Optimal Fluid Resuscitation for Trauma Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Optimal Fluid Resuscitation for Trauma Patients (NCT00527098), a registered phase not stated study. The primary outcome is Mortality.

2. Clinical Question

This distinction matters when interpreting the record. A stated research objective does not establish that the corresponding measure was reported as an outcome, and a listed endpoint does not itself establish what the results were. The registry describes the groups but does not state that allocation was randomized; it explicitly notes that the groups are not a like-for-like control comparison. Consequently, the record does not support treating any difference between the groups as an unambiguous effect of Hextend. It also does not report enough information to judge whether the per-protocol population represents all enrolled patients.

3. Trial Design

The registry identifies the study as “Optimal Fluid Resuscitation for Trauma Patients” and lists the condition as trauma. The sponsor is the University of Miami. The record gives a start date of 2007-10, a primary completion date of 2010-07, and a status of completed. Enrollment is reported as 119. These details describe the registry entry; they do not by themselves establish how many participants contributed to the primary analysis.

Two groups are listed: Hextend Plus Standard of Care and Standard of Care. The registry does not state the allocation method. It specifically cautions that the comparison is not randomized, with allocation not stated, and that the arms are not a like-for-like control comparison. That warning limits causal interpretation: differences between the groups could reflect differences other than the fluids under study, and the record does not supply enough information to assess or adjust for such differences.

The primary outcome is mortality, recorded as a number of participants, with a timeframe from hospital arrival up to an average of 3.5 weeks. Its analysis population is described as per protocol. The registry lists the group sizes at risk for serious adverse events as 36 for Hextend Plus Standard of Care and 83 for Standard of Care. Those safety denominators should not be assumed to be the primary analysis denominators. The relationship between them, enrollment, and the per-protocol population is not reported in the registry record.

Further design details—including eligibility criteria, treatment assignment procedures, masking, fluid administration protocols, and the planned statistical analysis—are not reported in the registry record. The registry lists no statistical analyses. Therefore, the design description is limited to the stated groups, dates, enrollment, outcome, and explicit warning about the comparability of the arms.

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

Analysis population for the primary outcome, as defined in the registry: Analysis was 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.

6. Primary Endpoint

The registry lists the primary outcome as Mortality, measured over From hospital arrival up to an average of 3.5 weeks.

The listed primary endpoint is mortality, measured as the number of participants who died. The timeframe is from hospital arrival up to an average of 3.5 weeks. The registry describes the analysis as per protocol, meaning the listed population is defined by adherence to the study protocol rather than simply by enrollment; the exact criteria used to define that population are not reported in the registry record.

Mortality is a binary outcome at the participant level: each participant either experiences the event during the stated observation period or does not. In general, this kind of endpoint can be summarized with event counts and the number of participants assessed. Comparing such outcomes requires clear group definitions, complete outcome ascertainment, and an analysis appropriate to the study design. Those general principles do not fill in missing trial results or methods.

The registry gives no mortality counts, group-specific mortality estimates, confidence intervals, or test results. It therefore does not show how many participants died or how precisely any comparison was estimated. The average-length wording in the timeframe also does not specify an exact follow-up duration for each participant. Details about follow-up, censoring, and outcome ascertainment are not reported in the registry record.

The study summary focuses on whether overall fluid requirements during the first 24 hours after admission would be reduced. That is not the primary endpoint listed in the registry. No fluid-requirement outcome or result is reported in the registry record, so the stated objective cannot be used as evidence of a measured effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry lists mortality as a binary endpoint measured by the number of participants. For a binary outcome, each participant is classified according to whether the event occurred during the relevant follow-up. In general, a group-level analysis reports the event count alongside the number of participants evaluated. An effect estimate then describes a contrast between groups, while a confidence interval describes the range of values compatible with the data and the analysis assumptions. No such mortality counts, estimates, or intervals are reported in the registry record, so none can be interpreted for this study.

What does the per-protocol description mean?

The registry says that the primary analysis was per protocol. In general, a per-protocol analysis focuses on participants who met specified adherence or eligibility conditions during the study. The precise rules matter: different rules can include or exclude different participants. The criteria, exclusions, and resulting analysis denominators are not reported in the registry record. It is therefore not possible to determine how the per-protocol population was constructed or how it relates to the reported enrollment.

Per-protocol analyses can also be vulnerable to selection effects. For example, adherence and continued participation may be related to health status or other factors that also affect outcomes. This is a general statistical consideration, not a finding about this study. The registry does not report information that would establish whether such effects arose or how they were handled.

Why does allocation matter?

Random allocation, when used and implemented appropriately, is a method intended to balance both known and unknown participant characteristics across groups on average. The registry does not state that allocation was randomized. It explicitly says allocation was not stated and that the arms are not a like-for-like control comparison. These cautions mean that a simple difference between group outcomes, even if one were reported, would not automatically identify the effect of Hextend. The registry does not describe an adjustment model or another strategy for controlling group differences.

In general, an analysis should match the design and outcome. A binary endpoint may be analyzed using methods that compare event probabilities or counts, with uncertainty quantified under stated assumptions. If follow-up differs across participants or includes censoring, methods that account for time to event may be relevant. The registry’s mortality timeframe does not establish that such a method was used, and the record lists no analyses. The statistical method for mortality is not reported in the registry record.

How should confidence intervals and significance tests be read?

Generally, a confidence interval conveys uncertainty around an estimate under the chosen statistical model. A narrow interval indicates greater precision than a wide interval, while an interval spanning values that imply different conclusions may leave the comparison uncertain. A significance test addresses compatibility with a specified null hypothesis under its assumptions; it does not, by itself, describe the size or clinical importance of an effect. These are general explanations. No mortality confidence interval, p-value, or effect estimate is reported in the registry record, so these concepts cannot be applied to a numerical mortality result for this trial.

The record does not state a statistical analysis plan, a model, covariates, or an approach to uncertainty. It also does not report whether any interim analyses were planned or conducted. These details should not be inferred from the endpoint label or study status.

What do the planning assumptions describe?

The planning assumptions describe illustrations based on a stated fraction of the observed effect, a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. They are planning illustrations, not observed power. In general, a planning calculation estimates the number of participants needed under selected assumptions about the effect and analysis; it does not measure the probability that a completed study has detected a true effect. The record does not report the numerical planning outputs or a sample-size justification from the trial’s own design.

The assumptions refer to a fraction of an observed effect, but the registry record does not report the mortality effect needed to interpret such an illustration. The stated equal-allocation assumption is a planning assumption and should not be mistaken for a description of actual enrollment or allocation. Nor does it resolve the registry’s warning that the arms are not a like-for-like control comparison.

Finally, a statistical analysis depends on well-defined outcomes, denominators, and handling of missing information. The registry lists one outcome measure and no analyses, but does not describe missing-data procedures or outcome ascertainment. General statistical principles can clarify why these details matter; they cannot replace the unreported methods or results.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Observational")
n      <- c(119)
events <- c(0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Observational  119  0  0.0  0.0  3.1  0.0  3.1  0.0  3.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure: mortality. It reports no statistical analyses. A single listed outcome does not establish that no other outcomes were collected or considered, and the study summary also describes a question about fluid requirements. However, fluid-requirement results are not reported in the registry record. The record does not say whether there were multiple hypotheses, prespecified secondary outcomes, subgroup analyses, or any adjustment for multiple testing. These details are not reported in the registry record.

In general, multiplicity arises when investigators make several statistical comparisons or examine multiple outcomes. Repeated testing can increase the chance of finding an apparently notable result by chance, so a statistical plan may specify how comparisons are prioritized or adjusted. This is a general methodological point. With no analyses or results listed, there is no basis for assessing how multiplicity was handled in this study.

Missing-data handling is also not described. The registry does not report the number of participants with missing mortality status, reasons for missing outcome information, or methods used to address missingness. A missing outcome must not be treated as an event-free outcome without a stated justification. The mortality counts themselves are not reported, so the extent of missingness cannot be evaluated.

The primary outcome population is described as per protocol, but the protocol criteria and analysis denominator are not reported. The registry also does not explain the relationship between the enrollment figure, the safety denominators, and the primary analysis population. These gaps limit assessment of both attrition and analysis-population selection. The registry record does not report interim analyses or a statistical analysis plan.

12. Safety Results

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

Other (non-serious) adverse events

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

The serious adverse event entries list zero participants with a serious event in the Hextend Plus Standard of Care group and zero in the Standard of Care group. The corresponding numbers at risk are 36 and 83. The record lists no serious adverse event terms. These figures describe the entries for serious adverse events; they are not the mortality outcome results.

A zero count means that no serious adverse event was recorded in the relevant entry for the stated group denominator. It does not establish that participants experienced no adverse events of any kind, nor does it rule out events that were not captured or reported. The registry does not provide event narratives, event-specific counts, follow-up completeness, or additional safety analyses. It also does not explain why the safety denominators differ from the enrollment figure, so those counts should not be treated as the primary endpoint population.

In general, safety counts are interpreted in light of how events were defined, collected, and monitored, as well as the number of people observed and the duration of observation. The registry record does not report those details beyond the serious-event counts and numbers at risk. Accordingly, the safety entries are limited descriptive information, not a comprehensive assessment of comparative safety.

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

The record establishes that a completed study concerned fluid resuscitation in trauma patients and listed Hextend Plus Standard of Care and Standard of Care as its groups. It reports mortality as the primary endpoint, with follow-up from hospital arrival up to an average of 3.5 weeks. It also records zero serious adverse events in each group among the stated at-risk denominators. These are the reported details; they do not provide a complete outcome comparison.

The registry does not report mortality counts or a statistical analysis of mortality. It therefore cannot show from the posted results whether mortality differed between groups, how large any difference was, or how precisely it was estimated. The study summary’s stated aim concerning fluid requirements during the first 24 hours likewise does not establish a result: fluid-requirement findings are not reported in the registry record.

The registry’s explicit warning about allocation and comparability is important. Since allocation is not stated and the arms are not described as a like-for-like control comparison, even a reported difference would need cautious interpretation. Without information on group comparability or an analysis addressing it, a difference could not be attributed confidently to the fluid strategy alone.

The record also does not report enough detail to determine how the per-protocol population was defined, how missing outcomes were handled, or what statistical methods were used. Enrollment should not be substituted for an unreported analysis denominator. Similarly, the serious adverse event entries do not answer the mortality question or establish that no other harms occurred.

In general, a trial result is most informative when it includes outcome counts, effect estimates, uncertainty intervals, and a clear account of the design and analysis. Those elements are not reported for the primary outcome in this registry record. The appropriate conclusion is limited: the study’s intended question and listed endpoint can be described, but the record does not establish the result of either the mortality comparison or the fluid-requirement question.

14. Why This Trial Matters Statistically

This trial record illustrates why a stated study objective, a listed endpoint, and a reported result must be distinguished. The summary describes a question about reducing fluid requirements during the first 24 hours after admission. The listed primary outcome is mortality over a timeframe from hospital arrival up to an average of 3.5 weeks. Neither description can stand in for the other, and the registry does not report fluid-requirement results or mortality results.

It also illustrates the importance of study design when interpreting group comparisons. The registry expressly says that allocation was not stated and the arms are not a like-for-like control comparison. In general, statistical comparisons rely on design and analysis assumptions; when groups may differ in ways unrelated to treatment, an observed contrast can be difficult to interpret causally. This issue remains even when outcome data are available, and it is especially consequential when the record does not provide those results.

The per-protocol population description raises a further reporting question. Readers need to know who was included in the analysis and why. Without the per-protocol criteria or analysis denominator, the reported enrollment cannot be assumed to represent the participants contributing to the primary endpoint.

Finally, the record shows why safety counts need context. Zero serious adverse events are reported in the stated group denominators, but the registry does not describe event ascertainment or provide a broader safety analysis. Clear denominators and complete methods help readers understand what counts can and cannot establish. Here, the limited reporting allows a description of the record but not a firm statistical conclusion about comparative outcomes.

15. 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 most important limitation of the registry record is that it does not report the primary mortality results. There are no group-specific death counts, effect estimates, confidence intervals, or test results. The stated primary endpoint therefore cannot be used to evaluate the direction, magnitude, or precision of a mortality comparison.

The registry also cautions that the comparison is not randomized, with allocation not stated, and that the arms are not a like-for-like control comparison. This prevents an uncomplicated causal interpretation of any group contrast. The record does not give baseline characteristics or describe an adjustment strategy that could help evaluate or address differences between the groups.

The analysis population is described as per protocol, but the criteria and number analyzed are not reported. The registry’s enrollment figure and safety denominators do not resolve this gap, and the record does not explain their relationship. Missing outcome information and its handling are also not reported.

There is a mismatch between the study summary’s fluid-requirement objective and the single listed endpoint, mortality. No fluid-requirement measure or result is reported in the registry record. Other relevant methods—including eligibility criteria, treatment protocols, outcome ascertainment, and the statistical analysis plan—are not reported either. The record lists no analyses and does not state whether interim analyses occurred.

The serious adverse event entries are limited to zero reported events in each group and the stated numbers at risk. Event definitions, collection procedures, and a fuller safety assessment are not reported. These limitations are specific to the information in the registry record and mean that its descriptive details should not be mistaken for a complete evaluation of effectiveness or safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Optimal Fluid Resuscitation for Trauma Patients — NCT00527098.
• Registry record last updated 2013-02-22; status last verified 2013-02.
• Results first posted 2011-05-04.
• 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.

19. Record Summary

The registry record describes a completed study of fluid resuscitation in patients with trauma, sponsored by the University of Miami. It reports enrollment of 119, a start date of 2007-10, and a primary completion date of 2010-07. The listed groups are Hextend Plus Standard of Care and Standard of Care.

The summary describes a question about fluid requirements during the first 24 hours after admission. The primary endpoint listed is mortality, measured as participants from hospital arrival up to an average of 3.5 weeks, with analysis described as per protocol. Mortality results and fluid-requirement results are not reported in the registry record.

The record states that allocation was not stated, that the comparison is not randomized, and that the arms are not a like-for-like control comparison. It lists zero serious adverse events in each group, with 36 and 83 participants at risk, respectively. No statistical analyses are listed. The record does not report the statistical plan, missing-data handling, or details defining the per-protocol population.