Pre-hospital Advanced Therapies for Control of Hemorrhage - Pelvis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pre-hospital Advanced Therapies for Control of Hemorrhage - Pelvis (NCT02855060), a randomized na study. The primary outcome is Mortality Rate.

2. Clinical Question

3. Trial Design

PATCH-Pelvis, registered as NCT02855060, was a randomized, parallel-group study with no masking. The registry lists Wake Forest University Health Sciences as sponsor and an enrollment of 50. The record lists the phase as NA. The study status is completed; the recorded start was 2016-07 and primary completion was 2018-06.

Participants were assigned to a pelvic-binder group or a no-binder group. The binder was described as a commercially available device used to stabilize the pelvis, while the no-binder group was described as receiving standard of care. Because masking was listed as none, the design was open-label. The registry record does not report further information about randomization procedures, allocation concealment, participating sites, or treatment adherence.

The primary outcome was mortality within 30 days of presentation. The posted outcome counts use denominators of 20 participants in the pelvic-binder group and 23 in the no-binder group. These are the denominators associated with the posted primary outcome, rather than the registry's overall enrollment figure. The record does not explain why the primary outcome denominators differ from the enrollment figure or describe the analysis population used.

The registry lists secondary outcomes concerning pain scores, skin complications after binder application, hospital length of stay, and blood transfusions. Numeric secondary results are posted for the blood-transfusion outcome within 48 hours. Numeric results for the other listed secondary outcomes are not reported in the registry record. Further details about the protocol and statistical analysis plan are also 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

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Mortality Rate, measured over 30 day.

The primary endpoint was mortality within 30 days of presentation, recorded as a count of participants. The registry describes the outcome as the percentage of patients who experienced mortality during that timeframe and states that it would be compared between the two study arms. Death is a clinically important outcome and provides a direct, patient-level measure for this comparison. The timeframe also defines which deaths are included in the primary outcome; deaths beyond 30 days are not part of the stated endpoint.

The posted results list 0 deaths among 20 participants assigned to a pelvic binder and 1 among 23 assigned to no binder. These counts are the direct observations; the group comparison is an estimate based on those observations. With very few events, a small change in the observed counts could substantially change the estimated difference. The interpretation therefore depends not only on the point estimate, but also on the confidence interval and the limitations of the available data.

The endpoint is distinct from the other outcomes named in the registry, which include pain, skin complications, hospital length of stay, and transfusion. The record does not report the precise operational definitions or ascertainment procedures for the primary endpoint beyond its 30-day timeframe and participant-count description.

7. Results Posted in the Registry

• No Binder: 4.3% (1/23) versus 0.0% (0/20) on control; risk difference 4.3 percentage points (95% CI -4.0 to 12.7); unadjusted two-proportion z-test p = 0.345.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Number of Patients With Blood Transfusions

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • No Binder: 21.7% (5/23) versus 5.0% (1/20) on control; risk difference 16.7 percentage points (95% CI -2.6 to 36.1), risk ratio 4.35 (0.55–34.17); unadjusted two-proportion z-test p = 0.114.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between No Binder and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists several secondary outcome domains, but numeric results are posted for the blood-transfusion outcome within 48 hours. Numeric findings for the other listed secondary outcomes are not reported in the registry record. The available secondary information therefore provides only a partial view of the outcomes named for the trial, rather than a broad account of pain, complications, hospital stay, and transfusion together.

The primary outcome concerns mortality by 30 days, while the posted secondary comparison concerns transfusion within 48 hours. These outcomes measure different aspects of the clinical course and use different timeframes. A secondary finding cannot substitute for the primary endpoint, and a pattern in one outcome does not automatically imply the same pattern for another. The posted secondary data do not resolve the uncertainty in the mortality comparison.

The secondary result should be read cautiously because it is one of multiple outcome domains listed by the registry and is reported as an unadjusted comparison. When several outcomes are examined, the chance of observing apparently notable results by chance can increase. General statistical reasoning: accounting for multiple comparisons can change how much weight is placed on individual secondary p-values. Whether the study used a prespecified multiplicity strategy is not reported in the registry record. The record also lists no reported analyses for the secondary results.

The secondary results can contribute descriptive information, but they do not provide a basis for broad conclusions across all listed outcomes. The number of posted secondary measures, missing analytic detail, and multiplicity considerations all constrain interpretation. In particular, the registry record does not provide enough information to determine whether the reported secondary outcome was selected from a larger set of analyses or how it was prioritized in the study's analysis plan.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Pain Scores - Visual Analog Scale
• Number of Participants With Skin Complications After Pelvic Binder Application
• Length of Stay in Hospital
• Number of Patients With Blood Transfusions

9. Statistical Interpretation

10. Statistical Methods Explained

The main comparison is between two randomized groups: pelvic binder and no binder. The primary endpoint is binary at the participant level: each participant either experienced mortality within 30 days or did not. The registry presents the outcome as participant counts and reports a risk difference for the comparison. A risk difference expresses the difference between the groups' event risks, with the comparison oriented as no binder relative to pelvic binder. A positive estimate in that orientation indicates a higher observed risk in the no-binder group; it does not by itself establish a real or causal difference.

What does the confidence interval contribute?

A confidence interval describes the statistical uncertainty around an estimated effect under the method used to construct it. It is not a range containing a fixed proportion of individual outcomes, and it is not a guarantee that the true effect lies within its bounds. For the primary comparison, the interval crosses zero. Zero is the value representing no risk difference. Thus the interval includes the possibility of no difference as well as values on either side. The interval is wide relative to the sparse event information, which limits precision.

The interval and the point estimate answer related but distinct questions. The point estimate gives the central estimated direction and magnitude; the interval conveys how uncertain that estimate is. With so few mortality events, the point estimate should not be treated as a stable measure of the size of any underlying effect. The exact interval-construction method is not reported in the registry record.

How should the p-value be read?

The unadjusted primary p-value is 0.345. A p-value measures the compatibility of the observed data with a statistical null hypothesis under a specified model and testing procedure. A larger p-value does not prove that there is no effect, and a smaller p-value would not by itself show that an effect is important. The testing method, model details, and any adjustment strategy are not reported in the registry record. The p-value should therefore be considered alongside the estimate, interval, event counts, and reporting limitations rather than treated as a standalone conclusion.

The comparison is labeled unadjusted. In general, an unadjusted comparison does not account for other variables through a multivariable model. Whether adjusted analyses were planned or conducted is not reported in the registry record. The registry reports no analyses for the primary outcome. Consequently, the posted numerical comparison is the available basis for describing the primary result, but the analysis details behind it cannot be fully reconstructed from the record.

Why do sparse events matter?

When an endpoint occurs rarely, a small number of events carries much of the information about the comparison. General statistical reasoning: estimates based on sparse events are often sensitive to individual observations and tend to have substantial uncertainty. Here, one group has no posted deaths and the other has one. That pattern gives a direction to the observed comparison, but it does not provide enough event information for a precise estimate. The confidence interval crossing zero reflects that uncertainty.

The outcome counts and group denominators are also important to distinguish. The counts describe events, while denominators describe participants included in the posted group outcome. The registry's enrollment is 50, whereas the primary outcome denominators are 20 and 23. The record does not explain this difference, and the reason should not be inferred from the counts alone. The analysis population, participant flow, and handling of missing outcome data are not reported in the registry record.

What does the secondary planning illustration mean?

The registry includes a planning illustration associated with the blood-transfusion comparison. It uses the observed effect as a reference and considers planning for stated fractions of that observed effect. It assumes a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. The resulting sample sizes are planning illustrations, not observed trial results and not an estimate of the trial's observed power. Because they are anchored to an observed effect from a small study, they should not be interpreted as a definitive design recommendation.

General statistical reasoning: sample-size planning depends on assumptions about the effect to detect, outcome frequency, significance level, power, allocation, and analysis method. If any assumptions differ from those used in an actual future study, the planning figures may not apply. The registry record does not report the original trial's sample-size justification or design assumptions. The planning illustration therefore does not establish what sample size was intended for this trial or why enrollment was set at 50.

No over-dispersion issue is central to the primary endpoint because it is reported as a binary participant outcome, rather than a count of repeated events or a continuous measure. General statistical reasoning: over-dispersion matters when observed variability exceeds what a model assumes, potentially making standard errors too small if not addressed. Whether any such issue was considered for other analyses is not reported in the registry record. Nor does the record describe an interim analysis, stopping rule, missing-data method, or prespecified adjustment for multiple outcomes.

11. Confidence Intervals and Precision

The primary mortality estimate is imprecise. There were 0 recorded events among 20 participants in the pelvic-binder group and 1 among 23 in the no-binder group. The confidence interval for the risk difference crosses zero, so the posted data are compatible with no risk difference as well as with differences in either direction. The interval is the main guide to the range of effects reasonably compatible with these data under the method used; its exact construction method is not reported in the registry record.

The small number of events is central to this imprecision. A point estimate based on one event should not be mistaken for a precise estimate of the underlying mortality difference. The p-value of 0.345 is consistent with substantial uncertainty, but the p-value alone does not express the possible size or direction of the effect. The estimate, interval, and observed counts need to be read together.

For context, overall enrollment is listed as 50, while the primary outcome denominators are 20 and 23. The registry record does not explain the difference, report participant flow, or state how missing data were handled. This limits assessment of how completely the enrolled population is represented by the posted outcome comparison. It is not possible from the record to determine whether the difference reflects eligibility, outcome availability, analysis exclusions, or another reason.

Precision is also limited by the information available about the analysis. The registry does not report the statistical model, interval method, or a detailed analysis plan. The confidence interval should therefore be interpreted as reported, without assuming a particular adjustment or modeling choice beyond the stated risk-difference comparison.

12. Multiplicity, Missing Data and Analysis Populations

The registry record does not report a plan for handling multiplicity across the primary and secondary outcomes. It lists a primary mortality outcome and multiple secondary outcomes, and a numeric comparison is posted for blood transfusions. When investigators examine several outcomes, some results may appear notable by chance even when there is no underlying difference. General statistical reasoning: prespecifying a hierarchy or adjustment approach can help define how evidence across multiple tests should be interpreted. Whether any such approach was used in this trial is not reported in the registry record.

The posted primary comparison is unadjusted, and the registry lists no reported analyses. It does not describe whether additional models, subgroup analyses, or sensitivity analyses were performed. The statistical analysis plan, including the intended analysis population and any covariate adjustments, is not reported in the registry record. It is therefore not possible to evaluate whether the posted comparison reflects all planned analyses or how analysis choices were made.

Missing-data handling is also not reported. Overall enrollment is listed as 50, while the primary outcome has group denominators of 20 and 23. The registry does not provide a participant-flow account or explain this difference. It does not identify the number of participants with unavailable outcomes, state how such outcomes were handled, or indicate whether the analysis followed an intention-to-treat principle. No conclusion about the cause or consequences of the differing denominators should be inferred without that information.

The registry record does not report interim analyses, stopping rules, or monitoring procedures. It also does not describe the procedures used to ascertain the 30-day outcome or the handling of participants whose status could not be confirmed. These omissions do not show that such procedures were absent; they mean that they cannot be evaluated from the registry record. Taken together, missing analysis details limit assessment of completeness, robustness, and the role of multiplicity in interpreting the posted results.

13. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry's adverse-event figures list 0 serious adverse events among 22 participants at risk in the pelvic-binder group and 0 among 28 participants at risk in the no-binder group. The same group-specific denominators and counts are reported for other adverse events: 0 in each group. The adverse-event denominators differ from the denominators used for the primary mortality outcome. The registry record does not explain these differences or provide further detail about adverse-event collection.

The adverse-event record lists deaths of 0 in the pelvic-binder group and 2 in the no-binder group. These safety figures should be kept distinct from the primary endpoint counts, which report 0 and 1 deaths within 30 days among their respective outcome denominators. The registry does not explain the difference between the death figures across these records, including whether the safety and primary outcome records use different populations or timeframes. The figures should not be combined or treated as interchangeable.

Zero reported events do not prove that no events occurred outside the recorded safety population or that a device is free of risk. The record's serious adverse-event terms are not listed. Without additional definitions, ascertainment details, and explanation of the differing denominators, the safety counts are descriptive and do not establish a comparative safety conclusion.

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

The posted primary data show 0 deaths in the pelvic-binder group and 1 in the no-binder group for the 30-day mortality outcome. The risk-difference estimate is oriented toward no binder relative to binder, its confidence interval crosses zero, and its unadjusted p-value is 0.345. This is an uncertain comparison based on very few events. It does not establish a clear mortality difference, but it also does not establish equivalence or rule out effects in either direction.

The randomized design is useful for comparing groups, but the posted information does not answer every question needed to assess the result. The registry record does not explain why the primary outcome denominators differ from total enrollment, report the analysis population, or describe missing-data handling. It also does not report the analysis plan or details of the statistical test. These gaps limit independent assessment of how the analysis was conducted and how fully the outcome data represent enrolled participants.

The result applies to the trial's stated population, intervention, comparator, and 30-day mortality endpoint. It does not, on its own, establish what happens for the other outcome domains listed in the registry, for which numeric findings are not reported in the registry record except for blood transfusions. Nor can the posted comparison answer questions about treatment implementation, effects in specific subgroups, or outcomes beyond the stated timeframe.

Statistical uncertainty is not the same as evidence that two approaches are identical. A confidence interval spanning zero leaves room for a range of possible differences. Conversely, the direction of a point estimate is not sufficient evidence that the difference is real. The most defensible reading is limited: the posted data contain very few primary events and do not precisely distinguish between the groups for 30-day mortality.

15. Why This Trial Matters Statistically

This trial illustrates a central challenge in clinical research: randomized allocation can support a fair comparison, but a comparison with very few outcome events may remain highly uncertain. The primary mortality counts are 0 and 1. Those observations establish the direction of the posted estimate, but they provide limited information about the size of any underlying difference. Statistical significance, effect size, and precision are related but different ideas, and none should be inferred from the event counts alone.

The registry also illustrates why denominators and analysis populations matter. Enrollment is listed as 50, whereas the primary outcome denominators are 20 and 23. The record does not explain the distinction. Without participant flow and missing-data information, readers cannot fully assess how the enrolled participants relate to the primary comparison. This is a reporting limitation, not proof of a particular form of missingness or exclusion.

Another statistical lesson is that multiple outcomes do not provide interchangeable evidence. Mortality, transfusion, pain, skin complications, and hospital length of stay represent different dimensions of outcome. The registry lists these domains but posts numeric results only for the mortality endpoint and blood transfusions. Any secondary interpretation must account for multiplicity and the absence of a reported analysis plan.

Finally, the sample-size planning illustration should be distinguished from the trial's own design rationale and from observed power. It is a planning exercise based on the observed secondary effect and stated assumptions; it does not explain why this trial enrolled 50 participants. The registry record does not report the original sample-size justification. Keeping these distinctions clear helps prevent an imprecise result from being overread as either proof of no difference or proof of a difference.

16. 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 number of primary mortality events is very small: the posted counts are 0 and 1. This limits the precision of the comparison and makes the result sensitive to individual events. The confidence interval crosses zero, and the unadjusted p-value does not establish a clear difference. These features constrain interpretation regardless of the randomized design.

The primary outcome denominators, 20 and 23, do not account for the full enrollment of 50 as listed in the registry. The record does not explain the difference, report participant flow, or describe how missing outcome information was handled. The analysis population and adherence to an intention-to-treat approach are not reported in the registry record, so the effect of these issues cannot be assessed.

Important design and analysis details are also not reported, including randomization procedures, allocation concealment, the statistical analysis plan, the method used for the confidence interval and p-value, and any covariate adjustment. The record does not report interim analyses or stopping rules. These omissions limit evaluation of the methods and whether the posted analysis followed a prespecified plan.

The registry lists secondary outcome domains for pain, skin complications, hospital length of stay, and blood transfusions, but numeric findings are posted only for blood transfusions. The record does not report a multiplicity strategy, making it difficult to judge the weight of an individual secondary comparison. Safety denominators also differ from the primary outcome denominators, and the record does not explain why. These are trial-specific reporting limits; they do not by themselves establish that the underlying procedures were inadequate.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Pre-hospital Advanced Therapies for Control of Hemorrhage - Pelvis — NCT02855060.
• Registry record last updated 2022-04-21; status last verified 2021-07.
• Results first posted 2021-08-02.
• 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.

20. Record Summary

NCT02855060, titled Pre-hospital Advanced Therapies for Control of Hemorrhage - Pelvis, was a randomized, open-label, parallel-group study sponsored by Wake Forest University Health Sciences. The registry lists enrollment of 50, status completed, a start of 2016-07, and primary completion in 2018-06. The phase is listed as NA.

The trial compared a commercially available pelvic binder with no binder, described as standard of care. The primary endpoint was mortality within 30 days of presentation. Posted counts were 0 among 20 participants in the binder group and 1 among 23 in the no-binder group. The unadjusted p-value was 0.345, and the confidence interval for the risk difference crossed zero.

The registry lists secondary outcomes related to pain, skin complications, hospital stay, and blood transfusions. Numeric secondary results are posted for blood transfusions within 48 hours. The registry record does not report the original sample-size justification, analysis plan, analysis population, or explanation for the difference between enrollment and primary outcome denominators. The sparse primary events and incomplete analysis detail call for cautious interpretation.