Validation of Falls Decision Rule to Exclude Intracranial Bleeding in Geriatric Fall Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Validation of Falls Decision Rule to Exclude Intracranial Bleeding in Geriatric Fall Patients (NCT06525727), a registered phase not stated study. The primary outcome is Number of Participants With the Clinically Important Intracranial Bleeding.

2. Clinical Question

The rationale in the registry record is that intracranial bleeding after a fall is described as relatively uncommon, while its consequences can be serious. A decision rule is intended to help identify patients for whom imaging may be avoidable without missing clinically important bleeding. That is a question of diagnostic performance and clinical classification, not a comparison of two assigned treatments.

For a validation study, the relevant evidence would ordinarily include how the rule classifies patients and how those classifications compare with the outcome definition. The registry record does not report the rule's threshold, its component criteria, or performance measures such as sensitivity, specificity, or predictive values. Those details, along with primary outcome event counts, are not reported in the registry record. The study's stated question can therefore be described, but its answer cannot be inferred from the record.

3. Trial Design

The registry describes an external validation study of the Falls Decision Rule in geriatric patients presenting to the emergency department after a fall. The listed intervention is the Falls Decision Rule, classified as type OTHER. The eligible group is described as patients aged 65 years and over who had a specified fall within the last 48 hours. The registry lists enrollment as 800.

The record gives a start date of 2024-01-20, a primary completion date of 2024-10-01, and a status of COMPLETED. These record entries describe the study's administrative status and timeline; they do not establish that all planned follow-up or analyses were completed in a particular way. The study describes follow-up for 42 days after the fall to evaluate delayed intracranial hemorrhage.

This is not described as a randomized comparison, and allocation is not stated. No separate control arm is described as a like-for-like comparator. Accordingly, the design should be understood as an evaluation of a decision rule within the specified clinical population, not as evidence from randomized treatment assignment.

The registry identifies one primary outcome and two secondary outcomes concerning neurosurgical intervention and mortality. It also lists 3 outcome measures and 6 analyses. The exact analysis populations, rule application procedures, data collection procedures, and statistical analysis plan are not reported in the registry record. The entry does not state how participants were selected for imaging or how the rule's classifications were compared with the outcome standard. These omissions limit the detail with which the validation design can be reconstructed from the record.

Enrollment is a registry entry, not a reported count of participants with complete outcome data. The number with usable follow-up, the number assessed by the rule, and the number included in each analysis are not reported in the registry record. Those quantities matter when judging how much information supports any validation estimate.

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 Number of Participants With the Clinically Important Intracranial Bleeding, measured over From baseline to 42 days (Patients will be followed up for 42 days after the fall and evaluated for delayed intracranial haemorrhage)..

The primary endpoint is the number of participants with clinically important intracranial bleeding identified within 42 days following the initial emergency department presentation. The registry defines the outcome as bleeding within the cranial vault, including subdural, intracerebral, intraventricular, subarachnoid, epidural hemorrhage, and cerebral contusion, when medical or surgical intervention is needed.

The definition of medical intervention includes temporary or permanent cessation of anticoagulant or antiplatelet medication, administration of an antifibrinolytic agent, reversal of anticoagulation, or hospitalization for neurological monitoring. The registry states that these criteria align with those used in the original study. Follow-up through 42 days is intended to include delayed intracranial hemorrhage as well as findings from the initial presentation.

This endpoint is clinically focused: it counts participants meeting a specified definition rather than measuring the amount of bleeding or the severity of symptoms on a scale. In a decision-rule validation, a clearly defined outcome is needed to judge whether rule-based classification identifies the condition the rule is meant to exclude. The endpoint definition alone does not establish how accurately the rule performed. The number of participants meeting the primary endpoint, and the diagnostic-accuracy estimates, are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does external validation mean?

In general, external validation evaluates a previously developed prediction or decision rule in a population distinct from the population in which the rule was developed. The goal is to learn whether its classifications remain informative when applied to new patients and clinical settings. This trial is described as an external validation of the Falls Decision Rule among older adults presenting after a fall. The registry record does not describe the original rule's full criteria, the validation threshold, or how the rule was applied in practice.

Validation depends on a comparison between the rule's classifications and a defined outcome. Here, the primary outcome definition concerns clinically important bleeding identified within 42 days, with specified forms of intracranial hemorrhage and intervention criteria. The record does not describe a complete classification matrix or report estimates that compare rule results with outcome status. Therefore, the stated validation objective cannot be translated into a numerical assessment of performance from this record.

What do diagnostic-accuracy measures describe?

In general, sensitivity describes how often a rule identifies people who have the condition of interest, while specificity describes how often it classifies people without the condition as not having it. Predictive values describe the probability of the condition given a positive or negative classification. These measures answer different questions and depend on the study population and outcome definition. For a rule intended to exclude a condition, the rate of missed cases and uncertainty around that rate are especially relevant to interpretation. None of these measures is reported in the registry record.

A count of participants with the endpoint is not, by itself, a diagnostic-accuracy analysis. To assess a rule, readers need to know how many participants with and without the outcome received each classification, as well as how missing or indeterminate classifications were handled. Those details are not reported in the registry record. The endpoint count itself is also not reported.

Why does the outcome definition matter?

In general, an outcome definition determines which events contribute to an analysis. A broad definition may include more types of events, while an intervention-based criterion can restrict the endpoint to events judged clinically consequential. Here, the registry's definition includes multiple types of intracranial bleeding and specifies forms of medical or surgical intervention. This makes the endpoint more specific than simply counting any radiographic bleeding, but interpretation still depends on consistent ascertainment and application of the stated criteria. Procedures for adjudication or independent review are not reported in the registry record.

The follow-up period is intended to capture delayed hemorrhage as well as events identified at the initial presentation. In general, a fixed follow-up window helps define which events belong to an endpoint, but it also requires adequate follow-up and consistent outcome collection. The registry record does not report completeness of follow-up or how participants without observed outcomes were treated in analysis.

What does a confidence interval add?

In general, a point estimate gives a single estimated value, whereas a confidence interval describes uncertainty around that estimate under the statistical model and sampling assumptions. A narrow interval indicates greater precision than a wide interval, though precision does not by itself establish clinical importance or absence of bias. For a diagnostic validation, intervals around sensitivity or the rate of missed cases would help readers judge how precisely performance is estimated. No such estimates or intervals are reported in the registry record.

The record lists 6 analyses, but does not describe their methods, the specific estimates, or whether any intervals were calculated. It also does not state whether analyses were adjusted for other variables. Those details are not reported in the registry record, so the analysis cannot be reconstructed or its assumptions checked from the posted information.

How should planning illustrations be read?

In general, sample-size calculations based on an observed effect are planning illustrations, not evidence that a study had a particular probability of detecting an effect after it was completed. The registry description of the planning illustration specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of the observed effect. For time-to-event outcomes, the stated convention is a total number of events; for other outcomes, it is participants per arm.

Those assumptions do not make this validation a randomized, two-arm study. The registry does not describe a like-for-like control comparison, and allocation is not stated. The numerical planning outputs and the effect fractions are not reported in the registry record. Such calculations cannot replace observed validation results, and they should not be described as observed power.

More generally, over-dispersion occurs when observed variability in count data exceeds what a simple model assumes. Accounting for it can affect standard errors and interval estimates. The primary endpoint is a participant count, but no model or over-dispersion assessment is reported in the registry record; therefore, no claim about its relevance to the reported analysis can be made.

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("Patients Need Head CT According to Falls Decision ", "Patients do Not Need Head CT According to Falls De")
n      <- c(559, 241)
events <- c(48, 1)
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  Patients Need Head CT According to Falls Decision   559  48  8.6  6.4  11.2  6.5  11.2  6.5  11.2
ARM  Patients do Not Need Head CT According to Falls De  241  1  0.4  0.0  2.3  0.1  2.3  0.1  2.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures and 6 analyses. Multiple outcomes or analyses can create multiplicity: when many statistical questions are examined, the chance of at least one apparently notable result may increase. In general, prespecifying a primary outcome and an analysis plan helps readers distinguish the main question from secondary or exploratory findings. The registry identifies a primary outcome and two secondary outcomes, but any multiplicity adjustment, testing hierarchy, or distinction between confirmatory and exploratory analyses is not reported in the registry record.

Missing-data handling is also not reported in the registry record. In general, missing outcome information can affect both the number of participants included and the validity of estimates, particularly if missingness is related to health status or the observed rule classification. The registry lists enrollment as 800, but does not report how many participants completed follow-up, had outcome data, or were included in each analysis. No imputation approach, complete-case rule, or sensitivity analysis for missing information is described.

Analysis populations are not reported in the registry record. It is not stated whether all enrolled participants were included, whether any eligibility or evaluability criteria were applied after enrollment, or how unavailable or indeterminate rule classifications were handled. These details are important for a validation study because excluding participants can change the population to which an accuracy estimate applies.

The registry also does not report an interim-analysis plan, stopping rule, or details of statistical monitoring. That absence should be read as information not reported in the registry record, not as evidence that a particular approach was or was not used.

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

The record supports a description of the study's purpose and target population: external validation of the Falls Decision Rule among patients aged 65 years and over who came to the emergency department after a specified fall within the last 48 hours. It also defines the primary endpoint as clinically important intracranial bleeding identified through 42 days, with medical and surgical intervention criteria. These details clarify what the investigators intended to evaluate.

The record does not report the primary endpoint result or diagnostic-accuracy estimates. It therefore cannot establish how well the rule distinguishes patients with and without clinically important bleeding, how often it misses an event, or how precisely those quantities are estimated. It also cannot show from the posted results whether use of the rule would reduce CT use, since CT use and the rule's classification outcomes are not reported.

The record's status of COMPLETED does not supply those missing results. Nor does the listed enrollment of 800 establish the number analyzed or the completeness of follow-up. The death counts listed by CIIB status are not a substitute for the primary endpoint analysis and do not establish causation. The record does not describe a randomized comparison, so it does not support an interpretation of treatment effects.

In general, a validation result applies most directly to the population, setting, outcome definition, and procedures used in the validation. Extending a result to other groups or settings requires evidence that the rule performs adequately there. In this case, numerical performance and the details needed to judge transportability are not reported in the registry record. The defensible conclusion is that the registry describes a completed external-validation study and its intended outcome, while leaving the central statistical results unavailable.

13. Why This Trial Matters Statistically

Decision rules are statistical tools for translating patient information into classifications that can support clinical decisions. Their value depends not only on how often they classify correctly, but also on the consequences of missed cases and unnecessary testing. For a rule intended to help exclude intracranial bleeding, performance on the clinically important endpoint is central. The registry identifies that endpoint and specifies an extended follow-up period that includes delayed hemorrhage.

External validation matters because a rule's performance in its development setting may not carry over unchanged to a new population or clinical context. A validation study can reveal whether the rule retains useful discrimination and whether its classifications are sufficiently precise for the intended purpose. The registry describes this purpose for geriatric patients presenting after a fall, but does not report the performance statistics needed to evaluate it.

The statistical distinction between a study objective and its result is important. A completed study is not, by itself, evidence that the rule was accurate or that CT can be avoided safely. Readers need outcome counts, classification results, and uncertainty estimates to assess the balance between identifying clinically important events and excluding patients without them. Those results are not reported in the registry record.

The entry is still informative about the target population, the Falls Decision Rule, the primary endpoint definition, and the follow-up window. It also makes clear that the study is not described as a randomized comparison. These design features help frame the question and the kinds of conclusions that could be drawn if results were available. For statistical interpretation, the unresolved gap is the absence of the main validation estimates and their precision.

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 of interpretation is that the registry record does not report the primary outcome count or the diagnostic-accuracy results. Without the rule classifications linked to outcome status, the central external-validation question cannot be answered from the posted information. Sensitivity, specificity, predictive values, confidence intervals, and any threshold-based assessment are not reported in the registry record.

The population and procedures are described only at a broad level. The record specifies age, types of fall, and presentation within the last 48 hours, but does not report detailed recruitment procedures, participant characteristics, the rule's full criteria, or how clinicians applied it. It also does not describe how the reference assessment was conducted or whether outcome determinations were independently reviewed. These details are not reported in the registry record and would matter when evaluating reproducibility and possible sources of bias.

Enrollment is listed as 800, but the number with complete follow-up, the number included in each analysis, and the handling of missing or indeterminate information are not reported. The analysis plan, analysis populations, and any adjustment or sensitivity analyses are also not reported in the registry record. Consequently, precision, completeness, and robustness cannot be assessed.

The entry lists deaths by CIIB group but does not provide sufficient context to interpret those counts as a comparative mortality result. The study is not presented as a randomized comparison, and allocation is not stated. The record therefore does not support causal conclusions about the rule or any intervention. Finally, registry completion status alone does not establish that all outcomes were measured or that the intended analysis was performed as planned.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Validation of Falls Decision Rule to Exclude Intracranial Bleeding in Geriatric Fall Patients — NCT06525727.
• Registry record last updated 2026-01-22; status last verified 2026-01.
• Results first posted 2025-07-30.
• 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.

18. Record Summary

The registry record describes NCT06525727, titled “Validation of Falls Decision Rule to Exclude Intracranial Bleeding in Geriatric Fall Patients,” sponsored by Marmara University. It lists enrollment of 800, a start date of 2024-01-20, a primary completion date of 2024-10-01, and status COMPLETED.

The study is an external validation of the Falls Decision Rule in patients aged 65 years and over presenting to an emergency department after a specified fall within the last 48 hours. The primary outcome is clinically important intracranial bleeding identified within 42 days. Secondary outcomes concern neurosurgical intervention and mortality.

The registry does not report the primary endpoint count, diagnostic-accuracy estimates, or confidence intervals. It lists 3 outcome measures and 6 analyses, but the analysis methods, missing-data handling, and analysis populations are not reported in the registry record. The entry therefore establishes the study's stated question and design context, but not its main statistical findings.