collect and better understand real-world outcomes for men undergoing penile implant surgery to treat erectile dysfunction. Enrollment was 1457; the recorded start date was 2011-06-13, and primary completion was 2017-11-30.
The intervention is AMS Penile Prosthesis Devices. The primary endpoint is the number of participants with overall subject satisfaction at 1 year after implantation, measured with a non-validated standard question among recipients who completed follow-up. The numerical satisfaction result and endpoint denominator are not reported in the registry record. The registry lists 11 outcome measures and 0 analyses.
The adverse-event summary lists 1380 at risk and 36 affected for serious events, 1380 at risk and 72 affected for other events, and 44 deaths. Serious-event terms and percentages are also listed, but the percentage denominator is not reported in the registry record. No randomized or like-for-like control comparison is identified.