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 Abdominal Binder to Reduce Pain and Seroma Formation (NCT01673568), a randomized na study. The primary outcome is Visual Analog Scale of Pain Activity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01673568 |
| Phase | NA |
| Condition | Ventral Hernias |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 56 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Hvidovre University Hospital |
| Results posted | Yes |
2. Clinical Question
Population
Adults undergoing laparoscopic repair of ventral hernias, including umbilical or epigastric hernias, were the intended population. The registry record lists ventral hernias as the condition and reports enrollment of 56 participants. Further eligibility criteria and details of the participants enrolled are not reported in the registry record.
Intervention
The intervention was a postoperative abdominal binder. The study description says participants assigned to a binder wore it immediately after the operation, continuously during the day and night for 7 days. The listed device was an elastic ostomy belt.
Comparator
The comparison group received no abdominal binder. The registry record describes a randomized parallel-group comparison, with 28 participants listed in each arm for the primary endpoint.
Primary question
The primary endpoint asks whether self-reported pain during activity, measured with a Visual Analog Scale 24 hours after hernia repair, differed between participants assigned to an abdominal binder and those assigned to no binder. The posted group summaries are medians and full ranges; no statistical test result or estimate of between-group uncertainty is reported.
3. Trial Design
This was a randomized, controlled, parallel-group study comparing an abdominal binder with no abdominal binder after laparoscopic ventral hernia repair. The registry record reports enrollment of 56 participants, with 28 listed in each group for the primary pain endpoint. The study description calls the trial multi-center and investigator-blinded; the registry classifies masking as single. Who specifically was masked beyond the description of investigator blinding is not reported in the registry record.
The intervention description specifies that the binder was worn immediately after surgery, continuously during the day and night for 7 days. The comparator was no abdominal binder. The study planned follow-up for 30 days. Its stated primary aim included pain, discomfort, and quality of life, while seroma formation was registered as a secondary outcome. The posted primary endpoint result, however, is Visual Analog Scale pain during activity at 24 hours after repair.
The record lists the study as completed and gives a start in 2012-10 and primary completion in 2013-09. The sponsor is Hvidovre University Hospital. The planned minimum enrollment is described as 56, with the inclusion number said to be based on power calculations; the calculation assumptions and justification used by the investigators are not reported in the registry record. The trial phase is listed as not applicable. Details such as the randomization sequence method, allocation concealment, site count, participant eligibility criteria, and protocol deviations are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Abdominal Binder | no Abdominal Binder |
|---|---|---|
| STARTED | 28 | 28 |
| COMPLETED | 28 | 28 |
| NOT COMPLETED | 0 | 0 |
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: patiens were median 51 years, gender M:F=22:6.
| Characteristic | Unit | Abdominal Binder | no Abdominal Binder | Total |
|---|---|---|---|---|
| Participants analysed | 28 | 28 | 56 | |
| Age, Continuous | years | 51 (21 to 73) | 51 (31 to 71) | 51 (21 to 73) |
| Sex: Female, Male: Female | Participants | 6 | 6 | 12 |
| Sex: Female, Male: Male | Participants | 22 | 22 | 44 |
6. Primary Endpoint
The registry lists the primary outcome as Visual Analog Scale of Pain Activity, measured over 24 hours after hernia repair.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | units on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the Visual Analog Scale of Pain Activity, recorded 24 hours after hernia repair. Participants reported pain during activity on a scale where 0 means no pain in activity and 100 means the worst imaginable pain in activity. The endpoint therefore captures the participant's own assessment of pain in a specified context and at a specified postoperative time.
A self-reported pain scale is useful for measuring a symptom that is experienced by the participant and may not be fully represented by an observer's assessment. The activity framing distinguishes this measure from pain at rest. As a general statistical point, a single score is an imperfect summary of a subjective experience, and responses can vary between participants even when they receive the same care.
The registry reports the endpoint as a median with a full range for each arm. The abdominal-binder group has a median of 50 units, with a full range from 13 to 100. The no-binder group has a median of 70 units, with a full range from 11 to 97. These are descriptive summaries. The record does not report a confidence interval or a test result for the between-group comparison, so the summaries alone do not establish the precision of the comparison or whether it is statistically distinguishable from chance variation.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
At 24 hours after hernia repair, the posted median pain-during-activity score is 50 units in the abdominal-binder group and 70 units in the no-binder group. The reported full range is 13 to 100 in the binder group and 11 to 97 in the no-binder group. Both groups therefore include a broad span of reported scores, and the ranges overlap. These summaries describe the enrolled groups; they do not show each participant's score or how the scores are distributed between the endpoints of each range.
The group medians are descriptive statistics. They identify the middle of the ordered observations in each group, but they do not show how much uncertainty surrounds either median or the difference between groups. A full range reports the lowest and highest observed values. It is not a confidence interval, and it can be strongly affected by observations at the extremes. The registry record reports no confidence interval, standard error, p-value, or other inferential estimate for the primary comparison. No primary analysis result is posted in the record.
Consequently, the numerical summaries are not enough to judge the precision of the apparent separation between the medians. A confidence interval, as a general statistical concept, describes uncertainty in an estimated quantity under a specified analysis. For a treatment comparison, an interval around the between-group estimate would help readers assess which magnitudes of difference are compatible with the data and analysis. Such an interval is not reported in the registry record. The record also does not report the individual observations or a distributional summary beyond the median and full range.
The trial was randomized, which is intended to support a fair comparison of assigned groups, but the posted summaries cannot demonstrate whether randomization produced similar groups on relevant characteristics. Baseline characteristics are not reported in the registry record. The listed endpoint group sizes are 28 participants each, but the record does not explain whether every randomized participant contributed an endpoint measurement or how missing measurements, if any, were handled.
The study description says that pain, discomfort, and quality of life were among the aims, and it lists seroma formation as a secondary outcome. The primary result available in the record is specifically pain during activity at 24 hours. It should not be treated as a result for pain at other times, pain at rest, quality of life, discomfort, seroma, or the full 30-day follow-up. Results for those outcomes are not reported in the registry record. The group summaries also do not establish a causal conclusion by themselves: interpretation depends on the randomized comparison, outcome completeness, the prespecified analysis, and uncertainty estimates, several of which are not reported.
9. Statistical Methods Explained
The registry describes a randomized parallel-group study. In a randomized trial, assignment is intended to create groups that are comparable on average, including with respect to factors that were not measured. A parallel design means participants are assigned to one group and the groups are compared. The record identifies the groups as abdominal binder and no abdominal binder. It does not report how the random sequence was generated or how allocation was concealed before assignment, so those aspects of the design cannot be assessed from the registry record.
What the endpoint summaries say
The primary endpoint is a self-reported Visual Analog Scale score for pain during activity at 24 hours after repair. The scale is described as running from 0, no pain in activity, to 100, worst imaginable pain in activity. The registry reports a median and a full range for each arm. A median is the central ordered value: half of the observations are no higher and half are no lower, subject to ties and the convention used for an even number of observations. A range gives the observed minimum and maximum. It does not show whether most observations are close together or spread across much of the scale.
For the binder group, the median is 50 and the full range is 13 to 100. For the no-binder group, the median is 70 and the full range is 11 to 97. Reporting medians can be appropriate when an outcome is skewed or when a scale's distribution does not fit methods based on a normal distribution. The record does not provide the underlying scores or a distribution plot, so the shape of the pain-score distributions cannot be assessed from the summaries alone.
Rank-based methods in the study description
The brief study description mentions Mann-Whitney non-parametric statistics for seroma formation and a Friedman test for pain, discomfort, and quality of life. These are the methods named in that description, but the text is truncated and does not give a complete statistical analysis plan. The registry record does not report the test statistics, p-values, analysis estimates, or a complete account of how the tests were applied to the posted primary endpoint.
As a general explanation, the Mann-Whitney test compares the ranks of observations in two independent groups. It can be useful when a comparison is based on ordered outcomes or when normal-distribution assumptions are not suitable. It does not automatically test a difference in medians in every situation; its interpretation depends on the distributions in the groups. A Friedman test is a rank-based method for related or repeated measurements. The registry's brief description does not specify the measurement occasions or the detailed repeated-measures analysis, so the intended implementation cannot be reconstructed from the record.
Uncertainty and statistical evidence
Statistical inference requires more than comparing two descriptive medians. An estimate of the between-group contrast, together with an uncertainty interval or a test result, would show how compatible the observed data are with a range of possible underlying effects under a stated model. A confidence interval is a general tool for expressing uncertainty around an estimate; its width depends on the data and analysis. No such interval or test result for the primary comparison is reported in the registry record. The record lists no posted analyses, so a statistical significance claim cannot be made from the registered summary alone.
Non-parametric methods are often described as distribution-free, but that does not mean they require no assumptions. They still rely on an appropriate study design, independent or appropriately paired observations, and a clear definition of the target comparison. If observations are repeated within participants, the analysis must account for that relationship. Details necessary to evaluate those assumptions are not reported in the registry record.
Planning and power
The study description says a minimum of 56 participants was intended and that the inclusion number was based on power calculations. The calculation details, including the assumed effect, variability, and target power, are not reported in the registry record. The record's enrollment is 56. A planning calculation is not the same as an analysis of the observed data. In general, power describes the probability that a planned test will detect an effect of a specified size under stated assumptions; it does not measure the probability that a finding is true. Retrospective calculations based on an observed effect are not observed power and do not replace an estimate with an uncertainty interval. No investigator sample-size calculation is available to assess whether the planned enrollment was adequate for this endpoint.
Over-dispersion is a general concern when count outcomes vary more than a chosen model expects; ignoring it can make uncertainty estimates too small. The primary endpoint is a pain scale rather than a count, and the registry does not report a model-based count analysis for this endpoint. For seroma, ultrasound measurement is mentioned in the study description, but detailed outcome values and analyses are not reported in the registry record. The available information is therefore insufficient to assess the distribution, model, or precision of a seroma comparison.
10. Multiplicity, Missing Data and Analysis Populations
The study description names several outcomes of interest: pain, discomfort, quality of life, and seroma formation. The record identifies Visual Analog Scale pain during activity at 24 hours as the primary endpoint and lists seroma formation as a secondary outcome. It does not provide a complete hierarchy of all outcomes and time points, identify which analyses were prespecified as confirmatory, or describe an adjustment for multiple comparisons. Whether and how multiplicity was handled is not reported in the registry record.
Multiplicity matters in general when several outcomes, time points, or subgroup comparisons are tested. As the number of analyses grows, the chance of at least one apparently notable result can increase. A prespecified primary endpoint can help focus interpretation, but it does not reveal how other analyses were selected or interpreted. The record lists no posted analyses, so multiplicity procedures cannot be evaluated.
The record gives 28 participants per group for the primary endpoint summaries and 56 enrolled overall. It does not report the number randomized separately from the number enrolled, a flow of participants through follow-up, endpoint-specific missingness, reasons for missing data, or an imputation method. The analysis population is also not described: it is not reported whether the summaries include all randomized participants, only participants with observed endpoint data, or another group. Thus, the effect of missing observations and the handling of participants who did not follow their assignment cannot be assessed.
As a general principle, complete-case analyses can be biased if the likelihood of missing data is related to outcome or treatment assignment. Other missing-data methods also rely on assumptions that should be described. The registry record does not report enough information to determine whether missing data occurred or how it was addressed.
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 |
|---|---|---|---|
| Abdominal Binder | 0 | 28 | 0.0% |
| no Abdominal Binder | 0 | 28 | 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 |
|---|---|
| Abdominal Binder | 0 of 28 |
| no Abdominal Binder | 0 of 28 |
The registry record lists zero serious adverse events among 28 participants in the abdominal-binder group and zero among 28 participants in the no-binder group. It also lists zero other adverse events among 28 participants in each group. Death counts are not reported in the registry record. These figures are counts recorded for the groups; they are not a guarantee that no events occurred outside the reporting captured by the record.
A zero count does not establish that an event is impossible or that the intervention has no safety risks. When event counts are absent, the data provide limited information about how frequently uncommon events might occur. Interpretation also depends on how events were defined, collected, monitored, and reported, as well as the period during which participants were observed. The registry record does not describe those details or provide event terms beyond the zero counts.
The study description says participants were followed for 30 days, but the adverse-event reporting period and completeness are not specified. The posted counts therefore should be read as the record's reported figures, not as a comprehensive safety assessment. They also do not support a comparison of safety between groups beyond noting the counts reported for each arm.
12. What the Result Does, and Does Not, Mean
The posted primary endpoint summaries describe self-reported pain during activity 24 hours after hernia repair. The binder group has a median score of 50, and the no-binder group has a median score of 70. The full ranges are 13 to 100 and 11 to 97, respectively. These figures give a descriptive view of the observed scores but not a complete estimate of the between-group effect or its uncertainty.
The summaries do not establish whether the observed difference between group medians is statistically distinguishable from random variation. No test result, confidence interval, or adjusted estimate is reported in the registry record. Nor do the summaries indicate the probability that any particular participant experienced a given level of pain. Individual outcomes and the distribution of scores within each group are not reported.
The primary endpoint concerns pain during activity at a single time point. It does not directly answer questions about pain at rest, pain at other times, discomfort, quality of life, seroma formation, or outcomes across the entire follow-up. Although the study description identifies these broader topics, corresponding results are not reported in the registry record.
Random assignment is an important design feature for comparing groups, but the record lacks information about participant flow, baseline characteristics, missing data, and the analysis population. Those details matter when judging how the reported summaries relate to the randomized comparison. The study description says the target enrollment was based on power calculations, but the assumptions and calculations are not reported, so the rationale for the planned enrollment cannot be evaluated.
The findings should therefore be understood as descriptive posted results from a completed randomized study, rather than a complete inferential analysis. They neither establish that a binder changes pain nor establish that it has no effect. The evidence available in the registry record is limited to the reported group summaries and does not include the statistical results needed to quantify uncertainty in the comparison.
13. Why This Trial Matters Statistically
This trial illustrates the distinction between a randomized design and a fully reported statistical comparison. Random allocation can support causal interpretation by reducing systematic differences between groups on average, but readers still need to know who contributed outcome data, how outcomes were analyzed, and how uncertain the estimated comparison is. The registry record identifies a randomized parallel-group study and posts group summaries, but it does not include an inferential analysis for the primary endpoint.
The endpoint is a patient-reported pain score. Such outcomes are important statistical examples because they are bounded, ordered measurements that may have skewed distributions and substantial variation between individuals. Reporting medians and full ranges can describe the center and extremes without assuming a normal distribution. At the same time, those summaries do not show the full distribution or provide a confidence interval for the treatment contrast.
The study description also mentions several related outcomes and a planned follow-up period. This raises general questions about prespecification and multiplicity: readers need to distinguish the designated primary question from secondary outcomes and additional time points. The registry record identifies a primary measure and lists seroma as secondary, but it does not provide a full analysis plan or multiplicity approach.
Finally, the record says the enrollment target was based on power calculations but does not report the assumptions behind them. This is a useful reminder that a sample-size justification is interpretable only when its target effect, variability assumptions, and analysis are available. The posted record makes clear what comparison was intended and what descriptive pain summaries were reported, while leaving important aspects of precision and analysis 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.
The posted statistical information is limited. The primary endpoint has group medians and full ranges, but no confidence interval, test result, p-value, or estimated between-group contrast is reported in the registry record. The available summaries therefore do not quantify the precision of the comparison. Individual participant results and fuller distributional descriptions are also not reported.
The trial description and registry fields differ in specificity about masking: the registry classifies the study as single-masked, while the brief description calls it investigator-blinded. The identity of any other masked parties and the practical masking procedures are not reported. Details of sequence generation and allocation concealment are likewise not reported in the registry record.
Participant flow and the analysis population are not described. Although 28 participants are listed in each arm for the primary result and total enrollment is 56, the record does not explain whether all randomized participants contributed data, whether any endpoint measurements were missing, or how deviations from assigned treatment were handled. Baseline characteristics are not reported, limiting assessment of the groups after randomization.
The study description states that follow-up was planned for 30 days and identifies discomfort, quality of life, and seroma as additional outcomes, but results for these outcomes are not reported in the registry record. The primary result is limited to pain during activity at 24 hours. The full statistical analysis plan, outcome hierarchy, multiplicity handling, and detailed sample-size calculation are also not reported. These omissions constrain assessment of how completely the posted summaries represent the planned study questions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Abdominal Binder to Reduce Pain and Seroma Formation — NCT01673568.
- Registry record last updated 2014-06-09; status last verified 2014-05.
- Results first posted 2014-06-09.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a completed randomized parallel-group trial sponsored by Hvidovre University Hospital, with 56 participants enrolled. It compares a postoperative abdominal binder with no binder after laparoscopic ventral hernia repair. The study description specifies continuous binder use for 7 days and planned follow-up for 30 days.
The posted primary endpoint is self-reported pain during activity on a Visual Analog Scale 24 hours after repair. The binder group has a median of 50 and a full range of 13 to 100; the no-binder group has a median of 70 and a full range of 11 to 97. The record does not report an inferential comparison for this endpoint. Seroma formation is listed as a secondary outcome, but its results are not reported in the registry record.
The record also lists zero serious and zero other adverse events in each group. Details of participant flow, missing data, analysis populations, and the full statistical plan are not reported.