CTEPH Identification an Standard Computerised Tomography Pulmonary Angiography in Pulmonary Embolism Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for CTEPH Identification an Standard Computerised Tomography Pulmonary Angiography in Pulmonary Embolism Patients (NCT03083093), a registered phase not stated study. The primary outcome is To Identify the Accuracy of Routine CTPA for the Distinction of CTEPH From Acute PE..

2. Clinical Question

The central question concerns diagnostic discrimination: whether features on an initial scan obtained during work-up for suspected PE can help separate patients later diagnosed with CTEPH from those in whom CTEPH was excluded. The registry’s primary objective names accuracy, and its outcome description defines sensitivity among patients with confirmed CTEPH and specificity among those without CTEPH.

This distinction matters because sensitivity and specificity address different parts of the classification task. Sensitivity describes how often scans in the CTEPH group are read as positive for the specified pattern. Specificity describes how often scans in the non-CTEPH group are read as negative. Neither measure, on its own, describes how likely a positive or negative scan is to correspond to a diagnosis in a particular clinical population.

The registry does not report the number of positive scans, the number of negative scans, or the estimated sensitivity and specificity. It therefore does not establish from the posted results how well the scan review separated the groups. The focus is on the diagnostic question and the definitions used, rather than on an unreported estimate of performance.

3. Trial Design

NCT03083093 is a completed diagnostic-test study sponsored by Leiden University Medical Center. Its registry enrollment is 100. The record gives a start date of 2017-05-01 and a primary completion date of 2018-03-01. The intervention is review of the initial CTPA scan, and the stated timeframe for the primary outcome is 1 year.

The record describes two diagnostic groups. In the CTEPH group, the initial scan is reviewed in patients diagnosed with CTEPH after an episode of acute PE. In the non-CTEPH group, the initial scan is reviewed in patients after acute PE in whom CTEPH was excluded. The groups are therefore defined by diagnostic status, not by randomized assignment to treatments. The registry explicitly cautions that this is not a randomized comparison and that the arms are not a like-for-like control comparison.

The study question is whether a radiological pattern on a routine scan can distinguish these diagnostic groups. This is different from testing whether one treatment changes an outcome relative to another treatment. Interpreting a diagnostic comparison depends on how participants were selected, how diagnoses were established, and how scan readings were made. Details such as the reading procedure, reader masking, eligibility criteria, and diagnostic adjudication are not reported in the registry record.

The record lists one outcome measure and no analyses. It does not report a completed analysis of the diagnostic endpoint, the number of participants included in that analysis, or the results by group. The registry status is COMPLETED, but that status alone does not supply an estimate of diagnostic accuracy. Enrollment describes the registered study size; it should not be treated as the number contributing to a particular analysis when analysis-specific counts are not reported.

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 To Identify the Accuracy of Routine CTPA for the Distinction of CTEPH From Acute PE., measured over 1 year.

The primary outcome is titled as the accuracy of routine CTPA for distinguishing CTEPH from acute PE. Its unit is listed as sensitivity, with a 95% confidence interval, and the stated timeframe is 1 year. The outcome description also defines specificity: sensitivity is the proportion of scans read as positive for the CTEPH-specific radiological pattern among patients with confirmed CTEPH, while specificity is the proportion read as negative among patients without CTEPH.

These measures are used to describe different aspects of a diagnostic test’s classification performance. Sensitivity concerns detection within the group that has the condition of interest. Specificity concerns correct negative classification within the group without that condition. Reporting both helps make clear whether the assessment is focused on positive or negative classifications; one measure cannot substitute for the other.

A confidence interval communicates uncertainty around an estimate. In general, it gives a range of values compatible with the data and the estimation procedure, rather than a guarantee that the true value lies in that particular interval. The registry specifies a 95% confidence interval as the dispersion measure but does not report an interval or point estimate for sensitivity or specificity.

The registry also labels the outcome as a mean of a continuous measure. That label does not align transparently with the outcome description, which defines sensitivity and specificity as proportions. The record does not explain this coding or provide results that would resolve the ambiguity. Accordingly, the endpoint definitions can be described, but the observed diagnostic performance cannot be quantified from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Diagnostic accuracy is assessed by comparing a test classification with a participant’s diagnostic status. In this study, the classification of interest is whether the initial CTPA scan is read as positive for a CTEPH-specific radiological pattern. The registry describes patients with CTEPH as the group in which sensitivity is evaluated and patients without CTEPH as the group in which specificity is evaluated.

In general, sensitivity is the proportion of people with the condition of interest whose test result is positive. Specificity is the proportion of people without the condition whose test result is negative. These measures condition on diagnostic status. They are not the same as the probability of having CTEPH after a positive scan, or the probability of not having CTEPH after a negative scan. Those latter probabilities depend on the composition of the population being assessed as well as test performance.

A confidence interval is an estimate of statistical uncertainty around a point estimate. In general, narrower intervals indicate greater precision under the chosen method and its assumptions, while wider intervals indicate less precision. The registry names a 95% confidence interval for the primary measure, but it does not report a point estimate or interval. Without the observed counts or estimates, neither performance nor precision can be evaluated.

The record labels the outcome as a mean of a continuous measure while describing sensitivity and specificity as proportions. These are not naturally the same kind of summary: a mean ordinarily summarizes a numeric measurement, whereas sensitivity and specificity summarize classifications. The registry does not explain the use of the mean label. This inconsistency should be kept in mind when interpreting the endpoint description; no result is posted that would clarify how the outcome was analyzed.

The design described is a comparison between diagnostic groups, not a randomized allocation of participants to alternative interventions. General principles of diagnostic-test evaluation emphasize the importance of defining the reference diagnosis and applying the test interpretation consistently. Masking of scan readers to diagnostic status, the process used to establish or exclude CTEPH, and any adjudication procedures are not reported in the registry record. Their absence from the record does not establish that these procedures were or were not used.

In general, selection of participants can influence diagnostic accuracy estimates if the study groups do not represent the patients in whom the test would be used. The registry gives the broad group definitions but does not report detailed selection criteria or the clinical spectrum of participants. It also does not report how many scans were technically adequate, whether repeat readings occurred, or whether any participants were excluded from the endpoint analysis. These omissions prevent a reader from assessing the analysis population and the potential effect of exclusions.

The sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such illustrations are planning calculations, not observed power and not proof that a study can detect an effect. The record does not report the observed effect needed to interpret those illustrations, nor does it report a trial-specific sample-size justification. The illustrations therefore cannot establish the study’s precision or whether its enrollment was adequate for a particular diagnostic-accuracy target.

Over-dispersion is a general concern when observed variability exceeds what a statistical model assumes; if ignored, uncertainty can be understated. The registry does not report a model or a dispersion assessment for this endpoint, so no conclusion about over-dispersion in this study is possible. More broadly, the record lists no analyses, and an analysis plan, covariate adjustment, subgroup strategy, and interim analyses are not reported in the registry record. Those methods should not be inferred from the endpoint label or from the study’s completed status.

Finally, the registry’s stated timeframe is 1 year, but the record does not explain the timing of the CTEPH diagnosis relative to scan review or specify the exact endpoint assessment schedule beyond that timeframe. A diagnostic estimate depends on a clear relationship between the scan result and the reference diagnosis. The available description establishes the broad question and definitions, but does not provide enough procedural detail to independently reconstruct the analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no analyses. It does not report a multiplicity adjustment, a hierarchy of outcomes, or a strategy for handling multiple statistical tests. With no analyses posted, the registry record does not establish whether additional comparisons were performed outside the listed outcome measure.

Missing-data methods are not reported in the registry record. The number of participants with an available scan reading and a confirmed diagnostic classification is not stated, and the record does not give an endpoint-specific analysis population. It also does not say whether any scans or participants were excluded, how incomplete readings were handled, or whether any imputation was used. These details matter because diagnostic accuracy estimates depend on the classifications included in their denominators.

The registry enrollment is 100, but enrollment alone does not show how many participants contributed to each endpoint calculation. The safety record lists 50 at risk in each group, but those safety counts should not be assumed to be the primary endpoint denominators. The number analyzed for sensitivity and specificity is not reported in the registry record.

The record does not report interim analyses, a prespecified statistical analysis plan, or analysis-population definitions. It is therefore not possible to determine from the registry entry whether the posted endpoint definitions were the only planned analyses or how any departures from a plan were handled. No inference about these unreported procedures is warranted.

11. 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 reports safety figures separately for CTEPH patients and non-CTEPH patients. Each group has 50 participants listed at risk. For each group, the recorded counts are 0 participants with serious events, 0 with other events, and 0 deaths. No serious-event terms are listed.

These are the counts recorded in the registry, not evidence that no adverse events occurred in every participant or that the diagnostic procedure has been shown to be risk-free. The record does not describe how events were collected, the period of safety follow-up, or whether the counts refer to events judged related to scan review. It also does not present a randomized safety comparison. The groups are defined by CTEPH status, and the registry cautions that they are not like-for-like controls.

Accordingly, the figures should be read narrowly: the registry records zero serious events, zero other events, and zero deaths in the listed safety groups, with 50 at risk in each. The record does not provide further detail that would support broader conclusions about safety or comparative risk.

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

The registry establishes that the study was designed to examine whether routine CTPA scans, reviewed for a CTEPH-specific radiological pattern, could distinguish patients diagnosed with CTEPH after acute PE from patients in whom CTEPH was excluded. It specifies sensitivity and specificity as the relevant diagnostic concepts and names a 95% confidence interval for the primary measure.

It does not report the estimated sensitivity, specificity, confidence intervals, or the underlying scan classifications. Therefore, the posted record cannot show how often the pattern was detected in the CTEPH group, how often it was absent in the non-CTEPH group, or how precise either estimate was. The absence of those results is not evidence that the test did or did not perform well.

Even when diagnostic accuracy estimates are available, they describe performance in the participants studied and do not automatically establish performance in every setting. In general, the clinical meaning of positive and negative classifications also depends on the population in which the test is used. The registry does not report predictive values or enough population detail to assess that broader application.

The record also does not establish whether scan readers were masked, how CTEPH status was confirmed or excluded, or how missing and excluded scans were handled. Such design and analysis details are important when judging whether a diagnostic comparison is credible and applicable. Their status is not reported in the registry record and should not be inferred.

The listed enrollment and safety counts provide context about the registered study and recorded events, but they do not substitute for primary diagnostic results. The most defensible conclusion is limited: NCT03083093 records a completed diagnostic investigation with a defined question and outcome description, while its registry entry does not report the primary accuracy findings needed to answer that question.

13. Why This Trial Matters Statistically

This study’s statistical question is about classification rather than treatment effect. That distinction matters because diagnostic accuracy requires separate attention to performance among people with and without the condition of interest. Sensitivity and specificity address those two groups, while a single summary labeled “accuracy” may not communicate both aspects. The registry’s description makes both concepts relevant, although it lists sensitivity as the outcome unit.

Confidence intervals are also central to interpretation. A point estimate alone can conceal substantial uncertainty, particularly when the number of informative observations is limited. The registry specifies a 95% confidence interval, but does not report the estimate or interval. As a result, neither the magnitude nor precision of the proposed diagnostic performance can be evaluated from the record.

The nonrandomized group structure is important statistically. Patients are classified by whether CTEPH was diagnosed or excluded, rather than assigned to alternative interventions. This is appropriate to the stated diagnostic question, but it means that interpretation depends on group selection, diagnostic confirmation, and scan-reading procedures. The registry itself cautions that the arms are not like-for-like controls, and it does not provide enough procedural detail to assess those issues further.

The record also illustrates why outcome definitions and analysis labels should be read together. It describes sensitivity and specificity as proportions, while labeling the outcome as a mean of a continuous measure. Since no analyses or estimates are reported, the apparent mismatch cannot be resolved from the registry entry. This limits reproducibility and clarity about the planned statistical summary.

Finally, a completed status is not equivalent to a posted result. A diagnostic study can be registered and completed while the registry record still lacks the outcome estimates needed for statistical interpretation. Here, the central value of the record is its description of the question and intended measures; it does not support a conclusion about the measured accuracy of CTPA review.

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 primary limitation for interpretation is that no sensitivity, specificity, confidence interval, or underlying classification count is reported in the registry record. The central diagnostic question therefore cannot be answered from the posted results. Although the record names a 95% confidence interval, it gives no estimate to which that interval would apply.

The endpoint description and coding are not fully aligned. The outcome is labeled as a mean of a continuous measure, while its narrative definition describes sensitivity and specificity as proportions. The registry does not explain this discrepancy. The outcome title refers to accuracy, while the listed unit is sensitivity and the description additionally defines specificity. Without reported analyses, it is unclear how the planned summaries were operationalized.

The study groups are defined by CTEPH diagnostic status and are not randomized, as the registry explicitly notes. The record does not report detailed selection criteria, the method of confirming or excluding CTEPH, scan-reader masking, or the process for resolving uncertain readings. These omissions prevent assessment of potential selection and measurement biases. They do not establish that such safeguards were absent; their use is not reported in the registry record.

Analysis-specific denominators and missing-data handling are also not reported. Enrollment is 100, but the record does not state how many participants contributed to each diagnostic measure. The safety group counts should not be assumed to be endpoint denominators. The record also does not describe exclusions, inadequate scans, or incomplete diagnostic classifications.

Finally, the registry does not report an analysis plan, a trial-specific sample-size justification, or interim analyses. Its planning-illustration assumptions do not provide an observed diagnostic result or establish the precision achieved. These limitations mean that the record supports a description of the intended diagnostic evaluation, not an independent appraisal of its numerical findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: CTEPH Identification an Standard Computerised Tomography Pulmonary Angiography in Pulmonary Embolism Patients — NCT03083093.
• Registry record last updated 2021-04-19; status last verified 2021-03.
• Results first posted 2021-02-25.
• 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

NCT03083093, sponsored by Leiden University Medical Center, is listed as COMPLETED. The registry gives enrollment of 100, a start date of 2017-05-01, and a primary completion date of 2018-03-01. The intervention is review of the initial CTPA scan in groups with and without CTEPH after acute PE.

The primary question concerns identification of a CTEPH-specific radiological pattern. The outcome description defines sensitivity and specificity and names a 95% confidence interval, with a timeframe of 1 year. The record lists one outcome measure and no analyses; it does not report the primary diagnostic estimates or their precision.

Safety data list 50 participants at risk in each group, with zero serious events, zero other events, and zero deaths recorded in both groups. The registry cautions that the diagnostic groups are not randomized, like-for-like controls. Overall, the record describes the study’s diagnostic objective but does not report the results needed to quantify CTPA accuracy.