Shear Wave Sonoelastography in Pediatric Liver Fibrosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Shear Wave Sonoelastography in Pediatric Liver Fibrosis (NCT02372682), a registered phase not stated study. The primary outcome is 2D-SWE Measurements' Capability of Predicting Stages of Fibrosis Based on METAVIR Scoring System.

2. Clinical Question

The study addresses a diagnostic measurement question, not a treatment comparison. The registry background describes limitations of pediatric liver biopsy and explains the interest in noninvasive methods. It also distinguishes shear wave imaging from other elastography approaches by describing tissue measurements with corresponding ultrasound images.

The clinical question therefore concerns how measurements from the imaging technique relate to fibrosis stages assessed with METAVIR. The test group was described as having known liver disease and a biopsy planned as standard care; the control group was described as having normal abdominal ultrasound findings in a different clinical setting. Because these groups were not presented as randomized, interchangeable treatment groups, differences between them cannot be interpreted as effects caused by the device.

The registry record does not report the observed percentage, the number of exams used for that endpoint, or an estimate of uncertainty. It also does not give the specific rule used to classify a measurement as predicting a fibrosis stage. Without those details, the question can be identified, but the strength and precision of the answer cannot be assessed from the registry record.

3. Trial Design

The registry lists this study as completed, with an enrollment of 171. The recorded start date is 2015-05-11, and the primary completion date is 2018-05-31. The intervention is shear wave sonoelastography, classified as a device. The study is described through test and control groups, rather than a randomized treatment allocation.

The test-arm description concerns pediatric patients with known liver disease for whom liver biopsy was to be performed as standard care. Those patients would also undergo abdominal ultrasound to evaluate the liver. The control-arm description concerns pediatric patients having abdominal ultrasound as standard care for a reason other than liver disease; those with normal findings in the listed abdominal structures could be asked to enroll. The descriptions therefore define groups with different clinical circumstances, rather than groups differing only by receipt of the imaging measurement.

The registry record does not state the allocation method. Its design information does not support treating the arms as a randomized comparison, and the groups are not a like-for-like control comparison. Any difference between their measurements or characteristics could reflect the underlying clinical differences between the groups, as well as the imaging method or other factors.

The primary endpoint has a timeframe of 2 years and is described as the percentage of exams for which 2D-SWE measurements predict fibrosis stages based on METAVIR. The record lists 2 outcome measures, but does not provide the numerical primary endpoint result in the registry record for this summary. It also lists no analyses. Details such as recruitment flow, the number of examinations included in each analysis, and the handling of repeated examinations are not reported in the registry record.

The record’s enrollment figure is a study-level figure. It should not be substituted for the denominator of the primary endpoint: the endpoint is expressed per exam, and its analysis denominator is not reported in the registry record. No randomized allocation, masking approach, or protocol-based sample-size justification is reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as 2D-SWE Measurements' Capability of Predicting Stages of Fibrosis Based on METAVIR Scoring System, measured over 2 years.

The primary endpoint is titled “2D-SWE Measurements' Capability of Predicting Stages of Fibrosis Based on METAVIR Scoring System.” Its unit is percentage of exams, and the timeframe is 2 years. METAVIR is described in the registry as a tool used to measure fibrosis as seen on liver biopsy and scored to describe liver disease progress and prognosis.

In general, an endpoint expressed as a percentage of exams is intended to describe how often a defined exam-level condition is met. For this question, that condition would need to specify what counts as a correct prediction of a METAVIR fibrosis stage. The registry description does not report the decision rule, stage categories assessed, or how agreement between the imaging measurement and biopsy stage was defined. The numerical percentage and its uncertainty are also not reported in the registry record.

Comparing the measurement with biopsy staging offers a way to assess whether an imaging-based measure corresponds to a clinical reference assessment. This is relevant to the study’s stated interest in noninvasive evaluation. However, the endpoint title alone does not establish diagnostic accuracy across all stages or clinical settings. A percentage without a stated denominator, classification rule, and uncertainty estimate does not show how stable or generalizable the result is.

The registry record describes the endpoint but does not provide an endpoint value. Consequently, it is possible to explain what the measure is intended to address, but not to quantify how often the stated prediction was achieved.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the endpoint and the study groups, but it does not report an analysis plan or endpoint result. The explanations below distinguish the information recorded for this study from general statistical principles that would be relevant to interpreting a diagnostic measurement study.

What does a percentage-of-exams endpoint represent?

In general, a percentage describes the share of observations meeting a defined condition. In this study, the observations are described as exams, and the intended condition concerns prediction of fibrosis stages based on METAVIR. To interpret such a percentage, readers need to know the exam-level rule: what measurement counts as a prediction, which stage is being predicted, and how a prediction is judged against the reference assessment. The registry record does not report these operational details or the endpoint’s numerical value.

The denominator is important because it indicates how much information underlies the percentage. It might depend on which participants had both usable imaging measurements and a biopsy stage available, but the actual analysis population and denominator are not reported in the registry record. That possibility is a general consideration, not a description of how this study handled participants or exams.

Why is uncertainty important?

In general, a confidence interval describes a range of values compatible with the observed data under the analysis assumptions. It helps readers distinguish a precise estimate from one that is uncertain. A point estimate alone can conceal substantial uncertainty, especially when the number of usable observations is limited or when observations are not independent. The registry record does not report a confidence interval or another measure of precision for the primary endpoint.

Repeated exams from the same participant, if present, would not necessarily provide independent observations. In general, treating correlated measurements as independent can make uncertainty appear smaller than it is. The registry record does not state whether participants contributed repeated exams or how any such correlation was handled, so no conclusion about this study’s approach is possible.

What is the role of the comparison groups?

In general, a randomized comparison aims to make groups comparable in expectation, allowing an outcome contrast to be attributed more credibly to assigned intervention. This registry describes test and control groups with different clinical circumstances and does not state an allocation method. The test group had known liver disease and a biopsy planned as standard care; the control group was described as having ultrasound for another reason and normal findings in listed structures. A contrast between these groups would therefore be vulnerable to differences in disease status and clinical selection. It should not be interpreted as a randomized treatment effect.

For a diagnostic study, relevant measures can include agreement with a reference assessment, sensitivity, specificity, and performance by disease stage. These are general examples, not results or analyses reported for this study. The registry record does not specify which such measures, if any, were planned or calculated. The primary endpoint title alone does not establish that all these properties were evaluated.

What do the planning assumptions mean?

The record describes a planning illustration based on the observed effect, with two-sided significance level 0.05, equal allocation between arms, and a normal approximation; it says the effect to detect is a stated fraction of the observed effect. Such an illustration explores the sample size associated with assumed conditions. It is not the trial’s own design justification, and it is not observed power. The registry record does not report a protocol-based sample-size justification. The numerical planning outputs are not reported in the record available for this summary.

In general, sample-size illustrations depend on their assumptions. Changing the target effect, variability, allocation, or significance level can change the estimate. An illustration based on an observed effect is also conditional on that effect estimate, which may itself be uncertain. It should not be treated as evidence that the study was adequately powered or that its result is conclusive.

What analysis details are missing?

The registry record lists 0 analyses and does not report a statistical analysis plan. It does not specify whether the main analysis used one exam per participant, how unusable measurements were treated, whether any covariates were considered, or how missing biopsy or imaging data were handled. These are not minor technicalities: they determine which observations contribute to the endpoint and how the estimate should be interpreted.

In general, a complete report would link each endpoint to its analysis population, denominator, prespecified calculation, uncertainty estimate, and treatment of missing observations. Without these details and the numerical endpoint result, the registry record supports a description of the study question, but not an independent assessment of the endpoint’s statistical performance.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 2 outcome measures, but does not report an analysis plan or analysis results. It does not state whether the primary endpoint was the sole confirmatory analysis, whether other outcomes were considered supportive, or whether adjustments for multiple comparisons were planned. When several outcomes or subgroup analyses are examined, the chance of a nominally notable result can increase. In general, a prespecified hierarchy or multiplicity adjustment can help clarify how such findings should be interpreted. Whether either approach was used in this study is not reported in the registry record.

Missing-data handling is also not reported in the registry record. The primary endpoint is expressed as a percentage of exams, but the record does not identify the denominator used, the number of exams with usable measurements, or whether biopsy staging and imaging were available for all eligible participants. It does not describe exclusions, indeterminate measurements, or any method for addressing incomplete observations. These omissions prevent assessment of whether the endpoint represents all enrolled participants, a subset with complete assessments, or another analysis population.

The analysis population is not reported in the registry record. The enrollment figure alone does not establish which participants or exams contributed to the primary analysis. Nor does the record state whether repeated exams were possible or how within-participant dependence would have been considered. These details affect both the interpretation of the estimated percentage and its precision.

Accordingly, no conclusion can be drawn about multiplicity control, missing-data bias, or the comparability of the analysis population with the enrolled population. These are reporting gaps, not evidence that a particular method was or was not used in practice.

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 lists serious adverse event figures separately for the Test and Control groups. For Test, it records 70 at risk, 0 affected, and 0 deaths. For Control, it records 79 at risk, 0 affected, and 0 deaths. The corresponding entries for other adverse events list 70 at risk and 0 affected for Test, and 79 at risk and 0 affected for Control.

These entries mean that the registry record reports no affected participants in the listed serious or other adverse-event fields. They should not be read as proof that no event could occur or that all harms were excluded. The registry record does not report the event definitions, surveillance approach, duration of safety follow-up, completeness of reporting, or whether the at-risk figures represent the same population used for the primary endpoint.

The study is not described as a randomized comparison, and the groups differ in their clinical descriptions. The safety figures therefore do not support a causal comparison between the groups. They are descriptive registry entries. The record also does not list serious adverse event terms, so no specific event type can be characterized from those fields.

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

The registry record establishes that a completed pediatric study evaluated shear wave sonoelastography in relation to liver fibrosis staging. Its primary endpoint concerns the percentage of exams for which 2D-SWE measurements predict METAVIR stages, with a stated timeframe of 2 years. This defines the intended measurement question, but the numerical result is not reported in the registry record.

That missing result means the record does not establish how often the prediction criterion was met. It also does not establish how precise the estimate was, whether performance differed by fibrosis stage, or how the method compared with another diagnostic approach. The endpoint’s wording should not be treated as a conclusion that prediction was successful; it states what the study set out to assess.

The group structure also limits what can be inferred from comparisons. Test participants were described as having known liver disease and a biopsy planned as standard care. Control participants were described as undergoing ultrasound for a different clinical reason and having normal findings in listed structures. The record does not report random allocation. Any group contrast could reflect these differences in clinical context rather than the measurement technique.

The registry record does not report the analysis plan, analysis population, endpoint denominator, missing-data approach, or uncertainty estimate. Therefore, it does not permit a full appraisal of statistical reliability or generalizability. The enrollment figure of 171 describes the study’s recorded enrollment, but it cannot be assumed to equal the number of exams included in the primary endpoint.

The adverse-event entries report 0 affected for serious events and 0 deaths in each group, as well as 0 affected for other adverse events. These records are descriptive and do not show that all possible events were excluded or that follow-up and ascertainment were complete.

In short, the registry record identifies a clinically relevant diagnostic question and records study completion, but it does not provide the primary numerical result needed to judge what the study found. No conclusion about the performance of the imaging measurement should be drawn from the endpoint title alone.

13. Why This Trial Matters Statistically

This study matters statistically because it asks how an imaging measurement relates to a reference assessment of fibrosis in a pediatric population. Diagnostic measurement questions require more than a statement that an imaging technique was evaluated. Readers need a clearly defined prediction rule, a suitable reference standard, an interpretable denominator, and an estimate of uncertainty.

The registry’s endpoint is expressed as a percentage of exams and uses METAVIR staging as its reference framework. That framing highlights the importance of linking exam-level measurements to biopsy-based stages. The record, however, does not report the result, denominator, classification rule, or precision. Those omissions mean the statistical evidence cannot be judged from the endpoint description alone.

The study also illustrates why comparison-group selection matters. The test and control descriptions reflect different clinical contexts: known liver disease with biopsy planned for the test group, and ultrasound for another reason with normal findings in the control group. Without stated random allocation and comparable groups, differences between arms cannot be read as the effect of an intervention. For diagnostic evaluation, the relevant question is the relationship between each measurement and the reference standard, not simply whether group averages differ.

Finally, completeness of analysis reporting matters. The registry record lists 0 analyses and does not describe missing-data methods, analysis populations, or multiplicity handling. These details govern how an endpoint should be interpreted and how much confidence to place in it. The record’s enrollment and safety entries do not fill those gaps.

The statistical importance of the study is therefore in its stated diagnostic aim and in the reporting requirements needed to evaluate that aim. A clear result with its denominator, uncertainty, and analysis details would be necessary to assess the measurement’s observed performance.

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 registry record does not report the numerical primary endpoint result, its denominator, or a measure of precision. It identifies the outcome as a percentage of exams but does not define the prediction rule or explain how imaging measurements were matched to METAVIR stages. This prevents quantitative assessment of the main objective.

The arm descriptions indicate clinically different groups. The test group involved known liver disease and a biopsy planned as standard care, whereas the control group involved ultrasound for another reason and normal findings in listed structures. The record does not state a randomization method, and these groups should not be treated as exchangeable controls. The descriptions are also incomplete in the record text available for this summary.

The statistical analysis plan, analysis population, missing-data methods, and handling of repeated exams are not reported in the registry record. The record lists 0 analyses, so it does not provide information about any adjustment, subgroup evaluation, or sensitivity analysis. It also does not report a protocol-based sample-size justification.

The safety fields report no affected participants in the listed serious or other adverse-event categories, but the record does not explain event ascertainment or follow-up completeness. The at-risk figures should not be assumed to be the endpoint denominator.

These limitations concern what can be assessed from the registry record. They do not establish that an analysis or procedure was not performed; they indicate that the relevant information is not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Shear Wave Sonoelastography in Pediatric Liver Fibrosis — NCT02372682.
• Registry record last updated 2019-09-12; status last verified 2019-08.
• Results first posted 2019-09-12.
• 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 a completed study titled “Shear Wave Sonoelastography in Pediatric Liver Fibrosis,” sponsored by St. Louis University. It records enrollment of 171, a start date of 2015-05-11, and a primary completion date of 2018-05-31. The intervention is shear wave sonoelastography.

The primary endpoint concerns the capability of 2D-SWE measurements to predict fibrosis stages based on METAVIR, expressed as a percentage of exams over 2 years. The numerical result, endpoint denominator, and statistical analysis plan are not reported in the registry record. The record lists 2 outcome measures and 0 analyses.

The test and control groups have different clinical descriptions, and the record does not state a random allocation method. Safety fields list 0 serious adverse events affected and 0 deaths in each group, as well as 0 other adverse events affected in each group. These entries do not establish complete safety ascertainment.