Preliminary Performance Study of the New TIPI Device in the Prevention of Stress Urinary Incontinence: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Preliminary Performance Study of the New TIPI Device in the Prevention of Stress Urinary Incontinence (NCT01770691), a na na study. The primary outcome is Mean Percentage of Pad Weight Gain (PWG) Change.

2. Clinical Question

The study’s stated purpose was to evaluate performance of new TIPI designs for temporary management of SUI. The background describes SUI as urine loss associated with increased abdominal pressure, including during activities such as coughing, laughing, sneezing, running, lifting, or walking. The study description says participants performed predefined activities and consumed a certain amount of liquid during baseline testing; the specific activities and amount are not reported in the registry record.

The question is therefore about a measured change in pad weight under the study’s testing conditions. It is not a randomized comparison of a device group against a concurrent untreated group, and the registry record does not describe a comparison between individual designs. It also does not report how many participants used each design or the results for any particular design. The endpoint description includes device use with pads for up to 8 hours and comparisons with baseline average PWG. Without reported outcome values, the magnitude and precision of any observed change cannot be assessed from the registry record.

3. Trial Design

NCT01770691 is listed as a completed, single-group device study sponsored by Assuta Hospital Systems. The recorded enrollment is 7. The registry lists the study phase and allocation as NA and masking as none. Its title identifies the aim as a preliminary performance study of the new TIPI device in the prevention of stress urinary incontinence; the brief summary describes the device as a conservative, disposable treatment for temporary management of SUI.

Each subject was to use different slightly modified designs of the TIPI vaginal pessary. The record explicitly notes that not all subjects would use all SMDs. The intervention listing also names the cleared TIPI (G3) in the endpoint description. The registry does not report the number of designs, the sequence in which subjects used them, or how exposure to each design was assigned. Those details are not reported in the registry record.

The primary endpoint description specifies a 3-day baseline pad period. Participants wore pre-weighed pads for 8 hours a day, performed predefined physical activities, and drank a certain amount of liquid daily. Pads were collected and weighed in the clinic to establish baseline urine leakage. Participants then used SMDs or the cleared TIPI (G3) with pads for up to 8 hours. Device-use average PWG was compared with baseline average PWG and presented as a percentage.

The registry records a study start of 2007-09 and primary completion of 2009-06. It does not describe a concurrent control arm, randomization, masking, or a between-group allocation procedure. A single-group baseline comparison can describe change relative to participants’ own baseline measurements, but it does not by itself separate device-associated change from other influences over time or testing conditions. Additional protocol details, including any sample-size justification or planned interim analyses, are 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

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 Mean Percentage of Pad Weight Gain (PWG) Change, measured over up to 8 hours of use.

The primary endpoint is the mean percentage change in pad weight gain (PWG). PWG is the weight gained by a pad during the measurement period and is used in this study as an indicator of urine leakage. The endpoint description compares average PWG during device use with average PWG during the baseline period without the device. It describes the result as a percentage and names the endpoint as mean percentage of PWG change.

Baseline measurement followed a 3-day pad period, with pre-weighed pads worn for 8 hours a day. Participants were asked to perform predefined physical activities and drink a certain amount of liquid daily. After baseline, participants used a TIPI design with pads for up to 8 hours. The registry’s stated endpoint therefore relates to pad weight under those specified testing periods, rather than to a direct count of leakage episodes or a reported measure of quality of life.

A relative percentage comparison can communicate change in relation to a participant’s baseline level, while the mean describes the average across the analyzed observations. The standard deviation, when reported, describes how spread out individual observations are around that mean. The registry lists the endpoint’s dispersion as standard deviation, but does not report the observed mean percentage change or the standard deviation. The specific analysis population and handling of repeated measurements are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a continuous primary outcome: mean percentage change in PWG. A continuous measure can take a range of values rather than representing a simple category such as event or no event. The mean summarizes the average measured value across observations included in the analysis. The standard deviation describes the spread of those values around the mean. Together, they can convey both the average result and how much observations differ, but neither is reported numerically for this endpoint in the registry record.

What does the baseline comparison represent?

Each participant’s baseline period supplies a reference measurement without the device. The endpoint description compares the average PWG during device use with the average PWG during baseline. This is a within-subject comparison: the reference comes from the same participant, rather than from a separate control group. Pairing measurements within a person can account for stable differences between people, but it does not remove changes over time or other influences that differ between baseline and device use. That is a general feature of before-and-after designs.

The registry describes a 3-day baseline pad period and pads worn for 8 hours a day. It then describes device use with pads for up to 8 hours. Although a percentage comparison is specified, the registry’s written formula is not accompanied by reported values from which the endpoint can be checked or interpreted. No numerical outcome or dispersion is reported, so the size of the mean change and its spread cannot be evaluated.

What does the mean tell a reader?

A mean is a measure of the center of a set of observations. It does not show the full distribution. Individual participants can have results that are close to or far from the mean, and a small number of observations can make the mean sensitive to unusual values. The standard deviation is one measure of variability, but it is not a confidence interval and does not directly state how precisely the population mean has been estimated.

A confidence interval, in general, gives a range of values compatible with the data and the method used to calculate it. Its width depends on the estimate’s uncertainty and the analysis assumptions. No confidence interval for the primary endpoint is reported in the registry record. Without an estimate and a measure of uncertainty, precision cannot be described. A p-value is also not reported for this endpoint, and the registry does not state an inferential analysis plan.

Why does the single-group design matter?

The comparison to baseline is not a randomized treatment-versus-control contrast. It can describe observed change between two measurement periods, but causal interpretation is more limited because the device is not compared with a concurrent control condition. For example, general changes in behavior or testing conditions could affect measurements across periods; the registry record does not say whether such changes occurred. This design feature should not be confused with a flaw in the arithmetic of the endpoint. It limits what the comparison can establish.

The intervention description also indicates that subjects used different SMDs and that not every subject used every type. The record does not state the order of use, the allocation of designs, or how results across designs were combined. If observations from multiple designs or periods were included, their dependence within a participant would matter to the analysis. In general, repeated observations from the same person are not independent in the same way as observations from different people. The registry does not report whether or how this dependence was handled.

What does over-dispersion mean in general?

Over-dispersion describes variability greater than a statistical model expects. It matters when a model assumes less variation than is present, because standard errors and uncertainty estimates may then be too small. This is a general concept rather than a finding about this study. The primary endpoint is continuous and the registry names standard deviation as its dispersion measure; it does not report an over-dispersion assessment or a model for the endpoint.

Planning calculations based on an observed effect can illustrate how a hypothetical two-arm study might be sized under stated assumptions. The registry’s planning description specifies a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of the observed effect. Such illustrations are not observed power, do not establish that the original study was adequately sized, and are not a substitute for reporting the outcome estimate and its uncertainty. The registry record does not report the study’s own sample-size justification.

For time-to-event outcomes, a general planning method may be based on event counts; this study’s listed primary outcome is continuous, not time-to-event. No time-to-event primary outcome is described in the registry record. More broadly, statistical methods should be interpreted in light of the outcome type, design, analysis population, and missing-data handling. The registry does not report enough analysis detail to determine these elements for the primary endpoint.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("SMD 12 2008", "SMD 12 2009", "SMD 9", "Cleared TIPI Device (G3)")
n   <- c(5, 6, 7, 7)
m   <- c(90.8, 98.5, 99.3, 89.3)
sp  <- c(16.9, 1.35, 0.61, 17.9)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  SMD 12 2008  5  90.800  16.900  69.816  111.784
CARM  SMD 12 2009  6  98.500  1.350  97.083  99.917
CARM  SMD 9  7  99.300  0.610  98.736  99.864
CARM  Cleared TIPI Device (G3)  7  89.300  17.900  72.745  105.855

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the mean percentage change in PWG. It does not report a multiplicity plan, a hierarchy of outcomes, or a procedure for adjusting for multiple comparisons. The intervention description includes different slightly modified designs, and not all subjects were to use all types, but the record does not describe how many design-specific comparisons were intended or how such results were to be interpreted. Any adjustment for multiple designs or analyses is not reported in the registry record.

The record lists no analysis records. It does not report the analysis population for the primary endpoint, the number of participants with evaluable endpoint measurements, or whether all enrolled subjects were included in the analysis. The recorded enrollment is 7, but enrollment alone does not establish how many participants contributed usable baseline and device-use measurements.

Missing-data handling is not reported in the registry record. There is no description of whether missing pad measurements occurred, how incomplete measurement periods were handled, or whether any values were imputed or excluded. The endpoint requires baseline and device-use measurements for a comparison, but the record does not state how a participant lacking either measurement would be treated. These omissions prevent assessment of whether the reported analysis, if conducted, could be affected by missingness.

The registry also does not report an interim-analysis plan, stopping rules, or a protocol for selecting among device designs. Their absence from the record should not be taken as proof that no such procedures existed; their status is simply not reported. With the analysis details unavailable, the reported endpoint definition should be read as a description of what was to be measured, not as a complete statistical analysis plan.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists one group, TIPI Vaginal Pessary, with 7 participants at risk for serious adverse events and 0 recorded as affected. For other adverse events, it lists 7 at risk and 4 affected. These counts should be read as descriptive registry figures for this group, not as estimates comparing the device with another treatment or with no device.

The record does not provide the specific adverse-event terms: the list of top serious terms is empty. It also does not describe the nature, severity, timing, duration, or outcome of the other adverse events. The figures alone cannot show whether the events were related to device use, whether more than one event occurred for an affected participant, or how events were collected and classified. Those details are not reported in the registry record.

A count of 0 serious adverse events in this group is not proof that serious events cannot occur. A small study and limited event information constrain what can be learned from a zero count. Likewise, the count for other adverse events is not a comparative risk estimate, because no concurrent control group is listed. These registry figures describe what was recorded; they do not establish a causal relationship or provide a complete safety profile.

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

The record establishes that a small, single-group study was conducted to evaluate TIPI vaginal pessary designs and that the primary endpoint was defined around change in pad weight gain from baseline. It gives a procedure for baseline pad measurement and describes device use for up to 8 hours. It also records enrollment and group-level adverse-event counts. These are useful details about the study’s structure and intended measurement.

The central result needed to judge the primary endpoint is not reported in the registry record. No mean percentage change in PWG, standard deviation, confidence interval, or p-value is reported. The direction and magnitude of the observed endpoint therefore cannot be stated, and its statistical precision cannot be judged. A study purpose or endpoint definition is not itself a finding.

Even if an observed baseline-to-device change were available, the single-group design would support a descriptive comparison rather than a randomized estimate against a concurrent control. A change from baseline could reflect the device, but it could also reflect other differences between measurement periods. The registry record does not report information that would separate those possibilities. The note that subjects used different designs, and not all used all types, also means that design-specific conclusions cannot be drawn without results and analysis details.

The safety counts should likewise be interpreted narrowly. The registry records 0 serious adverse events among 7 at risk and 4 affected under other adverse events among 7 at risk. The types and circumstances of those events are not reported. These counts do not establish comparative safety or explain whether events were related to device use.

In short, the record describes the study question and measurement framework, but not the primary outcome result. It cannot establish how much PWG changed, how consistently it changed, or how precisely any estimate was measured. Those limits concern the information available in the registry record; they are not a conclusion about what the study may have found outside that record.

14. Why This Trial Matters Statistically

This study is statistically useful as an example of how a device-performance question can be framed around a continuous, within-subject measurement. The baseline period gives a reference for each participant, and pad weight provides a recorded measure used to assess leakage under specified test conditions. The endpoint is a mean percentage change, so interpretation would require both an estimate of the average and information about its variability.

The design also illustrates why the comparison structure matters as much as the endpoint definition. A single-group baseline comparison and a randomized comparison against a concurrent control answer different questions. The former describes change relative to baseline among participants measured; it does not by itself isolate the contribution of the device from other changes over time. Readers should distinguish that descriptive question from a causal treatment comparison.

The small recorded enrollment of 7 makes clear why transparent reporting of participant flow, outcome values, and uncertainty is important. Enrollment does not reveal how many observations were available for analysis. Without a reported mean, standard deviation, or other uncertainty measure, readers cannot assess variability or precision. With multiple modified designs and incomplete exposure to some designs, design-specific reporting and a clear account of how observations were analyzed would also be important.

Finally, this record demonstrates the difference between a prespecified measurement description and a report of results. The primary endpoint and procedure are described, but the numerical result and analysis details are not reported in the registry record. The adverse-event counts are available but lack event descriptions and a comparator. Statistically, the most important lesson is to keep the design, measurement, analysis, and completeness of reporting distinct when deciding what evidence a registry entry can support.

15. 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 principal limitation of the available record is that it does not report the numerical result for the primary endpoint. The mean percentage change and its standard deviation are named as the outcome and dispersion measure, but neither value is given. There is therefore no basis in the registry record for evaluating the size, direction, variability, or precision of the primary result.

The study is recorded as single-group, with allocation listed as NA and masking as none. The described comparison is device use against baseline, not against a concurrent control arm. This limits causal interpretation of any change. The registry does not provide further details on how baseline and device-use measurements were paired or combined.

The recorded enrollment is 7, but the number analyzed for the primary outcome is not reported. The record does not say whether every subject completed the baseline period and device testing, how many observations were available for each design, or how missing measurements were handled. It also does not report the order of device use, the number of modified designs, or the analysis used to account for repeated measurements within subjects.

Only one outcome measure and no analysis records are listed. Statistical procedures, multiplicity handling, analysis populations, and interim analyses are not reported in the registry record. No sample-size justification is reported. The planning description refers to illustrations based on an observed effect, but it does not supply the numerical observed effect in the registry record; such illustrations would not replace an account of the study’s own design rationale or observed outcome.

Safety reporting is limited to group counts. Specific event terms, severity, timing, and attribution are not reported. The record also does not provide a comparison group for interpreting those counts. These limitations mean that the registry entry supports a description of the study framework and recorded counts, but not a detailed assessment of efficacy, precision, or comparative safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Preliminary Performance Study of the New TIPI Device in the Prevention of Stress Urinary Incontinence — NCT01770691.
• Registry record last updated 2015-01-16; status last verified 2015-01.
• Results first posted 2015-01-16.
• 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.

19. Record Summary

NCT01770691 is a completed, single-group device study sponsored by Assuta Hospital Systems. The record lists enrollment of 7, a study start of 2007-09, and primary completion of 2009-06. Its stated purpose was to evaluate performance of new TIPI designs for temporary management of stress urinary incontinence.

Subjects were to use different slightly modified TIPI vaginal pessary designs, although not all subjects would use all types. The primary endpoint was mean percentage change in pad weight gain, comparing average device-use measurements with a baseline period. The record describes a 3-day baseline pad period and device use for up to 8 hours.

The registry does not report the observed primary endpoint mean or standard deviation, analysis population, or statistical analysis details. It lists 0 serious adverse events among 7 at risk and 4 affected under other adverse events among 7 at risk, without event descriptions. The findings and their precision therefore cannot be assessed from the registry record.