Study on Adhesion Properties of Three Different Adhesives: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study on Adhesion Properties of Three Different Adhesives (NCT04125797), a na na study. The primary outcome is Number of Participants Who Achieved Adhesion Success After 72 Hours.

2. Clinical Question

The study asks whether each of three experimental skin adhesives remains attached to skin after a minimum of 72 hours when worn by healthy adult female volunteers. The primary endpoint is the number of participants meeting the registry’s definition of adhesion success. Success is defined as more than 75% adherence, assessed when the adhesives are removed. The assessment uses a five-point scale, and the least favourable score from the two patches of each adhesive type is used for that participant and adhesive.

This is a product-performance question under the stated wearing and assessment conditions. It is not a question about clinical outcomes or comparisons with usual care. Because the same participant tested all three adhesives, the observations have a within-participant structure: each person contributes information on each adhesive type. A comparison should therefore account for the fact that measurements from the same person may be related. The statistical method used for any such comparison is not reported in the registry record.

3. Trial Design

The registry identifies this as a completed, single-centre study with a single-group model. The listed enrollment is 39, and the study dates are 2019-10-07 to 2019-10-31 for the start and primary completion. The population is described as healthy adult females. The study summary says the centre would enroll 39 subjects, including a 20% dropout allowance, within a four months period. The actual number enrolled, the number completing the wearing period, and the number included in the primary endpoint analysis are not reported in the registry record.

Each participant was to attend two sessions. At the first session, six adhesive patches were applied below the participant’s bra: two patches of each of three adhesive types. The arm description says one set of each adhesive was placed on the right side of the trunk and another set on the left. The adhesives were removed at the second visit after a minimum of 72 hours. The more detailed placement procedure is incomplete in the registry record, so further allocation of adhesive positions cannot be described.

There is an internal difference in how the study is characterized. The brief summary calls it a double-blinded, case control study, while the registry design fields identify a single-group model, allocation as NA, and masking as none. The record does not explain this difference. It also does not describe randomized assignment of adhesive positions or a separate control group. The study should therefore not be read as a randomized, parallel-group comparison.

The listed intervention is application of adhesive, with the three adhesives tested within each participant. The record names Ambu A/S as sponsor. It gives no statistical analysis plan, no detailed account of the analysis population, and no results for the primary endpoint. Those details 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.

Before assignment: This clinical investigation was a single centre, double blinded, case control study in healthy adult females. The investigation centre enrolled 39 subjects within one month. The three (3) types adhesive were randomly placed on subject's trunk. Each study participant will test two patches of each of three different experimental adhesives. Six patches in total. One set of each adhesive will be placed on the right side of the trunk while another set will be placed on the left side of the trunk.

Overall Study

Reasons for not completing this period:

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: All the subjects met the inclusion/exclusion criteria.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Who Achieved Adhesion Success After 72 Hours, measured over After a minimum of 72 hours (no more than 3 days) after application the adhesives will be removed and assessed by a medical doctor.

The primary endpoint is the number of participants who achieved adhesion success after a minimum of 72 hours. Adhesion is evaluated when the patches are removed by a medical doctor. The registry defines success as more than 75% adherence. It also describes a five-point rating: 0 means at least 90% adhered, 1 means at least 75% to less than 90% adhered, 2 means at least 50% to less than 75% adhered, 3 means greater than 0% to less than 50% adhered, and 4 means 0% adhered. The least favourable of the two patch scores for each adhesive type is used.

This endpoint turns an assessment of how much of a patch remains attached into a participant-level count. Such a count can be easy to interpret as a number of people meeting a defined criterion, but it also discards detail in the underlying scale. Two participants with different degrees of adherence can both be classified as successful if they meet the success threshold. Conversely, the use of the least favourable patch score means that one poorly adhering patch determines the participant’s score for that adhesive type.

The description has a boundary distinction worth noting: the binary definition says more than 75% adherence, whereas the five-point scale places at least 75% through less than 90% in score 1. How a score of exactly 75% is classified for the binary endpoint is not clarified in the registry record. The primary endpoint result and any uncertainty estimate are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a binary participant-level classification for each adhesive type: success or not success. In general, a binary outcome records whether a defined event occurred rather than the amount or severity of a continuous measurement. Here the underlying observation is a five-point adhesion rating, but the primary question reduces that rating to whether the patch meets the stated adherence threshold. A count of successes can be informative, but interpretation requires knowing the denominator as well as the number meeting the criterion. Neither the primary success counts nor their denominators are reported in the registry record.

What the five-point rating contributes

The rating distinguishes degrees of lift-off, from essentially no lift to a patch that is detached. In general, retaining an ordered scale can preserve more information than collapsing it into a binary outcome. The registry’s primary endpoint instead uses a success threshold and the worst of two patch scores of each type. This approach emphasizes whether a participant’s less favourable patch met the criterion, rather than averaging the two patches or using the better-performing patch. The record does not provide the score distributions or explain why this summary rule was selected.

The definition also describes a boundary that needs operational clarity. The binary rule uses more than 75% adherence, while the scale assigns score 1 to at least 75% and less than 90%. These wordings differ at exactly 75%. The registry record does not explain how that boundary was handled when deriving the binary endpoint.

Why the participant structure matters

Each participant tests all three adhesive types, with two patches per type. In general, measurements from the same person are often more alike than measurements from different people because they share participant characteristics and study conditions. A method that treats every adhesive observation as independent may therefore misrepresent uncertainty. A within-participant comparison can use the fact that each person contributes observations for all adhesive types, but the appropriate method depends on the endpoint and the analysis objective. The statistical method actually used is not reported in the registry record.

The study is described in the design fields as single group, with allocation NA and masking none. The brief summary uses the terms double blinded and case control. The registry does not reconcile these descriptions. It does not report randomized assignment of patch locations or a separate control group. Thus, the study structure should not be mistaken for a conventional randomized comparison between independently assigned groups.

Uncertainty and testing

In general, a confidence interval gives a range of values compatible with the observed data under a specified statistical model. Its width reflects precision: a wider interval indicates greater uncertainty about the value being estimated. A p-value, when used, measures how unusual the data would be under a specified null model; it is not a measure of the size or clinical importance of an effect. The registry record reports no confidence intervals, p-values, or primary endpoint estimates, so these interpretations cannot be applied to a reported adhesion result.

Multiplicity arises when several outcomes, comparisons, time points, or analyses are considered. Repeated testing can increase the chance that at least one result appears notable by chance. The record lists six outcome measures and identifies secondary outcomes involving itchiness at 24, 48 and 72 hours, ease and pain of removal after 72 hours, skin reaction after wearing the adhesive for 72 hours, and residue after removal. It does not report a multiplicity strategy or a complete analysis plan. The presence of several outcomes does not by itself establish that any particular adjustment was required or used.

Planning illustrations and analysis reporting

The sample-size assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They specify that the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not observed trial findings or observed power. In general, power is a design-stage probability under assumed conditions; it cannot be inferred as a measure of what the completed trial demonstrated. The illustration’s two-arm equal-allocation framework does not match the registry’s single-group description in which each participant tests all three adhesives. The record does not report the illustration’s numerical outputs or the observed effect used for it.

The registry lists zero analyses. This means that analysis details are absent from the posted record; it does not establish that no analysis was conducted. The sponsor’s analysis, any adjusted or unadjusted estimates, the model specification, the handling of repeated observations, and the uncertainty calculations are not reported in the registry record. Without those details and the outcome counts, statistical conclusions about relative adhesion performance cannot be drawn from this record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures. Alongside the primary adhesion-success endpoint, the secondary outcomes include itchiness at 24, 48 and 72 hours; ease of removal after 72 hours; pain during removal after 72 hours; skin reaction after wearing the adhesive for 72 hours; and adhesive residue after removal. Considering several outcomes can be useful when describing different aspects of wear and removal, but it also raises questions about which outcomes were considered primary for inference and whether any adjustment for multiple testing was planned. A multiplicity strategy is not reported in the registry record.

The record does not give a statistical analysis plan, analysis populations, or methods for comparing the three adhesive types. It does not report whether analyses were intended to use all randomized or enrolled participants, only participants who completed the wearing period, or another defined group. Randomization is not described in the design fields. The handling of repeated measurements within participants, missing outcome data, and participants who withdrew is not reported in the registry record.

The summary states that withdrawals would not be replaced because dropout was included in the planned sample size, and it describes a 20% dropout allowance. It does not report how many participants withdrew or whether any observations were missing. The registry enrollment is 39, but the primary endpoint denominator is not reported. As a result, the extent to which missingness could affect the reported endpoint cannot be assessed from this record. No analysis results or analysis entries are reported in the registry record.

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 non-serious adverse event terms

The adverse-event summary lists 38 participants at risk for serious adverse events, with 0 serious adverse events reported, and 38 at risk for other adverse events, with 1 other adverse event reported. It also lists 0 deaths. These are counts in the registry record, not estimates of comparative risk between adhesive types.

The record does not identify the other adverse event, describe its severity or timing, or state whether it was considered related to an adhesive. No serious adverse-event terms are listed. The definitions and collection procedures used for these categories are not reported in the registry record. The listed group is All Study Participants; separate safety results for each adhesive type are not reported.

The 38 participants at risk in the safety summary should not be assumed to be the denominator for the primary adhesion endpoint. The registry lists enrollment of 39, but it does not report the number with evaluable adhesion assessments. Safety counts describe what was recorded under the posted categories; they do not establish that no other events occurred outside those categories or that the adhesives are safe in other populations or settings.

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

The registry describes a study designed to assess whether three experimental skin adhesives remained attached over a minimum of 72 hours in healthy adult female volunteers. Each participant was to test two patches of each adhesive, with the least favourable patch score used for the adhesive-specific assessment. This repeated, within-participant arrangement means that comparisons among adhesives would need to be interpreted with the participant-level pairing in mind.

The posted record does not include the primary adhesion-success counts, the number assessed for that outcome, comparative estimates, or uncertainty measures. It therefore does not show how many participants met the success criterion for any adhesive or whether the adhesive types differed. The record also does not give the statistical methods used for primary or secondary outcomes. The completed status alone does not supply those missing results.

The safety summary reports 0 serious adverse events among 38 participants at risk, 1 other adverse event among 38 at risk, and 0 deaths. Further information about the other event and its relationship to the adhesives is not reported. Those figures describe the posted safety categories and should not be interpreted as a complete characterization of safety beyond the study population and record.

The study is limited to healthy adult female volunteers at a single centre and to the stated wear and assessment conditions. It does not, from the registry information, establish how adhesives perform in other populations, clinical settings, or use conditions. Nor does it provide evidence about broader clinical outcomes. The record supports describing the study question and design, but the absent primary results and analysis details prevent a conclusion about comparative adhesion performance.

13. Why This Trial Matters Statistically

Statistically, this study is notable for its within-participant design: every participant tests each of three adhesives, rather than being assigned to one adhesive group. That structure can make direct comparisons efficient because each participant serves as a reference for their own observations. It also requires methods that recognize the relationship among results from the same person. Treating all observations as independent could give an inaccurate account of uncertainty.

The endpoint illustrates how a continuous or graded physical observation can be converted into a binary outcome. A binary success count is straightforward to communicate, but it depends on the threshold chosen and can conceal differences among participants who fall on the same side of that threshold. The use of the less favourable of two patch scores adds a conservative participant-level summary, while making the result sensitive to the poorer-performing patch. The record’s wording differs at exactly 75% adherence between the binary definition and the five-point scale, and does not clarify how that boundary is handled.

The study description also shows why design fields and narrative summaries should be read together. The registry design fields say single group, allocation NA, and masking none, while the brief summary calls the study double blinded and case control. The discrepancy is not resolved in the record. In addition, the sample-size assumptions describe equal allocation between two arms, which does not correspond directly to the recorded within-participant design. Such differences matter when assessing whether a planning framework matches the actual design.

Finally, a completed record without primary endpoint estimates or analysis details cannot answer the statistical question posed by the study. Clear reporting of denominators, outcome counts, paired comparisons, uncertainty, and missing data would be needed to interpret the adhesion findings.

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 registry record has important reporting limitations for interpreting this study. It does not report primary endpoint results, the number of participants assessed for adhesion, or estimates comparing the three adhesives. It also gives no confidence intervals, p-values, or statistical analysis methods. Although the record marks the study completed, completion status does not resolve the absence of outcome data.

The design descriptions do not fully align. The structured fields identify a single-group study with allocation NA and masking none, while the brief summary describes a double-blinded, case control study. The registry does not explain how those descriptions relate to the procedure. The arm description is also incomplete at its end, so the full method for positioning adhesive types cannot be recovered from the record.

The endpoint definition has a threshold ambiguity: the binary success rule requires more than 75% adherence, while the scale category for score 1 begins at 75%. The record does not say how a result at exactly 75% is classified for the primary endpoint. It also does not report whether the five-point ratings were assessed consistently across participants or whether assessors were blinded in practice.

The record lists enrollment of 39, but does not give actual completion, primary endpoint denominators, withdrawals, or missing-data handling. Safety information is reported for 38 participants at risk, with no further detail about the single other adverse event. The population is limited to healthy adult female volunteers at one centre, and the registry does not report results that would support generalization beyond those study conditions. Multiplicity handling, analysis populations, and the rationale for the sample-size assumptions are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study on Adhesion Properties of Three Different Adhesives — NCT04125797.
• Registry record last updated 2026-07-22; status last verified 2026-05.
• Results first posted 2026-07-22.
• 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

The registry record describes a completed, single-centre study of three experimental skin adhesives in healthy adult female volunteers. Each participant was to wear two patches of each adhesive and have them removed after a minimum of 72 hours. The primary endpoint is the number of participants achieving adhesion success, based on the least favourable of two patch scores for each adhesive type. Enrollment is listed as 39.

The primary endpoint counts, comparative results, statistical analyses, and analysis populations are not reported in the registry record. Safety information lists 0 serious adverse events among 38 participants at risk, 1 other adverse event among 38 at risk, and 0 deaths. The record contains differing descriptions of blinding and study design, and does not resolve them. It also does not report missing-data handling or a multiplicity strategy.