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 Compare Effect of Surgical Antiseptic Preparations on Incise Drape Adhesion to Skin (NCT01290978), a randomized phase 4 study. The primary outcome is Drape Adhesion.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01290978 |
| Phase | Phase 4 |
| Condition | Healthy |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 22 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Solventum US LLC |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes the condition as Healthy. The primary outcome population is identified as participants included in the per-protocol data analysis. Enrollment is reported as 22, while the arm-level outcome summaries each report n 22.0; the registry does not explain the relationship between those counts.
Intervention
One preparation was ChloraPrep, applied to the application site according to the manufacturer's instruction. The registry classifies it as a drug and reports its mean drape-removal force at 30 minutes.
Comparator
The other preparation was DuraPrep, also applied to the application site according to the manufacturer's instruction. It is the active comparator, rather than a no-preparation or placebo group, and its outcome is reported using the same measure and timeframe.
Primary question
The clinical question is whether the measured force needed to peel a surgical incise drape from the skin differs after preparation with ChloraPrep compared with DuraPrep. The primary outcome is described as the peel force to remove the sample, in grams-force, measured at 30 minutes. The registry reports a mean and 95% confidence interval for each preparation. It does not post an analysis of the between-preparation contrast, so the arm summaries alone do not establish the size or statistical uncertainty of that contrast.
3. Trial Design
The registry describes a prospective, randomized comparison of two presurgical skin antiseptic preparations and resulting surgical incise drape adhesion to skin. Allocation was randomized, the design model was parallel, and masking was listed as none. The study is classified as Phase 4 and its status is completed. The sponsor is Solventum US LLC. The recorded study start is 2010-02 and primary completion is 2010-03.
The two interventions were ChloraPrep and DuraPrep. Each was applied to the application site according to the manufacturer's instruction. No further details of the randomization procedure, assignment concealment, sequence generation, or conduct of the application are reported in the registry record. The registry does not describe whether participants, personnel, or outcome assessors knew treatment assignment beyond listing masking as none.
Enrollment is recorded as 22. The primary outcome summaries list n 22.0 for ChloraPrep and n 22.0 for DuraPrep. The registry does not explain how those arm-level counts relate to the enrollment figure. The primary outcome population is described as data analysis per protocol, but the criteria used to define that population and the number excluded from it are not reported in the registry record.
The primary outcome is drape adhesion, defined as the peel force to remove the sample, assessed at 30 minutes and expressed in grams-force. The registry reports a mean and 95% confidence interval for each arm. A secondary outcome is listed as skin assessment on Ioban, ActiGard, and Steri-Drape 2 application sites, but further results or analysis details are not reported in the registry record. The record lists two outcome measures and zero analyses.
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: Volunteers who met the exclusion/inclusion criteria were required to undergo a 1-day washout period where they were not allowed to use any moisturizing products or other skin contact materials on their backs. Two subjects were screen failures.
Overall Study
| Stage | ChloraPrep, DuraPrep |
|---|---|
| STARTED | 22 |
| COMPLETED | 22 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Data analysis per protocol
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: A sample size of 18 subjects and 18 drape samples per subject was determined to provide 80% power to detect a difference of 20% for the drape by prep comparison. A minimum of 20 subjects was used to account for the uncertainty in variability.
| Characteristic | Unit | ChloraPrep , DuraPrep |
|---|---|---|
| Participants analysed | 22 | |
| Age, Continuous | participants | 40.4 (SD 13) |
| Sex: Female, Male: Female | Participants | 11 |
| Sex: Female, Male: Male | Participants | 11 |
6. Primary Endpoint
The registry lists the primary outcome as Drape Adhesion, measured over 30 minutes.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | grams-force |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the force required to peel a sample of surgical incise drape from the skin. It is recorded in grams-force at 30 minutes, and the registry defines the outcome as the peel force to remove the sample. The reported measure is a mean, with a 95% confidence interval, for each preparation. The analysis population is described as per protocol.
This endpoint translates the idea of drape adhesion into a measured force. The measurement is relevant to the stated study purpose because the trial asks whether presurgical antiseptic preparations affect how well surgical drapes adhere to skin. A force measure allows the result to be expressed on a continuous scale, rather than simply recording whether adhesion was present or absent. In general, a continuous outcome can preserve information about variation across measurements, although the registry does not provide individual observations or a distribution plot for this trial.
The endpoint should be interpreted narrowly: it is a peel-force measurement at a specified time, not a direct measure of every aspect of drape performance or of a clinical outcome. The record does not report additional measurement details such as the equipment, precise testing procedure, assessor training, or repeatability. It also does not provide results for the listed skin assessment outcome. Those omissions limit what can be inferred about the broader performance of the drapes or the preparations.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports a mean peel force of 78.6 grams-force for ChloraPrep, with a 95% confidence interval from 68.0 to 89.2. For DuraPrep, it reports a mean of 181.3 grams-force, with a 95% confidence interval from 165.8 to 196.8. Both summaries refer to the primary outcome at 30 minutes and are presented for the per-protocol population. The reported intervals describe uncertainty around the arm-specific means, not directly around the difference between the two preparations.
The posted summaries place the DuraPrep mean above the ChloraPrep mean. That descriptive ordering is not itself a test of the contrast. The registry record does not report an estimated between-arm difference, its confidence interval, or a statistical test for the primary endpoint. It also lists zero analyses. As a result, the posted information does not establish the precision of the contrast or whether a prespecified statistical criterion was met. No p-value or adjusted analysis is reported in the registry record.
General statistical interpretation: a confidence interval gives a range of values compatible with the data and the method used to calculate the interval, under that method's assumptions. A 95% confidence interval is not a guarantee that the true mean lies in the particular interval, nor is it a direct statement about the probability that one preparation is superior. Here, the registry gives intervals for each arm separately. It would be incorrect to treat their endpoints as if they were the confidence interval for a comparison. Comparing arm-specific intervals by eye is not a substitute for a model or test of the treatment contrast.
The outcome summaries are means, so they convey the average measured force in each reported arm. The registry does not provide a standard deviation, standard error, individual-level data, or other distributional description. It is therefore not possible to assess from the record whether the measurements were symmetric, contained outliers, or varied substantially within an arm. The confidence intervals provide some information about precision of the means, but not the full pattern of individual measurements.
The enrollment and arm-level sample counts are not reconciled in the registry record. Because the analysis population is per protocol, it also matters that the record does not state the eligibility rules for that analysis or how participants with incomplete measurements were handled. The available result should therefore be understood as a posted arm-level summary, rather than a complete account of participant flow or an analysis of all randomized participants.
The randomized design provides a framework for comparing the assigned preparations, but the record does not report enough detail to evaluate the implementation of randomization or the statistical analysis. Masking is listed as none, which is relevant context for interpreting a measured outcome; additional information about who performed or assessed the peel-force measurement is not reported. The result is limited to the reported endpoint, timeframe, and analysis population. It does not on its own answer questions about other drape products, settings, outcomes, or clinical consequences.
9. Statistical Methods Explained
General explanation: the primary outcome is continuous because it is measured as force on a numerical scale. The registry reports the mean, which represents the arithmetic average of the recorded measurements within each arm. A mean is a useful summary of central tendency, but it can be influenced by unusually high or low observations. Without the individual observations or a measure of spread such as a standard deviation, the shape and variability of the outcome cannot be assessed from the registry record.
What do the confidence intervals describe?
The registry gives a 95% confidence interval for each arm mean. In general, a confidence interval reflects both the data and the assumptions of the method used to construct it. Repeated use of a valid method under its assumptions would produce intervals that contain the underlying quantity at the stated rate. For a particular study, the interval is not a probability statement about where the fixed population mean lies. It is also not an interval for the difference between arms unless the difference itself was calculated and its uncertainty estimated.
The record does not identify the confidence-interval calculation method. It does not say whether the method relied on a normal approximation, a t distribution, or another procedure, nor does it describe any handling of skewness or unusual observations. Therefore, an independent reader cannot reproduce or evaluate the interval calculation from the posted summary alone. The displayed means and intervals should be treated as the registry's reported summaries.
Why is a direct contrast important?
General explanation: a randomized parallel comparison is typically interpreted through a contrast between assigned groups. For a continuous outcome, that contrast may be expressed as a difference in means, with a confidence interval and, where appropriate, a test statistic or p-value. A direct contrast quantifies the estimated separation between groups and its precision. Separate arm means and separate arm confidence intervals are not a substitute because the uncertainty in a contrast depends on the variability and sample information in both arms and on the analysis used.
The registry record gives the arm means and confidence intervals but does not report a direct contrast or a primary-outcome test. It lists zero analyses. No standard error, p-value, model, or adjustment is posted for the comparison. Consequently, no inferential result for the contrast should be attributed to the registry. The arm values support a descriptive reading of the posted means, but not a claim about a formal statistical conclusion.
What does the randomized design contribute?
General explanation: random allocation is intended to create groups whose baseline characteristics are not systematically determined by treatment assignment. It supports causal interpretation when assignment is implemented as intended and the analysis respects the design, but randomization does not ensure that groups are identical in a particular small trial. The registry identifies the allocation as randomized and the model as parallel. It does not describe the sequence-generation method, concealment, stratification, or other implementation details, so these cannot be evaluated from the record.
Masking is listed as none. In general, lack of masking can matter when an outcome involves measurement or judgment, because knowledge of assignment may affect procedures or assessment. The endpoint is described as peel force, but the record does not say who performed the measurement, whether the procedure was automated, or whether assessors had access to assignment. Those details should not be inferred from the masking field.
What is the role of the per-protocol population?
The primary analysis population is described as data analysis per protocol. In general, a per-protocol analysis includes participants meeting protocol-defined requirements, but the specific rules vary by study. The registry does not state the definition used, how many participants qualified, whether participants were excluded after randomization, or how deviations were handled. It also does not report an intention-to-treat analysis. The arm-level n values therefore cannot be used to reconstruct participant flow or determine whether all randomized participants contributed outcome data.
How should planning illustrations be understood?
General explanation: a sample-size calculation estimates the amount of information that could be needed under specified assumptions; it is not evidence about the trial's observed statistical power. The planning assumptions described for this record use a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect set as a stated fraction of the observed effect. Any such illustration is a planning exercise, not a result from the trial and not the trial's own design justification. The registry record does not report the protocol's sample-size justification or establish that those assumptions governed trial planning. The registry entries do not include numerical planning estimates, so no planning total or per-arm requirement can be stated.
Over-dispersion is a general concern when observed variability exceeds what a statistical model assumes. For a continuous endpoint, unmodeled variability can make estimated uncertainty too small, while a suitable model or robust method may account for it. The registry does not report a variance estimate or model diagnostics for this outcome. It is therefore not possible to judge whether over-dispersion was relevant or how it was handled.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one secondary outcome: skin assessment on Ioban, ActiGard, and Steri-Drape 2 application sites, respectively. It also reports two outcome measures and zero analyses. The record does not explain how the measure count relates to the listed outcome or provide results for the secondary outcome. No hierarchy of primary and secondary hypotheses beyond the identified primary endpoint, and no multiplicity adjustment, are reported in the registry record.
General explanation: when several outcomes or statistical comparisons are examined, the chance of at least one apparently notable result can increase if each is interpreted independently. A prespecified testing hierarchy or multiplicity adjustment can address that issue, but the appropriate approach depends on the study's objectives and analysis plan. Since the registry does not report an inferential analysis or adjustment, it is not possible to assess how multiplicity was handled. The available arm summaries do not establish whether any formal testing was planned or performed.
Missing-data methods are not reported in the registry record. Although the primary outcome has arm-level summaries, the record does not provide participant-level completeness, reasons for missing measurements, imputation methods, or sensitivity analyses. The listed per-protocol population also lacks a definition and participant flow. Therefore, the posted means cannot establish whether all randomized participants were included or whether missingness could have affected the estimates.
General explanation: missing outcomes can affect estimates when the chance of a measurement being absent is related to participant characteristics or the unobserved measurement itself. Different assumptions about missingness may lead to different analyses. Without counts, reasons, and analysis procedures, readers cannot assess the extent or likely influence of missing data in this trial.
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 |
|---|---|---|---|
| ChloraPrep, DuraPrep | 0 | 22 | 0.0% |
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 |
|---|---|
| ChloraPrep, DuraPrep | 0 of 22 |
The registry groups the safety figures under “ChloraPrep, DuraPrep.” It reports 22 participants at risk for serious adverse events and 0 affected, and 22 at risk for other adverse events and 0 affected. These are the posted counts for the combined group label; the record does not provide separate safety counts by preparation. Deaths are not reported in the registry record.
These figures should be read as recorded event counts, not as proof that no adverse events of any kind occurred outside the categories or reporting captured in the registry. The record does not supply event-term detail for serious events, and no top serious-event terms are listed. It also does not describe how adverse events were collected, their observation period, or whether the safety population differed from the primary outcome population. The registry's zero affected counts apply to the categories and group as posted and should not be expanded into a broader safety conclusion.
General explanation: an observed count of zero does not show that the underlying risk is exactly zero. When a study has limited participant information, uncommon events may not be observed. Safety interpretation also depends on definitions, follow-up, and completeness of reporting, details that are not reported in the registry record. These figures therefore describe the posted safety counts without supporting conclusions beyond those counts.
12. What the Result Does, and Does Not, Mean
The posted results describe the mean peel force at 30 minutes for each preparation. The registry reports 78.6 grams-force for ChloraPrep, with a 95% confidence interval of 68.0 to 89.2, and 181.3 grams-force for DuraPrep, with a 95% confidence interval of 165.8 to 196.8. The means provide a descriptive comparison on the endpoint as defined in the record. The confidence intervals characterize the reported arm-specific estimates, subject to the interval method and assumptions, which are not specified.
The result does not provide a formal estimate or interval for the difference between preparations. No test or p-value for that comparison is reported, and the registry lists zero analyses. The displayed values should not be converted into an unreported contrast or treated as evidence of a prespecified statistical conclusion. Nor do they establish how consistent individual measurements were, because individual data and a measure of spread are not reported.
The endpoint captures peel force for a sample at the stated time. It does not by itself describe every property of drape adhesion, the performance of other products, or outcomes beyond the measurement. The registry lists skin assessment as a secondary outcome but does not post its results. The trial's stated population is Healthy, and the record does not report evidence from other populations or settings.
The design is randomized and parallel, but relevant implementation and analysis details remain unavailable in the registry record. Masking is listed as none, and the primary population is described as per protocol without a definition. The record does not reconcile enrollment with the arm-level sample counts or describe missing-data handling. These limits constrain interpretation of how the summaries relate to all randomized participants.
General explanation: statistical evidence and practical meaning are related but distinct. A precisely estimated measurement may still have uncertain implications for use, and an observed difference in means is not automatically a difference that matters clinically. The registry does not report a threshold for meaningful change or connect the peel-force endpoint to a clinical outcome. The posted results therefore describe a measured force comparison, not a recommendation or a conclusion about clinical benefit.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of the distinction between reporting arm summaries and reporting a comparative analysis. The registry provides a mean and 95% confidence interval for each preparation, but it does not provide a confidence interval or test for the contrast that corresponds to the randomized comparison. Readers need to distinguish the descriptive estimates from an inferential conclusion about the treatment contrast.
The endpoint is continuous, expressed in grams-force, and measured at 30 minutes. Reporting a mean and confidence interval gives a concise account of the average and its estimated precision. At the same time, the registry does not provide the underlying variability, individual observations, or details of the interval method. Those omissions illustrate why a confidence interval is most useful when its calculation and assumptions can be assessed alongside the estimate.
The record also makes analysis population and missingness important. It identifies a per-protocol analysis but does not define that population or explain participant flow. Enrollment is 22, while the arm summaries each report n 22.0; the record does not reconcile these counts. This prevents readers from tracing how randomized participants contributed to the endpoint summaries.
Finally, the trial has a listed secondary outcome, but no secondary results or analyses are posted. The record does not describe multiplicity handling or the statistical analysis plan. These features matter because transparent reporting allows readers to distinguish planned questions from exploratory summaries and to understand how uncertainty and multiple outcomes were addressed. In this case, the posted information supports a narrow description of the primary endpoint summaries while leaving important aspects of comparative inference undocumented.
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.
Several trial-specific limitations restrict interpretation of the posted outcome. The registry reports arm-specific means and confidence intervals but no direct comparison, p-value, or analysis model. It lists zero analyses, so the basis for any formal comparison is not available in the record. The method used to calculate the confidence intervals is also not reported.
The primary analysis is labeled per protocol, but the registry does not define eligibility for that population or report participant flow, exclusions, or reasons for exclusion. Enrollment is reported as 22, while both arm summaries list n 22.0; the record does not explain how these figures relate. Missing-data counts and handling are not reported, which prevents assessment of outcome completeness.
Although allocation is randomized and the model is parallel, the randomization procedure and allocation concealment are not reported. Masking is listed as none, but the registry does not specify who conducted or assessed the peel-force measurement. It also lacks detail on the measurement procedure and the variability of individual observations. The secondary skin-assessment outcome is listed without posted results or analysis details. The registry record does not report the protocol's sample-size justification, a prespecified analysis plan, or multiplicity handling.
These limitations concern what can be established from the registry record; they do not show that a particular procedure was or was not followed. The available summaries should be interpreted within the stated population, endpoint, and timeframe rather than generalized beyond what is recorded.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Compare Effect of Surgical Antiseptic Preparations on Incise Drape Adhesion to Skin — NCT01290978.
- Registry record last updated 2024-10-02; status last verified 2024-09.
- Results first posted 2013-03-05.
- 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
The registry describes a completed Phase 4, prospective randomized parallel comparison of ChloraPrep and DuraPrep, with masking listed as none. Enrollment is 22; the recorded study start is 2010-02 and primary completion is 2010-03. The primary endpoint is mean drape-removal peel force in grams-force at 30 minutes, analyzed per protocol. The registry reports arm means and 95% confidence intervals, but no direct comparative analysis. A secondary skin-assessment outcome is listed without posted results. Safety counts are reported under a combined group label, with 0 affected for serious adverse events and 0 affected for other adverse events; deaths are not reported in the registry record.