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 Acetic Acid Chromoendoscopy to Judge Gastric Intestinal Metaplasia (NCT01499576), a na na study. The primary outcome is Percent Agreement Between Acetic Acid Chromoendoscopy and Endoscopic Biopsy.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01499576 |
| Phase | NA |
| Condition | Stomach Neoplasms, Metaplasia |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 126 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Konyang University Hospital |
| Results posted | Yes |
2. Clinical Question
Population
People undergoing evaluation for gastric intestinal metaplasia (IM) were the focus. The registry lists an enrollment of 126, but does not report the characteristics of the enrolled participants or the number included in the primary analysis.
Intervention
Acetic acid chromoendoscopy: acetic acid was sprayed during endoscopy, and the endoscopist judged the presence and extent of gastric IM based on the endoscopic appearance.
Comparator
Endoscopic biopsy served as the comparison for the primary endpoint. The description says the endoscopist performed five biopsies according to the protocol, and a pathologist reviewed the biopsy slides.
Primary question
How closely did judgments from acetic acid chromoendoscopy agree with judgments based on endoscopic biopsy? The endpoint was percent agreement between the methods, expressed as a percentage of lesions.
The clinical motivation described in the registry is that the presence and extent of gastric IM can help identify people at higher risk of gastric cancer. The investigators sought to assess whether acetic acid spraying could make IM visible through whitish discoloration and whether this appearance could support judging its presence and extent. The registry says that accuracy, sensitivity, and specificity were study aims, but it names percent agreement between chromoendoscopy and biopsy as the primary endpoint.
This is a diagnostic-method question, not a treatment comparison. The record describes a single-group study and does not report a separate control group. The central issue is how similar the endoscopic assessment was to the biopsy assessment in this study, rather than whether the procedure changes health outcomes. The registry record does not report the observed agreement, sensitivity, or specificity, so the clinical question is clear but its numerical answer cannot be read from the posted results.
3. Trial Design
This was a prospective, single-group study of acetic acid chromoendoscopy for judging the presence and extent of gastric intestinal metaplasia. The registry lists the study as completed, with enrollment of 126. It records a start in 2011-11 and primary completion in 2012-03. The intervention is described as a procedure, with the group identified as acetic acid spraying.
There was no randomized comparison: the allocation is listed as not applicable, and the study model is single group. The record also lists masking as none. These design features mean the study is not a like-for-like comparison of two assigned groups. Instead, the primary analysis was intended to compare judgments made with acetic acid chromoendoscopy against biopsy assessments within the study.
According to the endpoint description, an endoscopist judged the presence and extent of gastric IM during chromoendoscopy and performed five endoscopic biopsies according to the protocol. A pathologist reviewed the biopsy slides, with the endpoint timeframe described as 3 months after completion of the study. The secondary outcomes listed are agreement between the two endoscopists and the number of participants with adverse events.
The registry record does not report eligibility criteria, participant characteristics, the number who completed the procedure, or the number included in each analysis. It also does not report the sample-size justification, detailed conduct of the endoscopic assessments, or the analysis population. The enrollment figure should therefore not be read as the number contributing to every outcome. The posted information supports describing the study structure and its planned assessment, but not reconstructing unreported operational or statistical details.
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 | Acetic Acid Spraying |
|---|---|
| STARTED | 126 |
| COMPLETED | 105 |
| NOT COMPLETED | 21 |
Reasons for not completing this period:
| Reason | Acetic Acid Spraying |
|---|---|
| Physician Decision | 12 |
| Withdrawal by Subject | 9 |
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.
| Characteristic | Unit | Acetic Acid Spraying |
|---|---|---|
| Participants analysed | 105 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 96 |
| Age, Categorical: >=65 years | Participants | 9 |
| Age, Continuous | years | 50.9 (SD 9.3) |
| Sex: Female, Male: Female | Participants | 52 |
| Sex: Female, Male: Male | Participants | 53 |
| Region of Enrollment: Korea, Republic of | participants | 105 |
6. Primary Endpoint
The registry lists the primary outcome as Percent Agreement Between Acetic Acid Chromoendoscopy and Endoscopic Biopsy, measured over 3 months after the completion of the study (a pathologist reviewed all the biopsy slide).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of lesions |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was percent agreement between acetic acid chromoendoscopy and endoscopic biopsy. The registry defines the unit as a percentage of lesions. During chromoendoscopy, the endoscopist judged whether gastric intestinal metaplasia was present and assessed its extent. Biopsies were taken according to the protocol, and a pathologist reviewed the slides. The endpoint was intended to summarize how often these assessments corresponded.
Agreement is useful for describing consistency between two assessment methods. It is not automatically the same as diagnostic accuracy: agreement alone does not show how well a method identifies disease relative to a definitive reference, and it may depend on how common the finding is in the assessed lesions. The registry mentions accuracy, sensitivity, and specificity as aims, but does not report their results in the record.
The endpoint could help readers understand whether the endoscopic appearance and biopsy assessment tended to give the same classification in this study. Its interpretation would depend on how lesions were defined, how extent was categorized, and how disagreement was handled. Those details are not reported in the registry record. The primary agreement result itself is also not reported in the registry record, so the endpoint's purpose can be described, but its observed magnitude and precision cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record makes the intended comparison understandable: the study assessed whether judgments from acetic acid chromoendoscopy corresponded with findings from endoscopic biopsy. It also identifies percent agreement between the methods as the primary endpoint. However, the record does not report the observed percent agreement. It therefore does not show, in numerical terms, how often the two assessment approaches matched or how precisely that agreement was estimated.
The brief summary refers to a pilot study in which the investigators reported accuracy greater than 80%. That statement is background in the registry description, not a result of the current study. It should not be substituted for the missing primary endpoint or treated as evidence of this study's performance. The record's stated objectives also include accuracy, sensitivity, and specificity, but their estimates are not reported in the registry record.
Agreement and diagnostic accuracy answer related but distinct questions. Agreement describes whether assessments match; accuracy, sensitivity, and specificity require a defined reference classification and an appropriate analysis. Even when a biopsy assessment is used as the comparison, the interpretation depends on the biopsy and reading procedures, the classification rules, and how lesions are linked to assessments. The record provides some procedural context, including five biopsies and pathologist review, but does not report enough detail to evaluate these aspects fully.
The trial is single group and has no randomized control comparison. Its data therefore address a method-comparison question, not a causal effect of one intervention relative to another. No conclusion about clinical benefit, downstream outcomes, or cancer risk can be drawn from the endpoint described. The registry's title and rationale identify the intended application, but the posted record does not supply outcome findings that would establish the method's performance in the enrolled study population.
Enrollment was 126, while the adverse-event group lists 105 participants at risk. These are different reported figures attached to different parts of the record; the reason for the difference is not reported in the registry record. The enrollment should not be assumed to be the analysis denominator for the primary endpoint. The number of lesions assessed, the number of participants with evaluable biopsy and chromoendoscopy results, and the handling of missing assessments are also not reported. Without those details and the primary result, readers cannot assess precision, completeness, or the extent to which the result might apply beyond the participants evaluated.
Accordingly, the most defensible interpretation is limited: the study was designed to examine correspondence between two ways of assessing gastric IM, but the registry record does not present the primary result needed to judge that correspondence. The accompanying tables and plots can be read for their displayed values, but no unreported result should be inferred from the study objective or background rationale.
9. Statistical Methods Explained
The registry identifies the primary outcome as percent agreement between acetic acid chromoendoscopy and endoscopic biopsy. Understanding that measure requires distinguishing agreement from other diagnostic statistics. Agreement asks whether two assessments produce matching classifications. It can be an intuitive summary, but it does not by itself indicate whether either assessment is correct. A diagnostic accuracy analysis typically compares a test result with a defined reference classification and reports measures that distinguish correct identification of findings from missed or incorrectly identified findings.
What does agreement summarize?
For this study, the endoscopist judged the presence and extent of gastric intestinal metaplasia during chromoendoscopy, while biopsy findings were assessed after tissue sampling and slide review. Percent agreement would summarize the proportion of lesion assessments that matched under the study's classification rules. The registry gives the endpoint unit as a percentage of lesions, but does not report the result or fully describe how lesions, categories, or disagreements were defined.
Agreement also needs context. If a finding is uncommon or common in the assessed material, a high overall match rate can arise partly from frequent agreement on the dominant category. Measures that account for agreement expected by chance may be used in some settings, but the registry does not say whether such a statistic was calculated. It would be inappropriate to assume that it was, or to treat the listed primary endpoint as a chance-corrected measure.
How does this differ from sensitivity and specificity?
The brief summary states that accuracy, sensitivity, and specificity were study aims. In general, sensitivity describes the extent to which a method identifies cases classified as positive by a reference, while specificity describes the extent to which it classifies reference-negative cases as negative. These measures require a defined positive and negative classification and a reference standard. The registry record does not report their estimates, confidence intervals, or the detailed classification rules. Nor does it explain whether accuracy was defined as overall agreement with biopsy or by another approach.
Biopsy was the comparison method for the primary endpoint, and the record says a pathologist reviewed the biopsy slides. That provides an important reference point, but the registry does not describe whether pathology review was blinded to the endoscopic assessment, how multiple biopsy samples contributed to lesion-level classifications, or how uncertain results were handled. General methodological caution applies: a comparison method is not necessarily error-free, and discrepancies can reflect limitations in either assessment or differences in what each method captures.
Why can observations within a participant matter?
The endpoint is expressed per lesion, and the procedure involved biopsies. If more than one lesion or sample contributed information for a participant, those observations could be related rather than statistically independent. In general, dependence among observations can affect the uncertainty around an estimate. The registry does not report the number of lesions per participant, how lesion-level observations were grouped, or whether the analysis accounted for within-participant clustering. This is a question to check in a full statistical report, not a detail that can be resolved from this record.
The record lists a secondary outcome assessing agreement between two endoscopists. Such an outcome can address consistency between readers, which differs from agreement between chromoendoscopy and biopsy. The registry does not report the statistic, estimate, or reading procedures used for this secondary outcome. It also does not state whether the two endoscopists assessed the same material independently.
The endpoint timeframe says that a pathologist reviewed all biopsy slides 3 months after completion of the study. That describes the stated timing of slide review, not the timing of the endoscopic assessment itself. The registry does not provide further details about data locking, adjudication, or whether review timing affected the analysis.
Finally, the calculated sample-size material should be read as planning illustration, not as observed power. General sample-size calculations describe the number of participants per arm that could be needed under stated assumptions to detect a specified effect with a chosen significance level and power. They do not establish the probability that this completed study found a real effect, and they are not a substitute for the observed estimate and its uncertainty. The assumptions described for the illustrations include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effect sizes defined as fractions of the observed effect. Those are properties of the illustrations, not reported design features of this single-group study. The registry record does not report the trial's own sample-size justification or statistical analysis plan.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists three outcome measures and three analyses, but the detailed analysis plan and numerical results for the primary and secondary outcomes are not reported in the registry record. The primary endpoint is percent agreement between chromoendoscopy and biopsy. The secondary outcomes are agreement between the two endoscopists and the number of participants with adverse events. The record does not explain whether these outcomes were tested together, whether any outcome was designated for formal hypothesis testing beyond the primary designation, or whether adjustments for multiple comparisons were planned.
Multiplicity matters when several outcomes or analyses are examined because the chance of at least one apparently notable finding can increase when many tests are conducted. This is a general statistical consideration, not evidence that the study did or did not apply a correction. No correction method, testing hierarchy, or prespecified handling of multiple analyses is reported in the registry record.
Missing-data methods and analysis populations are also not described. The enrollment was 126, while 105 participants are listed at risk in the adverse-event group. The reason for this difference is not reported in the registry record, and it should not be explained by assumption. The primary endpoint denominator, the number of participants or lesions with complete assessments, exclusions, and the handling of missing biopsies or readings are not reported. The record also does not identify an intention-to-treat or per-protocol analysis population. Consequently, the enrollment total cannot be treated as the denominator for the agreement analysis, and the completeness of the primary outcome cannot be assessed from the registry record.
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 |
|---|---|---|---|
| Acetic Acid Spraying | 0 | 105 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Acetic Acid Spraying | 11 of 105 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Acetic Acid Spraying |
|---|---|---|
| Epigastric discomfort | Gastrointestinal disorders | 9 of 105 |
| Odynophagia | Gastrointestinal disorders | 2 of 105 |
The adverse-event summary lists 105 participants at risk in the acetic acid spraying group. It reports zero serious adverse events and 11 participants with other adverse events. These figures should be read as the registry's posted counts for the listed group, not as a comparison between treatment arms; the study is single group and has no randomized control group.
The record does not provide serious adverse-event terms, and it does not list the specific other adverse-event terms in the information. It also does not report event severity details, timing, attribution, or whether participants could have experienced more than one event. The adverse-event outcome is described as the number of participants with adverse events, but the posted summary alone does not resolve all event-level details.
The 105 participants at risk is not the same as the enrollment of 126, and the reason for that difference is not reported in the registry record. The count of zero serious adverse events means that none are recorded in this posted summary for the stated group; it does not establish that no unrecorded or unmeasured events occurred. The count of 11 other adverse events should not be interpreted as a rate or percentage unless the relevant analysis and denominator are explicitly presented.
12. What the Result Does, and Does Not, Mean
This study asks a focused diagnostic-method question: whether judgments of gastric intestinal metaplasia made during acetic acid chromoendoscopy agree with biopsy assessments. The registry identifies percent agreement as the primary endpoint and describes the procedural comparison. However, the primary result is not reported in the registry record. As a result, the posted information does not establish how much agreement was observed or how precisely it was estimated.
The registry summary says that sensitivity, specificity, and accuracy were objectives, but their numerical findings are not reported. The background reference to accuracy greater than 80% concerns a pilot study described by the investigators, not the result of this completed study. It should not be used to fill the gap in the current study's results.
Even if an agreement estimate were available, it would describe correspondence under the study's assessments and classifications. It would not, by itself, demonstrate that the method improves patient outcomes, changes cancer risk, or is superior to another screening strategy. The registry does not report such outcomes or a randomized comparison. General interpretation of a diagnostic study also depends on how participants and lesions were selected, the reference method, the classification thresholds, and the handling of correlated or missing observations; many of these details are not reported in the registry record.
The posted safety summary records zero serious adverse events and 11 participants with other adverse events among 105 at risk in the acetic acid spraying group. These descriptive figures do not provide a comparison with an untreated or alternative-procedure group. The reasons for the distinction between the enrollment total and the safety denominator are not reported.
Overall, the registry record supports understanding what the investigators intended to evaluate and what data categories were posted. It does not contain the primary endpoint estimate needed to judge the observed agreement, nor does it contain the full diagnostic performance results identified as aims. Conclusions should therefore remain limited to the study question, recorded design, and posted safety counts.
13. Why This Trial Matters Statistically
This study is statistically interesting because it treats a diagnostic procedure as a measurement method and asks how its assessments correspond with a tissue-based comparison. That framing highlights an important distinction in clinical research: a method can be evaluated for agreement with another assessment without testing whether it changes outcomes. Clear separation of these questions helps prevent a diagnostic-method study from being interpreted as a treatment-effect trial.
The endpoint is expressed as a percentage of lesions, which raises a general design issue: the unit of analysis must match the way data were collected. When several observations can come from the same participant, they may be related. In general, analyses that treat related observations as independent can give misleading measures of uncertainty. The registry does not report the number of lesions or the method used to account for possible clustering, so that aspect cannot be assessed from the record.
The study also illustrates why an endpoint name is not enough to evaluate evidence. Percent agreement is readily understood, but its meaning depends on the classification rules and on how the comparison standard is used. Sensitivity and specificity answer different questions, and their interpretation requires clear definitions of positive and negative findings. The registry identifies these as aims but does not report their estimates or detailed methods.
Finally, the record contains a completed study designation and an enrollment figure but omits the central primary result. This makes transparent reporting especially important: without the estimate, its uncertainty, denominators, and analysis details, readers cannot assess the strength or precision of the evidence. Sample-size illustrations can help explore planning assumptions, but they cannot replace those observed results or serve as observed power.
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 most important limitation for interpreting this registry record is that the primary endpoint result is not reported. The record describes percent agreement between acetic acid chromoendoscopy and biopsy as the primary outcome, but does not provide the observed estimate or its uncertainty. The stated aims of accuracy, sensitivity, and specificity also lack reported estimates in the record.
The design is single group, with allocation listed as not applicable and masking listed as none. There is no randomized control group for a like-for-like comparison. This structure is consistent with a method-agreement question, but it cannot support a randomized comparison of competing procedures or a causal estimate of clinical benefit. The record does not report whether readers or the pathologist were blinded to other assessments.
The endpoint is defined per lesion, while enrollment is reported per participant. The number of lesions, the mapping of biopsies to lesions, and the statistical handling of multiple observations from the same participant are not reported. The record also does not describe classification thresholds, disagreement adjudication, or how extent was categorized. These omissions limit assessment of how reproducible or interpretable the planned agreement measure would be.
The registry reports enrollment of 126 and an adverse-event group at risk of 105, but does not explain the difference. The primary analysis denominator, missing-data handling, participant flow, and analysis populations are not reported. Eligibility criteria and participant characteristics are also absent from the record, limiting assessment of the population to which any result might apply.
Finally, the registry does not report the trial's sample-size justification, statistical analysis plan, multiplicity approach, or detailed results for the secondary outcomes. These details cannot be inferred from the presence of planning illustrations or from the study's stated objectives.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Acetic Acid Chromoendoscopy to Judge Gastric Intestinal Metaplasia — NCT01499576.
- Registry record last updated 2014-09-26; status last verified 2014-09.
- Results first posted 2014-09-26.
- 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
The registry describes a completed prospective, single-group study of acetic acid chromoendoscopy for judging the presence and extent of gastric intestinal metaplasia. Enrollment was 126. The study started in 2011-11 and reached primary completion in 2012-03. The sponsor is Konyang University Hospital.
The primary endpoint was percent agreement between chromoendoscopy and endoscopic biopsy, expressed as a percentage of lesions. The description states that the endoscopist performed five biopsies according to the protocol and that a pathologist reviewed the slides. The primary agreement result, along with numerical estimates for accuracy, sensitivity, and specificity, is not reported in the registry record.
The adverse-event summary lists 105 participants at risk, zero serious adverse events, and 11 participants with other adverse events in the acetic acid spraying group. The reason the safety denominator differs from enrollment is not reported. The record does not describe a randomized comparator, and it does not report the detailed analysis plan, analysis populations, or missing-data methods.