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 Causes and Circumstances of Horse Related Injuries and Impact on Quality of Life (NCT00935428), a registered phase not stated study. The primary outcome is Injury Severity Score (ISS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00935428 |
| Phase | Phase not stated |
| Condition | Injury |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 231 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Oregon Health and Science University |
| Results posted | Yes |
2. Clinical Question
Population
The primary outcome population is described as all patients evaluated at OHSU Hospital with horse-related injuries. The registry lists enrollment of 231. It does not report how many people contributed data to the primary outcome or whether every enrolled participant was included in that analysis.
Intervention
No treatment intervention is described. The study’s stated purpose was to examine causes and circumstances of horse-related injuries and their impact on quality of life. The brief summary says investigators intended to interview injured equestrians to examine patterns in decision-making and behavior and to inform safety recommendations.
Comparator
No comparator group is specified. The registry record states that this was not a randomized comparison and that allocation was not stated. Any groups represented in the record therefore should not be treated as randomized, like-for-like control groups.
Primary question
The primary outcome is the Injury Severity Score (ISS), reported as a mean with a full range over the timeframe 2008-2011. The record identifies the population and explains the score, but does not report the mean or range. The clinical question is therefore descriptive: what injury severity was recorded for the stated population, and what do the study’s broader aims say about circumstances and quality of life? Numerical answers to those questions are not reported in the registry record.
3. Trial Design
The registry record describes a completed study sponsored by Oregon Health and Science University. Its title and summary concern causes and circumstances of horse-related injuries and their impact on quality of life. The stated plan was to learn from injured equestrians’ experiences, examine possible patterns in decision-making and behavior, and develop safety and prevention recommendations. The summary also describes a long-term goal of developing a horse-related injury prevention program. These are stated aims, not reported findings.
The record lists enrollment of 231 and identifies Injury as the condition. It gives a study start of 2009-06 and primary completion of 2010-06. The primary outcome’s stated timeframe is 2008-2011. Those dates describe different registry fields; the record does not explain their relationship or how outcome observations were collected across that timeframe.
The study is categorized as “other.” It is not described as a randomized comparison, and allocation is not stated. No intervention or comparator is identified, so the listed enrollment should not be interpreted as a randomized treatment assignment or as evidence of a controlled treatment effect. The record does not report a detailed design description, recruitment procedure, eligibility criteria, interview instrument, follow-up schedule, or analysis plan. Those details are not reported in the registry record.
Six outcome measures are listed, but the record does not provide numerical findings for the primary ISS outcome. The registry also lists zero analyses. This means the posted record does not include a reported analysis from which to assess an estimated effect, uncertainty, or statistical significance. A completed status does not itself establish that any particular analysis was conducted or that the stated aims were achieved.
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 | Patients Injured |
|---|---|
| STARTED | 231 |
| COMPLETED | 231 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: All patients evaluated at OHSU Hospital with horse-related injuries
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: Patients evaluated at OHSU Hospital with horse related injuries
| Characteristic | Unit | Patients Injured |
|---|---|---|
| Participants analysed | 231 | |
| Age, Continuous | years | 38 (2 to 75) |
| Sex: Female, Male: Female | Participants | 151 |
| Sex: Female, Male: Male | Participants | 80 |
| Region of Enrollment: United States | participants | 231 |
6. Primary Endpoint
The registry lists the primary outcome as Injury Severity Score (ISS), measured over 2008-2011.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | units on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the Injury Severity Score (ISS), described as a mean with a full range and expressed in units on a scale. The registry identifies the outcome population as all patients evaluated at OHSU Hospital with horse-related injuries and gives the timeframe as 2008-2011.
ISS is based on the Abbreviated Injury Scale (AIS). The body is divided into 6 regions, each scored from 1 for minor severity/better to 5 for most severity/worse. The total ISS is calculated by squaring the scores for the 3 most severely injured body regions and summing those squared values. The stated possible total score ranges from 3 to 75. Because the component scores are squared, higher scores in the most severely injured regions contribute more strongly to the total than they would in a simple sum.
In general, a mean gives a compact description of the average score, while a full range describes the lowest and highest observed values. Reporting both can provide context about the center and spread of the observed scores, although the range alone does not show how observations are distributed between its endpoints. The registry record does not report the observed mean or full range, so the endpoint’s numerical result and its precision cannot be assessed from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies ISS as the primary outcome and defines the population and timeframe, but it does not report the observed mean, the full range, or an analysis of the outcome. Consequently, the posted results do not establish the observed severity profile for the stated population. There is no numerical estimate to interpret, and no confidence interval or other measure of uncertainty for the primary endpoint is reported in the registry record.
The record’s summary explains why the investigators considered horse-related injuries important and describes goals related to decision-making, behavior, quality of life, and prevention. These statements provide context for the research question; they are not evidence that particular injury causes were identified, that quality of life changed by a particular amount, or that any safety recommendation was tested. The record does not report findings for those aims.
The study is not described as a randomized comparison, allocation is not stated, and no comparator is specified. The reported enrollment therefore cannot be read as a treatment-versus-control comparison. Without a defined comparison and an analysis, no causal effect or between-group difference can be interpreted. The record also gives no basis for attributing an observed injury outcome to a particular behavior, decision, or safety measure.
In general, an estimate should be considered together with its uncertainty and with the design that produced it. A confidence interval, when reported, describes a range of values compatible with the data under the analysis assumptions; it does not by itself remove limitations from selection, measurement, or study design. Here, the registry record does not report a confidence interval or a numerical estimate for ISS, so the precision of the primary outcome is unknown from the posted results.
The record reports zero serious adverse events, zero other adverse events, and zero deaths in the listed participant group. These are registry entries, not a detailed account of how safety information was collected, the observation window, or the completeness of reporting. They should be read as the recorded counts rather than as proof that no adverse experiences occurred outside the recorded categories or period. Overall, the registry describes a research aim and an endpoint, but does not supply enough outcome data to evaluate the primary result or draw conclusions about the stated prevention goals.
9. Statistical Methods Explained
The registry record names a descriptive injury-severity measure, the Injury Severity Score (ISS), and specifies that it is to be summarized by a mean and full range. It does not provide a detailed statistical methods section. The analysis plan, handling of missing observations, use of adjustments, and any inferential procedures are not reported in the registry record. The distinction matters: an endpoint definition explains what was intended to be measured, while a statistical analysis description explains how the observations were turned into a result.
What does a mean describe?
In general, a mean is an average across the observations included in an analysis. It gives a single summary of the center of the observed values, but it does not show whether most observations cluster near that value or whether the average is influenced by unusually high or low observations. For ISS, interpretation also depends on the score’s construction: the most severely injured regions are scored, squared, and combined. The registry record does not report the observed mean, the number of observations contributing to it, or any accompanying uncertainty estimate.
What does a full range add?
In general, a full range describes the smallest and largest observed values. It can indicate the span of recorded scores but does not describe how often values occurred within that span. A range may be sensitive to extreme observations and does not substitute for a distributional summary or an uncertainty interval. The record specifies a full range as the dispersion measure for ISS, but the observed endpoints of that range are not reported in the registry record.
How is ISS constructed?
The registry describes the AIS-based score as dividing the body into 6 regions, assigning each region a score from 1 to 5, and squaring the scores for the 3 most severely injured regions before summing them. The stated total score can range from 3 to 75. In general, this construction gives greater weight to higher scores among the selected regions than a simple addition would. It is a severity summary, not a direct measure of quality of life, injury circumstances, or the cause of an injury. The record does not report the AIS observations or details of how scoring was conducted in practice.
What can be inferred without a comparison?
In general, a comparison estimates how outcomes differ between groups defined by a study design or analysis. Interpretation depends on how those groups were formed and whether relevant differences were addressed. Here, the registry states that the study was not a randomized comparison, that allocation was not stated, and that the groups are not a like-for-like control comparison. It does not identify a primary comparator or report a group-based ISS analysis. A treatment effect or causal contrast therefore cannot be recovered from the registry information.
How should uncertainty and significance be assessed?
In general, an uncertainty interval communicates the range of estimates compatible with the observed data under specified assumptions. A p-value, when used, relates the data to a stated statistical hypothesis and model; it does not measure the size or importance of an effect. Neither a p-value nor a confidence interval for ISS is reported in the registry record. No statistical hypothesis test for the primary outcome is reported, so statistical significance cannot be assessed from the posted results.
The record includes planning assumptions for sample-size illustrations: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. It also distinguishes planning outputs for time-to-event outcomes from those for other outcomes. These assumptions describe planning illustrations, not the study’s own design or an observed-power calculation. No numerical planning result or observed effect is reported in the registry record, so no sample-size conclusion can be drawn from those assumptions alone.
More broadly, the registry lists zero analyses. That listing does not provide an analysis specification or numerical results. The statistical plan, any interim analyses, model choices, covariate adjustments, distributional assumptions, and sensitivity analyses are not reported in the registry record. General statistical concepts can clarify what the stated endpoint and summary measures mean, but they cannot replace the missing analysis details or yield an estimate that the record does not report.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists six outcome measures and identifies ISS as the primary outcome. It does not report how the other outcomes were prioritized, whether multiple outcomes or comparisons were tested, or whether any adjustment for multiple testing was planned. Multiplicity is a general concern when many hypotheses are examined: the chance of finding an apparently unusual result can depend on how many analyses are conducted and how they are selected. No multiplicity strategy is reported in the registry record, so the effect of multiple testing on any findings cannot be assessed.
The record lists zero analyses and does not provide numerical primary outcome results. It does not report how missing ISS observations or missing quality-of-life information were handled, whether participants were excluded from particular analyses, or how incomplete interviews or outcome assessments were treated. Those missing-data procedures are not reported in the registry record. In general, missingness can affect both the number of observations analyzed and the interpretation of a result, especially if the absence of a measurement is related to participant characteristics or outcome values.
The registry identifies the primary outcome population as all patients evaluated at OHSU Hospital with horse-related injuries, while enrollment is listed as 231. It does not specify an analysis population, a denominator for the primary endpoint, or whether the enrolled participants and outcome population correspond exactly. The record also does not describe eligibility rules, exclusions, or an intention-to-treat population. These details are not reported in the registry record; no analysis population should be inferred from the enrollment figure alone.
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 |
|---|---|---|---|
| Participants | 0 | 231 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Participants | 0 of 231 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Participants | 0 of 231 |
The adverse-event record lists the group as Participants, with 231 at risk for serious adverse events and 0 affected. It also lists 231 at risk for other adverse events and 0 affected, and reports 0 deaths. No serious adverse-event terms are listed. These entries describe what was recorded in the registry fields; they are not a detailed safety analysis.
The record does not report the safety observation period, the criteria used to classify an event as serious, how adverse events were solicited, or whether events were independently reviewed. It also does not explain how the adverse-event reporting population relates to the primary endpoint population. These details are not reported in the registry record.
In general, a zero recorded count means no events were entered in that category for the stated record. It does not, by itself, establish how completely events were captured or whether the observation period was sufficient to identify every relevant event. The counts should therefore be read as registry reporting, not as a guarantee that no adverse experiences occurred.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study concerned horse-related injuries and quality of life, and that the primary outcome was ISS for patients evaluated at OHSU Hospital with horse-related injuries. It describes how ISS is constructed and gives its stated timeframe. It also reports enrollment of 231 and a completed status.
It does not report the observed ISS mean or full range. It does not provide a numerical quality-of-life result, describe the injury circumstances found, or identify which behaviors or decisions were associated with injury. The study’s stated interest in those topics should not be mistaken for evidence that a particular pattern was observed. The numerical results and analyses needed to answer those questions are not reported in the registry record.
The record does not describe a randomized comparison, identify a comparator, or state an allocation procedure. As a result, it does not support a causal interpretation comparing treatments or safety approaches. The record’s prevention goals are aims for future work, not evidence that an injury-prevention program was implemented or evaluated.
In general, a completed study status indicates the registry’s status entry, not that every stated objective has a posted result. A numerical estimate also needs context about who contributed data, how measurements were made, and how uncertainty was assessed. Those details are absent for the primary endpoint. The adverse-event fields record zero events and zero deaths, but the record does not give enough information about ascertainment or follow-up to interpret those entries beyond their recorded categories.
The appropriate reading is therefore limited: the registry describes a study focus, a primary severity measure, a population, and an endpoint timeframe. It does not provide the results needed to characterize injury severity numerically, assess precision, test associations, or determine whether the stated long-term prevention goals were met.
13. Why This Trial Matters Statistically
This study is statistically relevant because it illustrates the difference between a clearly named endpoint and a reported endpoint result. The registry defines ISS, identifies the population to which the primary outcome refers, and specifies a summary as a mean with a full range. Those details help a reader understand what the investigators intended to describe. Without the observed summary values or an analysis population, however, the endpoint cannot be evaluated empirically from the posted record.
The registry also places injury severity alongside broader interests in injury circumstances and quality of life. These are related research questions, but they are not interchangeable measures. A severity score describes an aspect of injury; it does not, by itself, explain the circumstances of injury or the effect on quality of life. Analyses connecting those domains would need reported measurements and methods, which are not reported in the registry record.
The nonrandomized status and absence of a specified comparator are important for statistical interpretation. Descriptive evidence can characterize observations in a defined population, while causal claims require a design and analysis that support comparison. The record does not report such a comparison, so conclusions about the effect of a behavior or intervention cannot be drawn from it.
Finally, the record shows why outcome definitions, study aims, and results should be read separately. The study’s safety-prevention goals may motivate further research, but goals alone do not quantify an association or demonstrate a reduction in injuries. Here, the registry provides useful context about the intended questions and the ISS construction, while leaving the principal numerical findings and analysis methods unreported.
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 main limitation for interpreting this specific registry record is the absence of numerical primary outcome results. Although ISS is named and its scoring approach is described, the observed mean and full range are not reported. The record also does not report a confidence interval, denominator for the primary analysis, or details about the distribution of scores.
The outcome population is described as all patients evaluated at OHSU Hospital with horse-related injuries, but the record does not provide eligibility criteria, recruitment details, or the number contributing data to that endpoint. Enrollment is listed as 231; it should not be assumed that every enrolled participant contributed to every outcome. Analysis-population details are not reported in the registry record.
The primary endpoint timeframe is 2008-2011, while the registry gives a study start of 2009-06 and primary completion of 2010-06. The record does not explain how these time periods relate or how observations from the stated outcome timeframe were assembled. Measurement procedures, ISS scoring personnel, quality checks, and missing-data handling are also not reported in the registry record.
The study is not described as randomized, allocation is not stated, and no comparator is specified. The record therefore does not support a controlled treatment-effect interpretation. It also does not report the interview procedures or results needed to assess the stated aims regarding injury circumstances, behavior, decision-making, or quality of life. These limitations reflect what is available in the registry record and do not establish what may have been done outside it.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Causes and Circumstances of Horse Related Injuries and Impact on Quality of Life — NCT00935428.
- Registry record last updated 2020-01-13; status last verified 2019-12.
- Results first posted 2020-01-13.
- 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
NCT00935428 is a completed study sponsored by Oregon Health and Science University concerning causes and circumstances of horse-related injuries and their impact on quality of life. The registry lists enrollment of 231 and identifies Injury as the condition. The study is categorized as other and is not described as a randomized comparison; allocation is not stated.
The primary outcome is mean ISS with a full range, for all patients evaluated at OHSU Hospital with horse-related injuries, over the timeframe 2008-2011. The record explains the score’s construction but does not report its observed mean or range. It lists six outcome measures and zero analyses. Serious adverse events, other adverse events, and deaths are each recorded as zero in the adverse-event fields.
The record describes aims related to injury circumstances, quality of life, and future safety recommendations. Numerical findings for those aims and the statistical analysis details are not reported in the registry record.