Negative Pressure Wound Therapy-PICO: Cosmesis in Repeat C-Sections: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Negative Pressure Wound Therapy-PICO: Cosmesis in Repeat C-Sections (NCT05266053), a randomized na study. The primary outcome is Subjective Cosmetic Result.

2. Clinical Question

3. Trial Design

The registry describes a randomized, parallel-group trial of PICO 7 negative pressure wound therapy versus a standard wound dressing for women undergoing repeat cesarean sections. Participants were assigned to a treatment group or a control group. Masking was listed as none, so the registry does not describe the study as blinded. The phase is listed as not applicable. The study status is completed, with enrollment recorded as 24.

The study began on 2022-07-28, and primary completion was recorded as 2023-05-01. These dates describe the registry record and do not, by themselves, explain how recruitment or follow-up proceeded. The allocation ratio, sequence-generation procedure, concealment process, and site count are not reported in the registry record. The rationale for the enrollment target and any formal sample-size justification are also not reported in the registry record.

The intervention was the PICO 7 dressing, while the control group received a standard dressing described as gauze and bandage. The primary outcome was subjective cosmetic result at Week 6. Although the overall enrollment is recorded as 24, the primary outcome summaries are based only on participants evaluated at Week 6: 8 in the Treatment Group and 4 in the Control Group. The registry does not report why those endpoint counts differ from overall enrollment or whether any participants lacked an assessment for particular reasons.

The registry lists procedure time, pain scores at 48 hours and 72 hours, pain scores at 4 weeks and 6 weeks, and incision-healing complications up to 42 days postoperatively as secondary outcomes. Results for those outcomes are not reported in the registry record in the registry record for this analysis. The randomized design is relevant to the intended comparison, but the small endpoint groups and the limited posted outcome information constrain what can be concluded from the reported summaries.

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: There are no pre-assignment factors that impact participant enrollment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The only subjects analyzed were those that were evaluated in week 6

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 Subjective Cosmetic Result, measured over Week 6.

The primary endpoint is the subjective cosmetic result at Week 6, measured with the Patient and Observer Scar Assessment Scale (POSAS). Participants answered questions about vascularity, pigmentation, thickness, relief, pliability, and surface area. Each response uses a scale from 1 to 10, where 1 represents the least severe appearance and 10 the most severe. The six responses are summed, giving totals from 6, described as the best outcome, through 60, described as the worst outcome.

This kind of patient-reported scar assessment is used to capture aspects of appearance that a participant can judge directly. It translates several subjective features into a common score, making it possible to describe the distribution of scores between randomized groups. A lower total indicates a less severe assessed appearance according to the scale definition. The posted endpoint is summarized by the median and full range rather than by a mean and standard deviation.

The record says the full range reflects the actual collected data from participants, and that only subjects evaluated in Week 6 were analyzed for this endpoint. This matters when interpreting the summaries: they characterize the Week 6 assessments available for analysis, not necessarily every enrolled participant. The registry does not report additional details about questionnaire administration, assessor procedures, or how missing questionnaire items were handled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is reported as a median with a full range. The median is the middle of an ordered set of observations and is useful when the goal is to describe a typical score without relying on the arithmetic mean. The full range reports the lowest and highest observed values. It communicates the span of recorded scores, but it does not show how many observations lie near either end or whether most observations cluster around the median. In this trial, the listed summaries are 13.0 with a range of 10.0 to 16.5 for the Treatment Group and 26.5 with a range of 16.0 to 36.5 for the Control Group.

The choice to report a median is consistent with describing a bounded questionnaire total using a robust center. As a general statistical point, medians can be less affected by extreme observations than means. A range is also easy to interpret, but it is sensitive to the most extreme observed scores and becomes less informative about the distribution when the group is small. Neither a median nor a range supplies a measure of uncertainty for a between-group comparison. The registry record does not report a confidence interval or a statistical test for the primary comparison.

Random assignment is intended, in general, to create groups that are comparable on average with respect to both measured and unmeasured characteristics. In a small trial, however, chance differences between groups can remain, and the actual balance cannot be evaluated from the primary summaries alone. The registry records randomized allocation and a parallel model, but does not report the allocation procedure, concealment details, or baseline characteristics in the registry record for this analysis. Those details are not reported in the registry record.

A confidence interval is a statistical tool for expressing the uncertainty around an estimate. In a comparative trial, it can show which values for the underlying group contrast remain compatible with the observed data under the specified method. It is not reported for this endpoint. A p-value, if reported, would address compatibility of the data with a specified null model; it would not measure the size or clinical importance of a difference. No p-value or other inferential result for the primary comparison is reported in the registry record. Thus, readers should not infer statistical significance from the visual or numerical separation of the group medians.

For outcomes that are counts or rates, the choice of statistical model depends on how the outcome is distributed and on the design. As a general explanation, over-dispersion occurs when observed variability exceeds what a model assumes; ignoring it can make uncertainty appear too small. That issue cannot be assessed for this POSAS result from the posted summaries, and the record does not state that an over-dispersion model was used. The endpoint is a scale score summarized with medians and ranges, not a count outcome in the registry record.

The registry also includes a sample-size planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The illustration considers detecting a stated fraction of the observed effect. Such calculations are planning scenarios, not observed power and not evidence that the completed trial had a particular probability of detecting an effect. The registry record does not report the trial's own design assumptions or sample-size justification. No planning values need to be interpreted as trial outcomes.

The entry records zero posted analyses. The available primary outcome information is descriptive, and no sponsor analysis is reported in the registry record for this endpoint. There is no discrepancy between a sponsor analysis and a recalculated result indicated in the registry record. A recalculation from summary statistics would not replace a prespecified, properly conducted analysis, particularly where participant-level data and analysis details are unavailable. The record does not report an analysis model, adjustment strategy, handling of ties, or an estimand for the primary comparison.

General guidance for reading these results is to distinguish the observed summaries from uncertainty estimates and from causal conclusions. The randomized design frames the intended comparison, but the Week 6 counts are limited and the registry reports no inferential comparison. The full ranges describe observed extremes only. The medians describe the central score in each evaluated group, and the POSAS scoring direction gives those medians a descriptive interpretation. None of these alone answers how precise or reproducible a between-group difference may be.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists six secondary outcomes: procedure time, pain scores at 48 hours and 72 hours, pain scores at 4 weeks and 6 weeks, and incision-healing complications up to 42 days postoperatively. Alongside the primary cosmetic endpoint, these outcomes create several opportunities for comparisons. As a general statistical principle, examining multiple outcomes can increase the chance of a seemingly notable finding arising by chance if each is tested separately. Methods for controlling or interpreting multiplicity depend on the analysis plan and the inferential goals.

The registry record does not report a multiplicity adjustment, a hierarchy for testing outcomes, or a plan for interpreting the collection of endpoints. Results for the listed secondary outcomes are not reported in the registry record in the registry record for this analysis. Therefore, no claim about those outcomes or about the overall pattern of results can be made from the primary endpoint summaries alone.

For the primary endpoint, the registry specifies that only subjects evaluated in Week 6 were analyzed. The reported counts are 8 in the Treatment Group and 4 in the Control Group. The total enrollment is recorded as 24, but the record does not explain the difference between enrollment and the endpoint analysis counts. Reasons for missing Week 6 assessments, the amount and pattern of missing data, and any imputation or sensitivity analysis are not reported in the registry record.

The registry also does not state whether the primary analysis followed intention-to-treat principles, a per-protocol definition, or another analysis population. Without those details, it is not possible to determine how participants were handled after randomization if they did not complete an assessment or deviated from assigned treatment. These gaps limit assessment of potential bias from missing outcomes and of the extent to which the analyzed groups preserve the randomized comparison.

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.

The adverse-event figures report zero serious adverse events in the Treatment Group and zero in the Control Group. The record also reports zero other adverse events and zero deaths in each group. For each group, the listed number at risk is 12 for serious events and 12 for other events. These are the posted registry figures; they should not be interpreted as proof that no events could occur or that the groups have identical safety profiles.

Event counts describe what was recorded during the study, while the number at risk indicates the group count associated with that reporting. A zero count means no event of that category was reported in the listed group; it does not measure the rate of an event beyond the period and population captured by the registry entry. The record does not give further details about event definitions, surveillance procedures, severity grading for non-serious events, or the duration of safety follow-up beyond the listed information.

With no reported events in either group, these figures do not support a comparative estimate of relative risk or a precise estimate of the underlying event frequency. Rare events can remain uncertain when observed counts are zero, especially when the number at risk is limited. The registry lists no serious-event terms. Safety interpretation should remain confined to the recorded counts, not extended to unreported outcomes or longer-term risks.

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

The result establishes a descriptive fact about the Week 6 assessments recorded in the registry: the median POSAS score was 13.0 in the Treatment Group and 26.5 in the Control Group. Because lower scores indicate less severe appearance on the defined scale, the treatment-group median is lower in these observed data. The posted ranges are 10.0 to 16.5 and 16.0 to 36.5, respectively. These values characterize the participants evaluated at Week 6, not necessarily all those enrolled.

The result does not establish the size or precision of a population-level difference. The registry record does not report a confidence interval, a p-value, or another inferential analysis for the primary comparison. A difference between observed group summaries can reflect a true effect, chance variation, differences among the assessed participants, or other sources of bias. Without further analysis and information about missing data and outcome assessment, those possibilities cannot be separated.

It also does not establish that the dressing caused the observed pattern, even though the study used randomized allocation. Randomization is a design strength, but interpretation still depends on appropriate conduct, adequate follow-up, outcome measurement, and analysis. Masking was listed as none, and the registry does not report further procedures for limiting assessment bias. The endpoint counts are limited, and the analysis population was restricted to subjects evaluated at Week 6.

The primary endpoint is one aspect of the study question: subjective cosmetic appearance. The registry lists pain, procedure time, and wound-healing complications as secondary outcomes, but their results are not reported in the registry record. Therefore, the cosmetic summaries do not give a complete account of recovery, safety, or the balance of outcomes. They also do not establish how participants would value the observed scores or whether any difference would be meaningful to patients; that information is not reported in the registry record.

The most defensible reading is narrow and descriptive. The observed Week 6 median was lower in the PICO group on a scale where lower totals represent less severe appearance. The extent of uncertainty and the broader clinical meaning of that pattern remain unresolved by the posted registry results.

13. Why This Trial Matters Statistically

This trial is statistically useful as an example of why a reported group summary must be read alongside the analyzed population and the uncertainty available. The registry records overall enrollment as 24, but the primary endpoint counts are 8 and 4 for participants evaluated at Week 6. The difference between enrollment and those endpoint counts is important context, while the reasons for it are not reported in the registry record.

The endpoint uses a defined patient-reported scale with a clear direction: lower totals represent less severe appearance. That makes the medians straightforward to describe, but the absence of inferential results limits how far the comparison can be taken. A descriptive contrast is not the same as an estimate whose precision has been quantified, and it is not equivalent to a causal conclusion. This distinction is central to statistical interpretation in small clinical studies.

The randomized, parallel-group design provides a framework for comparing the two dressing approaches. At the same time, no masking was reported, the endpoint is subjective, and the record does not describe the assessment process in detail. These features make transparent reporting of outcome collection and analysis especially useful. The registry does not report a primary comparison test, confidence interval, missing-data method, or multiplicity approach.

The entry also lists several secondary outcomes, but their results are not reported in the registry record. This highlights a broader reporting issue: a primary result alone cannot answer every question posed by a study, particularly when the outcomes include pain, procedure time, and healing complications. Readers need outcome-specific results and analysis context to judge the full evidence. The trial matters statistically because it shows both the value of a defined endpoint and the limits of interpreting a small, incompletely characterized set of outcome summaries.

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 endpoint analysis includes only participants evaluated at Week 6. The reported counts are 8 in the Treatment Group and 4 in the Control Group, while enrollment is recorded as 24. The registry does not explain the reasons for the difference, describe missing assessments, or report whether any method was used to address missing data. This prevents assessment of whether the observed endpoint groups represent the randomized groups adequately.

The record gives medians and full ranges but no confidence interval, p-value, or other inferential comparison. The precision and statistical uncertainty of the group contrast therefore cannot be evaluated from the posted primary summaries. The record also does not report participant-level scores, an adjusted analysis, or a prespecified analysis model. No baseline characteristics are included in the registry record for this analysis, so group comparability after randomization cannot be assessed from those details.

The primary measure is subjective, and masking is listed as none. The registry does not describe who administered or scored the POSAS assessment, whether assessors were independent, or whether the same procedures were used across groups. Those details matter for understanding the possibility of measurement bias. The record does not report the clinical importance threshold for a score difference, so the practical meaning of the observed medians cannot be determined.

Secondary outcomes are listed, but their results are not reported in the registry record. The record also does not describe how multiple outcomes were handled statistically or provide additional safety-event definitions and follow-up detail. Finally, the enrollment target rationale and the trial's own sample-size justification are not reported in the registry record. Together, these limitations mean that the available information supports a cautious descriptive reading rather than a definitive comparative conclusion.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Negative Pressure Wound Therapy-PICO: Cosmesis in Repeat C-Sections — NCT05266053.
• Registry record last updated 2024-09-03; status last verified 2024-08.
• Results first posted 2024-09-03.
• 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

NCT05266053 is a completed randomized, parallel-group trial comparing PICO 7 negative pressure wound therapy with a standard wound dressing after repeat cesarean sections. Masking was listed as none. Enrollment was recorded as 24. The study began on 2022-07-28, and primary completion was recorded as 2023-05-01.

The primary outcome was subjective cosmetic result at Week 6, measured with the POSAS scale. Among participants evaluated at that time, the Treatment Group median was 13.0, with a full range of 10.0 to 16.5; the Control Group median was 26.5, with a full range of 16.0 to 36.5. Lower scores indicate less severe appearance. The registry does not report an inferential comparison for this endpoint.

Listed secondary outcomes include procedure time, pain at multiple time points, and incision-healing complications. Their results are not reported in the registry record in the registry record for this analysis. The registry reports zero serious adverse events, zero other adverse events, and zero deaths in each group.