ENB-GS-TBLB for the Diagnosis of PPLs: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for ENB-GS-TBLB for the Diagnosis of PPLs (NCT02207478), a randomized na study. The primary outcome is The Difference of Diagnostic Value of ENB-GS-TBLB as Compared to GS-TBLB.

2. Clinical Question

The question is about diagnostic yield, not a comparison of long-term health outcomes. The registry describes the primary outcome timeframe as up to half year, but does not provide further detail about when or how diagnostic status was established. The record also names a secondary outcome concerning the difference in procedure duration. A numerical result for that outcome is not reported in the registry record.

3. Trial Design

This was a randomized, parallel-group trial with no masking. Its listed enrollment was 80, and its status is completed. The registry gives a start date of 2014-07 and a primary completion date of 2015-03. Shanghai Chest Hospital is listed as the sponsor. The phase is listed as NA.

Participants were assigned to one of two procedure groups. In the ENB-GS-TBLB-X-ray group, electromagnetic navigation was used to introduce the guide sheath toward the lesion. The location of the guide and sheath was confirmed with radiograph fluoroscopy, and pathologic specimens were obtained with fluoroscopic guidance. In the GS-TBLB-X-ray group, the guide sheath was passed through the bronchoscope working channel. Fluoroscopy was used to identify the lesion location, and specimens were then obtained under fluoroscopic guidance.

Randomized allocation can reduce systematic differences between groups when assignment is carried out appropriately. However, the method used to generate the allocation sequence, conceal assignments, or handle departures from assigned procedures is not reported in the registry record. The record identifies the trial as unmasked; it does not explain whether outcome assessors or pathologists were masked.

The safety results list 39 participants at risk in the ENB-GS-TBLB-X-ray group and 41 in the GS-TBLB-X-ray group. These are the populations shown for the adverse-event outcomes; the registry does not explain whether they represent all randomized participants or define the analysis population for the primary outcome. The primary analysis population and the numbers included in each diagnostic-yield calculation are not 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 The Difference of Diagnostic Value of ENB-GS-TBLB as Compared to GS-TBLB, measured over Up to half year.

The primary endpoint is described as the difference in diagnostic value between ENB-GS-TBLB and GS-TBLB. The registry expresses the result as diagnostic yield and reports 87.2% for the ENB-GS-TBLB group and 61% for the GS-TBLB group. The stated unit for the outcome is participants, and the timeframe is up to half year.

Diagnostic yield is used in general to describe how often a diagnostic procedure produces a result that meets a specified definition of successful diagnosis. It is a binary outcome when each participant is classified as meeting or not meeting that definition. The registry record does not specify the exact criteria for a successful diagnosis, how nondiagnostic or inconclusive specimens were classified, or whether diagnostic status was confirmed against later clinical information. Those details matter because different definitions can produce different yield estimates.

The reported percentages describe the groups, but do not by themselves show how precisely the yields were estimated or whether a between-group difference is compatible with chance variation. A confidence interval would describe the uncertainty around an estimate, while a formal comparison would quantify evidence about the difference under a specified statistical model. Neither is reported in the registry record. The record also flags that the primary outcome has several categories or time points and is not reduced to one comparison, so the stated yields should not be treated as a complete account of all outcome data.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is diagnostic yield?

In general, a binary outcome classifies each participant into one of two states, such as meeting or not meeting a prespecified diagnostic-success criterion. A yield percentage summarizes the proportion meeting that criterion in a group. To interpret such a percentage, readers need the numerator, denominator, endpoint definition, and rules for missing or indeterminate results. The registry reports diagnostic yields of 87.2% and 61%, and safety populations of 39 and 41, but does not give the diagnostic numerators and denominators or define the success criterion in detail.

For a binary outcome, a comparison can be expressed in several ways, including a difference in proportions, a ratio of proportions, or an odds ratio. These measures answer related but distinct questions. No such effect estimate for the primary comparison is reported in the registry record, so none should be inferred from the two yields. In particular, the descriptive percentages do not identify the statistical model, adjustment strategy, or uncertainty estimate used by the investigators.

How should uncertainty be understood?

In general, a confidence interval describes a range of values compatible with the observed data under a particular statistical method and its assumptions. Its width conveys precision: wider intervals indicate greater uncertainty, while narrower intervals indicate greater precision. A confidence interval is not reported for the primary outcome in the registry record. Nor is a p-value for the primary comparison reported. The absence of these results means that the record does not establish the precision or strength of evidence for the difference between groups.

Randomization helps make groups comparable on average, but it does not eliminate random variation. It also does not resolve problems caused by outcome misclassification, missing data, deviations from assigned procedures, or selective reporting. Details about how these issues were addressed are not reported in the registry record. The unmasked design is another feature to consider: in general, masking can reduce the influence of knowledge about assignment on assessment, although its relevance depends on the outcome and the assessment process. The record does not state whether assessors were masked.

What does the planning illustration mean?

In general, a sample-size calculation estimates how many participants may be needed to detect a specified effect under stated assumptions. The planning illustrations associated with the posted results are based on the observed effect, a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. They consider detecting a stated fraction of the observed effect. Such values are planning illustrations, not observed power and not proof that the completed trial had a particular probability of detecting an effect.

The registry does not report the trial's own sample-size justification, target effect, or design assumptions. Consequently, the posted planning illustration should not be interpreted as the original enrollment rationale. In general, a planning calculation is sensitive to the assumed effect size, significance level, allocation, and statistical method. If the true effect differs from the assumed value, the calculation may not describe the operating characteristics of the study that was actually conducted.

What can be inferred from the listed analyses?

The registry lists five analyses and two outcome measures, but does not describe how the analyses map to the outcomes, which populations were included, or whether models were adjusted. It also flags that the primary outcome has several categories or time points and is not reduced to one comparison. A single pair of yield percentages therefore may not capture every reported category or time point. The registry record does not provide enough information to reconstruct a complete analysis or to determine whether reported categories were selected in advance.

In general, a statistical analysis plan would specify the primary estimand, endpoint definition, analysis population, handling of missing observations, model, and approach to multiple comparisons. These details help distinguish prespecified analyses from exploratory ones and clarify what the uncertainty statements mean. Such a plan is not reported in the registry record. No independent recalculation or adjusted effect estimate is available in the registry entries, and no claim about statistical significance should be made from the percentages alone.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability is greater than a statistical model assumes. It matters when a model's uncertainty estimates rely on a variance assumption that does not fit the data; standard errors may then be too small and confidence intervals too narrow. That issue is not identified as an analysis feature in this record. The reported primary endpoint is described as a participant-based diagnostic yield, and the registry does not report a model or variance assessment that would allow evaluation of over-dispersion. This concept is therefore a general statistical consideration, not a claim about the trial's analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and five analyses, but does not report a detailed analysis plan linking each analysis to an outcome, time point, or participant population. It also flags that the primary outcome has several categories or time points and is not reduced to one comparison. This makes it difficult to identify which result was intended to be the single primary inferential test, or whether the reported diagnostic yields cover all outcome categories.

In general, multiplicity arises when several outcomes, time points, subgroups, or statistical tests are considered. Testing many hypotheses can increase the chance of finding an apparently notable result by chance. Statistical plans may address this with a prespecified testing hierarchy or an adjustment procedure, but the approach used in this trial is not reported in the registry record. No claim about multiplicity adjustment can therefore be made.

The registry record does not report how missing diagnostic results, indeterminate findings, withdrawals, or deviations from assigned procedures were handled. It also does not specify an intention-to-treat, per-protocol, or other analysis population for the primary endpoint. These omissions matter because the estimated yield may depend on which participants are included and how unresolved outcomes are classified. The listed safety populations do not, on their own, define the primary efficacy population.

In general, transparent reporting of missingness and analysis populations allows readers to assess whether exclusions could affect a group comparison. The record does not provide enough detail to make that assessment. It also does not report a prespecified approach to subgroup analyses or multiple outcome comparisons. The diagnostic-yield percentages should consequently be interpreted as reported group summaries, without assuming that missing data or multiplicity were handled in any particular way.

11. 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 adverse-event record lists zero serious adverse events among 39 participants at risk in the ENB-GS-TBLB-X-ray group and zero among 41 participants at risk in the GS-TBLB-X-ray group. It also lists zero other adverse events in both at-risk populations. These are the recorded counts for the safety outcomes, not a guarantee that no adverse events occurred outside the registry's definitions or observation procedures.

The record does not report the criteria used to classify events as serious or other adverse events, the duration of safety follow-up, or details about how events were collected. Death counts are not reported. The at-risk counts refer to the listed safety outcomes and should not automatically be treated as the analysis denominators for diagnostic yield.

In general, an observed count of zero does not establish that the underlying event risk is zero. The interpretation depends on the number of people observed, the completeness and duration of follow-up, and the sensitivity of event ascertainment. No further safety inference can be made from these registry figures alone. They should be read as the adverse-event counts recorded for the stated populations, with the reporting limitations kept in view.

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

The record describes a randomized comparison of two bronchoscopy procedures for diagnosing peripheral pulmonary lesions. It reports diagnostic yields of 87.2% for ENB-GS-TBLB with fluoroscopy and 61% for guide-sheath transbronchial biopsy with fluoroscopy alone. It also records zero serious and zero other adverse events in the listed safety populations. These are the main numerical observations available in the registry entry.

Those figures do not, by themselves, establish how precisely the diagnostic yields were estimated or how strong the statistical evidence is for a difference between the procedures. The registry does not report a confidence interval, p-value, or formal primary comparison. It does not provide the exact definition of diagnostic success, the underlying diagnostic counts, or the primary analysis population. The record also notes multiple categories or time points for the primary outcome without reducing them to one comparison. These gaps limit interpretation of the percentages.

The results also do not establish whether the observed yields would be similar in other populations, institutions, or practice settings. Generalizability depends on participant selection, procedural expertise, lesion characteristics, and outcome assessment, details that are not fully reported in the registry record. The unmasked design may be relevant to assessment, but the record does not describe masking of outcome assessors.

In general, a randomized design supports comparative interpretation, but its value depends on how randomization was implemented and how outcomes and missing data were handled. Those details are not reported. The record does not report a numerical result for the secondary procedure-duration outcome, and it does not report death counts. The posted information therefore supports a descriptive account of the reported yields and adverse-event counts, not a complete evaluation of uncertainty, bias, or clinical significance.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question about evaluating diagnostic procedures: a difference in observed yield is only one part of the evidence. Readers also need to know what counts as a successful diagnosis, how the result was verified, who was included in the analysis, and how uncertain the estimates are. The registry reports group-specific yields but does not report the details needed to answer all of those questions.

Randomized allocation is relevant because it can reduce systematic differences between groups. At the same time, procedural studies are difficult to mask, and the registry identifies this study as having no masking. The assessment process therefore matters: if the outcome depends on interpretation of specimens or clinical follow-up, the way that assessment was conducted should be clear. The registry does not report whether assessors were masked or describe the adjudication process.

The primary outcome is also described as having multiple categories or time points, while the reported yield values offer only a limited view of that structure. Clear prespecification and reporting are important when several outcomes or analyses are possible, because they help readers understand which comparisons were primary and how multiplicity was considered. That information is not reported in the registry record.

Finally, the adverse-event counts illustrate why a zero count must be interpreted with its observation population and follow-up context. The record lists no serious or other events in the stated at-risk groups, but does not provide event definitions or follow-up details. Statistically, the trial is informative as a randomized procedural comparison with reported yield summaries, while its registry entry leaves important questions about precision, endpoint construction, and analysis methods unresolved.

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 entry does not provide the primary outcome's full operational definition. It gives the diagnostic-yield percentages and a timeframe of up to half year, but does not specify the criteria for diagnostic success, treatment of inconclusive findings, verification procedures, or whether each participant's final diagnostic status was assessed in the same way. Without this information, the reported percentages cannot be independently interpreted against a clear endpoint rule.

The record does not report the primary outcome's participant counts, confidence interval, p-value, or a formal effect estimate. It also does not specify the primary analysis population or how missing outcomes and protocol deviations were handled. Although the study is identified as randomized, the sequence-generation and allocation-concealment methods are not reported. These omissions constrain assessment of both precision and potential bias.

The trial was unmasked, and the registry does not say whether outcome assessors or pathologists were masked. It also identifies several primary-outcome categories or time points but does not reduce them to one comparison. The analysis plan, multiplicity approach, model choice, and adjustment strategy are not reported. A secondary outcome concerns procedure duration, but its numerical result is not reported in the registry record.

Safety reporting is limited to zero serious and zero other adverse events in the listed populations of 39 and 41. The record does not give event definitions, observation duration, or death counts. It also does not report participant characteristics or detailed eligibility criteria, limiting assessment of how well the results may apply to other groups. The trial is listed as completed, but completion status does not supply the missing methodological and outcome details.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: ENB-GS-TBLB for the Diagnosis of PPLs — NCT02207478.
• Registry record last updated 2015-11-30; status last verified 2015-10.
• Results first posted 2015-11-30.
• 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

NCT02207478 is a completed, randomized, parallel-group trial sponsored by Shanghai Chest Hospital. It enrolled 80 participants and is listed as unmasked, with phase NA. The registry gives a start date of 2014-07 and a primary completion date of 2015-03.

The comparison was electromagnetic navigation bronchoscopy with a guide sheath and fluoroscopy versus guide-sheath transbronchial biopsy with fluoroscopy alone. The primary outcome concerns diagnostic value, with diagnostic yields reported as 87.2% and 61%, respectively, over a timeframe of up to half year. A secondary outcome concerns procedure duration, but its result is not reported in the registry record.

The safety record lists zero serious and zero other adverse events among 39 and 41 participants at risk in the respective groups. Death counts are not reported. The registry does not report a confidence interval or p-value for the primary comparison, a complete endpoint definition, or key details of the analysis plan and analysis populations.