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 Evaluating the Cost-effectiveness, Efficacy, Safety and Tolerance of Mepilex® Ag Versus Silvadene® (NCT00742183), a randomized na study. The primary outcome is Compare the Costs of Using the Interventions (Direct and Indirect).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00742183 |
| Phase | NA |
| Condition | Second Degree Burn |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 100 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Molnlycke Health Care AB |
| Results posted | Yes |
2. Clinical Question
Population
People with second-degree, or partial-thickness, burns were the population of interest. The registry describes an intention-to-treat population comprising patients who received at least one post-randomisation treatment and provided some data for the primary endpoint. Further details of eligibility and participant characteristics are not reported in the registry record.
Intervention
The intervention was Mepilex® Ag, described as an antimicrobial soft silicone foam dressing. Its components include a soft silicone wound contact layer, an absorbent polyurethane foam pad containing a silver compound and activated carbon, and a vapour-permeable waterproof film.
Comparator
The comparator was Silvadene® Cream 1%, a topical antimicrobial drug containing silver sulfadiazine. The registry describes it as an adjunct for preventing and treating wound sepsis in patients with second- and third-degree burns.
Primary question
The primary objective was to compare direct and indirect costs and benefits, including healing outcomes and quality of life, from the health care provider perspective. The registered cost-effectiveness measure was the incremental cost-effectiveness ratio: the difference in total costs divided by the difference in the rate of full re-epithelialization at 20 days, taken from the survival curve. The posted primary results give mean costs by arm, but not the numerical ratio or the healing-rate contrast needed to interpret it.
3. Trial Design
This was a randomized, open-label, parallel-group, comparative, multicentre investigation conducted in the US. The registry lists an enrollment of 100 and marks the study completed. The recorded start was 2008-08, and primary completion was 2009-10. The primary-outcome timeframe is August 2008-August 2009. The listed phase is NA.
The two arms were Mepilex Ag and Silvadene. The posted mean-cost results are based on 49 participants in the Mepilex Ag arm and 51 in the Silvadene arm. These are the group counts attached to the outcome results; they should not be treated as additional information about how the registry defined or handled every participant in the analysis.
Random allocation is recorded, while masking is listed as none. In general, random allocation is intended to balance prognostic factors between groups, although it does not ensure that every relevant characteristic is balanced in a particular trial. With no masking, participants and study personnel may know which treatment is being used. That can matter for outcomes influenced by reporting, clinical decisions, or how care and resource use are recorded. The registry does not report further details of allocation concealment or the practical arrangements for assigning treatment.
The registry names cost-effectiveness, efficacy, safety, and tolerance as study aims. Its registered primary outcome concerns costs and an incremental cost-effectiveness ratio; the displayed primary results are mean costs by group. No secondary outcome results are posted in the registry record. Further information on the planned sample-size justification, trial statistical plan, or interim analyses is not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Mepilex Ag | Silvadene |
|---|---|---|
| STARTED | 49 | 51 |
| COMPLETED | 40 | 39 |
| NOT COMPLETED | 9 | 12 |
Reasons for not completing this period:
| Reason | Mepilex Ag | Silvadene |
|---|---|---|
| Adverse Event | 2 | 2 |
| Death | 1 | 0 |
| Physician Decision | 0 | 2 |
| Lost to Follow-up | 4 | 4 |
| Required skin-graft | 1 | 1 |
| Withdrawal by Subject | 1 | 0 |
| Lack of Efficacy | 0 | 3 |
Analysis population for the primary outcome, as defined in the registry: Primary analysis: the Intention To Treat (ITT) population will include all patients subject to at least one post-randomisation treatment and that provide some data for the primary endpoint. If there are any patients included which do not comply with the inclusion/exclusion criteria they will be included in the ITT population
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.
| Characteristic | Unit | Mepilex® Ag | Silvadene® Cream 1% | Total |
|---|---|---|---|---|
| Participants analysed | 49 | 51 | 100 | |
| Age, Categorical: <=18 years | Participants | 4 | 4 | 8 |
| Age, Categorical: Between 18 and 65 years | Participants | 41 | 41 | 82 |
| Age, Categorical: >=65 years | Participants | 4 | 6 | 10 |
| Age, Continuous | years | 37.0 (SD 18.1) | 39.2 (SD 18.2) | 38.4 (SD 18.2) |
| Sex: Female, Male: Female | Participants | 13 | 10 | 23 |
| Sex: Female, Male: Male | Participants | 36 | 41 | 77 |
| Region of Enrollment: United States | participants | 49 | 51 | 100 |
6. Primary Endpoint
The registry lists the primary outcome as Compare the Costs of Using the Interventions (Direct and Indirect), measured over August 2008-August 2009.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | dollars |
| Endpoint classification | Continuous Endpoint |
The registered primary endpoint concerns the costs of using the two interventions, expressed in dollars. The registry describes total costs as including primary and secondary dressings, silver sulfadiazine cream, estimated application, labor, supplies, and pain medications. These costs were estimated from a representative sample of each population across study facilities using activity-based costing methods. The stated perspective is that of the health care provider, and the primary timeframe is August 2008-August 2009.
The intended cost-effectiveness measure is an incremental cost-effectiveness ratio. It relates the difference in total costs between groups to the difference in the rate of full re-epithelialization at 20 days, with the healing rate taken from the survival curve. In general, this kind of ratio expresses the additional cost associated with a difference in a health outcome; it is intended to inform decision makers considering the value they place on that outcome.
The posted primary results give group mean costs and 95% confidence intervals. They do not report a numerical incremental ratio or the healing-rate contrast used in its denominator. Therefore, the cost estimates can be described, but the registered cost-effectiveness comparison cannot be reconstructed from the posted primary results alone. Quality of life is named as a benefit of interest, but no quality-of-life result is posted in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted mean cost is 395.0 dollars for Mepilex Ag, with a 95% confidence interval from 343.7 to 450.3. For Silvadene, the posted mean is 775.8 dollars, with a 95% confidence interval from 659.4 to 892.2. These estimates describe the mean costs reported for the two groups; they do not by themselves give the incremental cost-effectiveness ratio.
The registry defines that ratio as the difference in total costs divided by the difference in full re-epithelialization rates at 20 days, with the rates taken from a survival curve. No numerical healing-rate contrast or incremental ratio is reported in the registry record. Without the outcome contrast, the cost means alone cannot establish the additional cost associated with a healing benefit or how that ratio should be judged. The ratio’s interpretation also depends on the direction and size of the health-outcome difference.
A confidence interval describes uncertainty around an estimate under the assumptions of the analysis that produced it. It is not a range containing every participant’s cost, and it does not show the distribution of individual costs. The registry does not state the method used to calculate these intervals. The intervals are reported for each group separately; no interval for the between-group cost contrast is posted. The interval endpoints therefore should not be used as a substitute for a directly reported comparative estimate or test.
The numerical group means are lower for Mepilex Ag than for Silvadene in the posted results. That descriptive ordering is not, on its own, evidence about the precision or statistical significance of the difference. Nor does it answer the primary cost-effectiveness question, because the registered measure combines costs with a healing outcome. The posted cost estimates should be read as cost results rather than as a complete assessment of efficacy, quality of life, or overall value.
The registry lists an open-label, randomized design and reports the group means and confidence intervals. It does not report a detailed analysis plan, a between-group statistical test for these costs, or a numerical healing outcome in the primary results. Any interpretation should therefore stay close to what is posted: mean costs were reported for each arm, while the comparative cost-effectiveness result remains unquantified in the registry record.
9. Statistical Methods Explained
The primary outcome is continuous: costs are recorded in dollars, and the registry specifies that the reported summary is a mean. A mean describes the arithmetic average on the measurement scale. For costs, it can be influenced by participants with unusually high resource use, so a mean may not describe the experience of a typical participant when costs are strongly skewed. The registry does not report the distribution of costs or additional summaries that would show how spread or skewed the observed costs were.
What do the confidence intervals express?
The registry gives 95% confidence intervals for each arm’s mean cost. In general, a confidence interval conveys the precision of an estimate under the assumptions and method used to construct it. A narrower interval indicates greater precision than a wider interval on the same scale, while an interval is not a prediction range for individual observations. The calculation method is not reported in the registry record, so the interval values can be quoted, but the particular statistical assumptions behind them cannot be assessed from the record.
The two posted intervals describe separate group means. A direct comparison requires an estimate of the difference between groups and uncertainty around that difference, or another suitable comparative analysis. The registry does not post a confidence interval or test for the between-group cost difference. The separate intervals should not be treated as if they were such a comparison. In general, overlap or non-overlap of separate confidence intervals is not a replacement for an explicitly estimated contrast.
How does the registered cost-effectiveness measure work?
The registry defines the incremental cost-effectiveness ratio as the difference in total costs divided by the difference in the rate of full re-epithelialization at 20 days. The rate is described as coming from the survival curve. In general, a ratio of this form combines a cost contrast with an outcome contrast, and its meaning depends on both. A cost difference without the corresponding outcome difference is insufficient to calculate or interpret the ratio. The posted primary results report group mean costs, but the numerical ratio and healing-rate contrast are not reported in the registry record.
The registry describes total costs as covering primary and secondary dressings, silver sulfadiazine cream, estimated application, labor, supplies, and pain medications. It states that these costs were estimated from a representative sample of each population across study facilities using activity-based costing. This approach assigns costs to activities involved in care. The registry does not give further detail on how the representative samples were selected, how quantities or unit costs were obtained, or how uncertainty in the cost estimates was handled.
What does randomization contribute?
Random allocation is recorded, with a parallel-group design. In general, randomization aims to make treatment assignment independent of participant characteristics, helping support a fair comparison of outcomes between groups. It does not remove uncertainty from the results or guarantee balance in every characteristic. The record does not provide details of sequence generation, allocation concealment, or the statistical adjustment, if any, used in the primary analysis.
The study is listed as open-label, with masking recorded as none. In general, knowledge of assigned treatment can affect subjective assessments, participant-reported outcomes, clinical decisions, or measurement of resource use. Whether and how such influences were addressed is not reported in the registry record. The outcome includes costs estimated through activity-based methods, but no further procedures to reduce the influence of treatment knowledge are described.
What can be concluded from the posted analyses?
The primary results give means and confidence intervals for costs in the two arms. The registry lists one outcome measure and no posted analyses. It does not report a comparative test, a detailed statistical model, handling of skewed cost data, or a method for combining cost and healing uncertainty. In general, cost data may be over-dispersed or skewed, meaning their variability can be large relative to their mean and conventional modelling assumptions may not fit well. Whether that was assessed or addressed in this trial is not reported in the registry record.
The registry describes the intention-to-treat population as including patients subject to at least one post-randomisation treatment and providing some data for the primary endpoint. That wording is available, but further details of the final analysis population and missing-data procedures are not reported in the registry record. Consequently, the posted summary statistics can be described, while the full analysis process and its assumptions cannot be independently evaluated from the registry record alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and posts no secondary outcome results. It does not report whether multiple outcomes, time points, or statistical comparisons were tested as part of a broader analysis. A multiplicity adjustment, or a decision not to adjust, is not reported in the registry record. It is therefore not possible to determine from the record how the possibility of chance findings across multiple analyses was handled.
The primary population description refers to an intention-to-treat population including patients who received at least one post-randomisation treatment and provided some data for the primary endpoint. The description also begins to address patients who might not comply with inclusion or exclusion criteria, but the registry wording is incomplete. The full population rules and the number of participants included in the final primary analysis are not reported in the registry record.
The record does not describe how missing endpoint data were handled, whether any imputation was used, or whether sensitivity analyses were conducted. It also does not state whether the posted means and confidence intervals use the same analysis population or how any exclusions were treated. These omissions matter because missingness and analysis-population choices can affect the estimates and their interpretation. The reported group means remain descriptive of the posted results, but the registry record does not provide enough information to assess the robustness of the primary analysis to missing data or alternative population definitions.
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 |
|---|---|---|---|
| Mepilex Ag | 2 | 49 | 4.1% |
| Silvadene | 1 | 51 | 2.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Mepilex Ag | 20 of 49 |
| Silvadene | 26 of 51 |
Most frequent serious adverse event terms
| Event term | Organ system | Mepilex Ag | Silvadene |
|---|---|---|---|
| Death | General disorders | 1 of 49 | 0 of 51 |
| Pain | General disorders | 0 of 49 | 1 of 51 |
| Anticoagulation drug level above therapeutic | Investigations | 1 of 49 | 0 of 51 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Mepilex Ag | Silvadene |
|---|---|---|---|
| Nausea | Gastrointestinal disorders | 8 of 49 | 10 of 51 |
| Pruritus | Skin and subcutaneous tissue disorders | 6 of 49 | 12 of 51 |
| Constipation | Gastrointestinal disorders | 5 of 49 | 7 of 51 |
| Dyspepsia | Gastrointestinal disorders | 3 of 49 | 4 of 51 |
| Skin graft | Surgical and medical procedures | 2 of 49 | 4 of 51 |
| Staphylococcal infection | Infections and infestations | 4 of 49 | 1 of 51 |
| Hypertension | Vascular disorders | 3 of 49 | 0 of 51 |
Serious events with the highest arm-level rate: death (2.0%), anticoagulation drug level above therapeutic (2.0%), pain (2.0%).
The registry reports serious adverse events affecting 2 participants in the Mepilex Ag group and 1 in the Silvadene group. It separately reports other adverse events affecting 20 participants in the Mepilex Ag group and 26 in the Silvadene group. The corresponding group counts at risk are 49 and 51, respectively. These are reported counts, not a formal comparative safety analysis.
The registry also lists Death, Anticoagulation drug level above therapeutic, and Pain among the top serious adverse-event terms, each shown as 2.0%. It does not identify the group for these terms in the posted listing or explain how the term percentages relate to the group-level counts. The group-level deaths field is not populated. Accordingly, the listed Death term and the unpopulated group-level deaths field should be reported as separate elements of the record, not reconciled by inference.
In general, adverse-event counts do not by themselves establish that one intervention caused an event or that the observed groups differ meaningfully in safety. The registry does not report additional detail on event severity beyond the serious-event designation, timing, relatedness, or a comparative statistical analysis. The figures should therefore be read as the adverse-event information recorded, with those limitations.
12. What the Result Does, and Does Not, Mean
The posted results establish that mean costs were reported separately for Mepilex Ag and Silvadene, with a 95% confidence interval for each mean. Numerically, the Mepilex Ag mean is lower than the Silvadene mean in the registry results. The registry also describes what cost categories were included and identifies the health care provider perspective. These features make the posted figures useful as a record of the trial’s reported cost estimates.
They do not establish which intervention is more cost-effective. The registered cost-effectiveness ratio requires both a cost contrast and a contrast in full re-epithelialization rates at 20 days. The numerical ratio and the healing-rate contrast are not reported in the registry record. The cost means alone cannot indicate the health benefit associated with any cost difference or show whether a decision maker’s willingness to pay would favor one option.
The posted results also do not provide a numerical quality-of-life comparison or secondary outcome analysis. While safety counts are reported, the record does not present a full comparative safety analysis. The study’s objectives include efficacy, safety, and tolerance, but those aims should not be mistaken for posted evidence on each outcome.
In general, a trial estimate is interpreted in light of its precision, analysis methods, population, and outcome measurement. Here, the group confidence intervals describe uncertainty around each mean under methods that the registry does not detail. No comparative cost interval or test is posted. The results should therefore be understood as reported group cost summaries, not as a complete answer to the combined cost-and-healing question. They do not by themselves establish causation, generalizability to populations or settings not described in the record, or a treatment recommendation.
13. Why This Trial Matters Statistically
This trial is statistically notable because its primary question is not simply whether the mean cost differs between groups. The registry defines the main cost-effectiveness quantity as a ratio linking the cost difference to a difference in full re-epithelialization rates at 20 days. That distinction matters: a cost contrast is only one component of a cost-effectiveness result, and an economic conclusion depends on the health outcome being compared as well.
The registry’s posted primary results give arm-specific mean costs and confidence intervals, while the numerical incremental ratio and healing-rate contrast are not reported. This illustrates why a result should be interpreted in relation to its registered estimand: the outcome the analysis is intended to quantify. When the posted numerical results do not include every component of that estimand, the available summaries cannot fully answer the registered question.
The study also combines clinical and resource-use considerations. Its cost categories include dressings, cream, application, labor, supplies, and pain medications, and the estimates are described as activity-based costs from a representative sample across study facilities. Such costing choices define what the reported mean represents. In general, different cost components, costing methods, and perspectives can produce different economic estimates, so clear reporting is important for interpretation.
Finally, the open-label design and limited statistical details in the registry make it useful to distinguish reported details from unanswered methodological questions. Randomization is recorded, but further details of the analysis plan, missing-data handling, and comparative uncertainty are not reported in the registry record. A careful statistical reading preserves the information the registry does provide without treating the cost means as a complete clinical or economic verdict.
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 does not report a numerical incremental cost-effectiveness ratio or the full re-epithelialization contrast at 20 days that the ratio requires. This prevents direct interpretation of the registered primary economic measure from the posted primary results. The group mean costs and their confidence intervals are available, but no interval or test for the between-group cost contrast is reported.
The statistical methods are incompletely described in the registry record. The method used to calculate the confidence intervals, the distribution of individual costs, any adjustment for skewness, and any comparative model are not reported. The registry also does not detail the cost-sampling process beyond describing a representative sample across study facilities and activity-based costing.
The record lists the study as open-label and does not report how awareness of treatment assignment was addressed when collecting cost or outcome information. Details of allocation concealment, eligibility criteria, participant characteristics, and the final analysis population are not reported in the registry record. Missing-data methods, sensitivity analyses, multiplicity procedures, and interim analyses are also not reported.
Although the study objectives include healing, quality of life, safety, and tolerance, the registry posts no secondary outcome results. The adverse-event information is limited to group counts and a list of top serious terms, without a detailed comparative analysis. These limitations constrain what can be concluded from the registry results and should not be filled in by assumptions about the study protocol or analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluating the Cost-effectiveness, Efficacy, Safety and Tolerance of Mepilex® Ag Versus Silvadene® — NCT00742183.
- Registry record last updated 2017-12-08; status last verified 2017-11.
- Results first posted 2010-11-19.
- 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 record describes a completed, randomized, open-label, parallel, multicentre US investigation of Mepilex® Ag versus Silvadene® for partial-thickness burns. Enrollment is listed as 100; the posted primary cost results include 49 participants in the Mepilex Ag group and 51 in the Silvadene group.
The primary objective concerns direct and indirect costs and benefits from the health care provider perspective. The registered economic measure is an incremental cost-effectiveness ratio based on costs and full re-epithelialization at 20 days. Posted primary results report mean costs of 395.0 dollars for Mepilex Ag and 775.8 dollars for Silvadene, with group-specific 95% confidence intervals. The numerical ratio and healing-rate contrast are not reported in the registry record.
The registry reports serious and other adverse-event counts, but no secondary outcome results or analyses. Further details on statistical methods, missing data, and multiplicity are not reported in the registry record.