This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
IDEAL, the Initiation of Diet in Esophageal Varices After Ligation study, was a randomized, parallel-group clinical trial in liver cirrhosis. The study compared an early diet group with a late diet group, with the primary endpoint defined as an early rebleeding event within 5 days after esophageal variceal ligation.
| Feature | IDEAL |
|---|---|
| Study | Initiation of Diet in Esophageal Varices After Ligation (IDEAL) Study |
| Condition | Liver Cirrhosis |
| Phase | NA |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Primary purpose | Supportive care |
| Enrollment | 130 |
| Number of arms | 2 |
| Study status | Unknown |
| Study start | 2021-05-20 |
| Primary completion | 2021-11-01 |
| Lead sponsor | Dr Cipto Mangunkusumo General Hospital |
| Sponsor type | Other |
| ClinicalTrials.gov | NCT04890210 |
2. Clinical Question
The statistical question is whether the timing of dietary supplementation after esophageal variceal ligation is associated with the occurrence of an early rebleeding event during the first 5 days after the procedure.
Population
The registered condition is liver cirrhosis. The study enrollment was 130 participants.
Intervention
Early Diet Group, registered as a dietary-supplement intervention.
Comparator
Late Diet Group, also registered as a dietary-supplement intervention.
Primary question
Does the timing of diet after esophageal variceal ligation correspond to a difference in early rebleeding within 5 days?
3. Trial Design
Early Diet Group
- Registered intervention: dietary supplement
- Diet initiated according to the early-diet strategy
- Primary endpoint assessed after esophageal variceal ligation
Late Diet Group
- Registered intervention: dietary supplement
- Diet initiated according to the late-diet strategy
- Primary endpoint assessed after esophageal variceal ligation
Because allocation is randomized and the design is parallel, the central statistical comparison is between the frequency of the prespecified early-rebleeding outcome in the two randomized groups. The registry does not provide arm-specific enrollment counts, baseline characteristics, or outcome counts.
4. Endpoints
| Endpoint | Registry definition | Time frame |
|---|---|---|
| Early rebleeding event after esophageal variceal ligation | Early rebleeding event is hematemesis, melena and/or hematochezia that occurs within 5 days (120 hours) after esophageal variceal ligation. | This outcome will be assessed within 5 days after esophageal variceal ligation. |
What makes the primary endpoint statistically distinctive?
The endpoint is a binary clinical outcome defined within a fixed time window. Each participant can be classified according to whether an event meeting the registry definition occurred within the specified 5-day period.
The three manifestations named by the registry—hematemesis, melena and/or hematochezia—are part of the endpoint definition. The analysis should therefore preserve the registry's composite event definition rather than treating the individual manifestations as separate primary endpoints.
5. Statistical Methodology
The registry establishes a randomized, parallel-group design and a binary primary endpoint with a fixed assessment window. It does not report a posted statistical analysis for the primary endpoint. Results have not been posted on ClinicalTrials.gov.
Primary analysis framework
For a randomized comparison with an event defined as occurring or not occurring during a fixed follow-up window, the natural analysis is a comparison of event proportions between the two treatment groups. The statistical analysis would ordinarily begin with a two-by-two table containing randomized group and early rebleeding status.
The treatment effect can then be expressed using an absolute risk difference, a relative risk, or an odds ratio, depending on the prespecified statistical analysis.
Risk difference
The risk difference compares the observed event probability between the two groups. It is especially straightforward clinically because it expresses the absolute difference in the probability of an early rebleeding event during the registered time window.
A negative value would indicate a lower observed event proportion in the early-diet group; a positive value would indicate a higher observed event proportion.
Risk ratio
A risk ratio compares the event probability in the early-diet group with the event probability in the late-diet group. Unlike a risk difference, it describes the relative rather than absolute contrast.
A ratio below 1 would indicate a lower observed probability of early rebleeding in the early-diet group relative to the late-diet group.
Two-by-two hypothesis testing
Because the primary outcome is binary, a chi-square test or Fisher's exact test can be used to compare the event classifications between randomized groups. Fisher's exact test is particularly useful when expected cell counts are small. The choice should be specified prospectively rather than selected after seeing the event counts.
Confidence intervals
A point estimate alone does not describe statistical precision. A confidence interval around the selected treatment-effect measure shows the range of values reasonably compatible with the observed data under the statistical model and sampling framework.
For a binary endpoint such as early rebleeding, the most informative presentation would normally include the event count and denominator in each randomized group, the absolute event proportions, a treatment-effect measure such as risk difference or risk ratio, its confidence interval, and the corresponding hypothesis test. The registry does not post those numerical results.
6. Statistical Methods Explained
Why is early rebleeding treated as a binary endpoint?
The registry defines the primary outcome by whether hematemesis, melena and/or hematochezia occurs within a specified 5-day period after ligation. This creates a clinically interpretable event/no-event classification for each participant. Binary endpoints can be compared directly between randomized groups using proportions and contingency-table methods.
Why does the 5-day window matter?
The time window is part of the endpoint itself. A rebleeding event occurring after the registered 5-day period is not equivalent to an early rebleeding event as defined in this study. Fixed windows also make the denominators and observation period explicit when calculating event proportions.
Why use randomization for the treatment comparison?
Randomization establishes the treatment assignment mechanism before outcome assessment. When analyzed according to randomized assignment, the comparison can attribute observed differences in outcome rates to the randomized treatment strategy under the assumptions required for a valid randomized-trial analysis.
What does a risk difference tell us?
A risk difference describes the absolute contrast in event probability. For example, if one group had an event proportion of 0.10 and another had 0.20, the risk difference would be −0.10 when calculated as early minus late. The registry does not report the observed event proportions for IDEAL, so no numerical treatment effect can be stated.
What does a risk ratio tell us?
A risk ratio expresses one group's event probability relative to the other group's event probability. A value of 1 represents equal event probabilities, while values below or above 1 describe relative differences. Relative measures should be accompanied by absolute event proportions because a large relative difference can correspond to a small absolute difference when events are uncommon.
When would Fisher's exact test be useful?
Fisher's exact test is appropriate for a two-group binary comparison when the observed counts are small enough that large-sample approximations may be unreliable. A chi-square test is another standard approach for categorical comparisons when its approximation is adequate. The registry does not identify which test was prespecified for IDEAL.
Why is the confidence interval important?
The confidence interval describes statistical uncertainty around an estimated treatment effect. It should be read alongside the effect estimate and the observed event proportions rather than as a substitute for them. A narrow interval indicates greater statistical precision than a wide interval, all else being equal.
7. Planned Analysis
The registry says that the primary outcome is early rebleeding event after esophageal variceal ligation, assessed within 5 days after esophageal variceal ligation. The endpoint is defined as hematemesis, melena and/or hematochezia occurring within 5 days (120 hours) after the procedure.
| Analysis component | Statistical approach |
|---|---|
| Primary outcome | Binary early rebleeding event within the registered 5-day (120-hour) window. |
| Primary comparison | Compare the proportion of participants experiencing early rebleeding between the randomized early-diet and late-diet groups. |
| Effect measures | Risk difference and/or relative risk would provide direct measures of the between-group contrast; an odds ratio is another possible binary-outcome measure. |
| Hypothesis test | A chi-square or Fisher's exact test would typically be used for a two-group binary outcome, depending on observed cell counts and the prespecified analysis plan. |
| Precision | A confidence interval should accompany the selected treatment-effect estimate. |
| Interpretation | The analysis should remain tied to early rebleeding within 5 days (120 hours), rather than extending the endpoint to an unspecified period. |
8. Analysis Populations and Missing Outcome Data
The registry identifies the study as randomized and parallel with 130 enrolled participants, but it does not describe the analysis populations or provide an analysis-population definition for the primary endpoint.
For a randomized binary endpoint, an intention-to-treat analysis would ordinarily preserve participants according to their randomized treatment assignment. This approach maintains the treatment comparison created by randomization. A separate per-protocol or evaluable analysis, if prespecified, would answer a different question and could be more vulnerable to post-randomization selection.
Why missing outcome information matters
A fixed-window binary endpoint requires sufficient information to determine whether the event occurred during the relevant period. If outcome status is missing for some randomized participants, the handling of those participants can affect the estimated event proportions and potentially introduce bias.
The registry does not report a missing-data or imputation strategy. For a primary binary endpoint, common approaches can include explicit rules for unavailable outcome assessments, sensitivity analyses under different assumptions, or other prespecified methods. The appropriate strategy depends on why outcome information is missing and on the protocol and statistical analysis plan.
9. Effect Measures for the Primary Endpoint
Several measures can describe the same two-group binary comparison. They answer related but distinct statistical questions.
| Measure | What it describes | Key interpretation |
|---|---|---|
| Event proportion | Frequency of early rebleeding within each randomized group | Provides the absolute observed outcome burden in each group. |
| Risk difference | Absolute difference between event proportions | Directly describes how many more or fewer events occur per unit of population represented by the comparison. |
| Risk ratio | Ratio of event probabilities | Describes the relative event probability in one randomized group compared with the other. |
| Odds ratio | Ratio of event odds | Useful for binary regression and contingency-table analyses, but it is not the same as a risk ratio. |
Absolute effect
The risk difference is directly connected to the absolute frequency of early rebleeding and is therefore easy to relate to the fixed 5-day clinical window.
Relative effect
The risk ratio expresses the relative contrast between the two diet-timing strategies but can appear large even when the absolute event difference is modest.
10. Why This Endpoint Is Not a Kaplan-Meier Endpoint
The primary endpoint is defined as whether early rebleeding occurs within a fixed 5-day period. The registry does not define the primary outcome as time from ligation to rebleeding with a time-to-event estimand.
That distinction matters. If the scientific question were explicitly about time until rebleeding, survival-analysis methods such as Kaplan-Meier estimation and a Cox model could be appropriate. For the registered IDEAL endpoint, the primary classification is whether the prespecified event occurs within the specified window.
This is different from estimating a complete time-to-event distribution, where the exact event time and censoring information contribute to the analysis.
11. Randomization and Causal Interpretation
Randomization is the central design feature supporting a causal comparison between early and late diet strategies. If randomization is properly implemented and the analysis respects the randomized assignment, systematic differences in outcomes between the groups can be interpreted in relation to the assigned strategies rather than simply as observational associations.
What randomization supports
It creates a prospective comparison between treatment assignments and reduces the role of systematic baseline confounding in the treatment-group contrast.
What randomization does not guarantee
Randomization does not guarantee numerically identical groups or eliminate uncertainty. The observed comparison can still vary because of sampling variation.
The registry does not report baseline characteristics, group-specific enrollment counts, adherence information, or post-randomization deviations. Those details would be important when evaluating how closely the analyzed participants and treatments corresponded to the randomized design.
12. Single Masking and Outcome Assessment
The registry classifies IDEAL as single-masked. Masking can reduce the potential for knowledge of treatment assignment to influence behavior, assessment, or reporting, depending on which study participants or personnel are masked.
For a clinical endpoint involving hematemesis, melena and/or hematochezia, outcome ascertainment is particularly important. A prespecified and consistently applied endpoint definition helps maintain comparability between the randomized groups.
13. Multiplicity
The registered primary endpoint is a single composite clinical endpoint: early rebleeding event after esophageal variceal ligation. The registry information does not identify additional primary endpoints or a multiplicity-adjustment procedure.
The wording of the endpoint is also important. Hematemesis, melena and/or hematochezia are components of the single registered definition rather than separate primary endpoints in the registry record.
| Statistical issue | IDEAL interpretation |
|---|---|
| Primary endpoint | Early rebleeding event after esophageal variceal ligation. |
| Time frame | Within 5 days (120 hours) after esophageal variceal ligation. |
| Multiplicity across primary endpoints | The registry identifies one registered primary endpoint. |
| Multiplicity adjustment | Not reported in the registry information. |
| Secondary endpoint results | No posted statistical analyses are reported. |
14. Sample Size and Precision
The registry reports an enrollment of 130 participants. It does not report the planned event rate, treatment-effect assumption, power target, significance level, allocation ratio, or sample-size calculation.
For a binary endpoint, the statistical precision depends not only on the total number enrolled but also on the number of events and the distribution of participants between groups. A study with many participants can still produce an imprecise treatment-effect estimate when the event is uncommon.
For a binary endpoint, the number of observed events is a central determinant of the uncertainty surrounding an estimated treatment effect.
Consequently, the enrollment figure of 130 should not by itself be interpreted as evidence of a particular level of statistical power or precision.
15. Timeline
Study start
The registered study start date for IDEAL.
Primary completion
The registered primary completion date.
The registry classifies the current study status as Unknown. The record reports the study dates above but does not provide posted statistical outcome analyses.
16. Clinical Interpretation vs Statistical Interpretation
Statistical interpretation
The trial uses randomized parallel allocation to compare early and late diet strategies, with a binary primary outcome defined within a fixed 5-day window. The appropriate statistical comparison centers on between-group event proportions and their uncertainty.
Clinical interpretation
The clinical endpoint focuses on early rebleeding after esophageal variceal ligation, specifically defined by hematemesis, melena and/or hematochezia within 5 days (120 hours).
These are complementary perspectives. Statistical analysis quantifies the difference between randomized groups, while clinical interpretation determines what the endpoint represents in the context of the procedure and supportive-care strategy.
17. Limitations and Interpretation Issues
- No posted results: the ClinicalTrials.gov record does not report numerical primary-endpoint results, treatment-effect estimates, confidence intervals, or p-values.
- No posted statistical analysis: the registry does not specify the formal statistical test or effect measure used for the primary endpoint.
- Unknown analysis populations: the record does not describe the exact population used for primary-endpoint analysis.
- Unknown group sizes: total enrollment is 130, but the registry information does not provide the number assigned to each arm.
- No baseline characteristics: the registry information does not report baseline demographic or clinical characteristics by randomized group.
- Missing-data strategy not reported: the record does not specify how participants with unavailable outcome assessment would be handled.
- Masking detail: the registry identifies the study as single-masked but does not specify which study personnel or participants were masked.
- Fixed endpoint window: interpretation of the primary outcome must remain tied to the defined 5-day (120-hour) period after ligation.
- Composite clinical definition: hematemesis, melena and/or hematochezia are incorporated into the registered early-rebleeding definition and should not automatically be analyzed as separate primary endpoints.
18. What a Complete Primary-Endpoint Analysis Would Show
A transparent analysis of this trial's primary endpoint would begin with the randomized groups and the number of participants experiencing the registered early rebleeding event within the specified window.
| Analysis element | Purpose |
|---|---|
| Early Diet Group event count | Shows how many participants met the primary endpoint. |
| Late Diet Group event count | Provides the corresponding comparator outcome count. |
| Event proportion in each group | Shows the absolute frequency of early rebleeding. |
| Risk difference | Quantifies the absolute between-group difference. |
| Risk ratio or odds ratio | Quantifies the relative between-group contrast. |
| 95% confidence interval | Quantifies statistical precision around the selected effect estimate. |
| Hypothesis test | Assesses compatibility of the observed group difference with the null hypothesis under the selected test. |
This structure separates the observed outcome frequency from the effect estimate and from the statistical uncertainty. Those distinctions are essential when interpreting randomized binary endpoints.
19. Why This Trial Matters Statistically
IDEAL is a useful teaching example because it illustrates how a relatively simple randomized clinical question can require careful endpoint definition and disciplined statistical interpretation.
| Concept | How it appears in IDEAL |
|---|---|
| Randomization | Participants are allocated using a randomized design. |
| Parallel-group design | The trial has 2 parallel arms. |
| Binary endpoint | Early rebleeding is defined by whether the specified event occurs during the registered time window. |
| Fixed follow-up window | The primary outcome is assessed within 5 days (120 hours) after esophageal variceal ligation. |
| Risk difference | Provides an absolute comparison of early rebleeding frequency between randomized groups. |
| Risk ratio | Provides a relative comparison of event probabilities. |
| Contingency-table testing | Chi-square or Fisher's exact testing would ordinarily be considered for a two-group binary endpoint. |
| Confidence intervals | Quantify uncertainty around the estimated treatment effect. |
| Intention-to-treat principle | Provides a natural framework for preserving the randomized comparison when analyzing efficacy. |
| Missing outcomes | Outcome availability during the fixed assessment window can affect the validity and precision of the comparison. |
| Composite endpoint definition | Hematemesis, melena and/or hematochezia are incorporated into the registered early-rebleeding definition. |
20. Record Summary
IDEAL is a randomized, parallel-group study of 130 participants evaluating early versus late diet after esophageal variceal ligation in the setting of liver cirrhosis. Its primary endpoint is a clearly time-bounded binary clinical outcome: hematemesis, melena and/or hematochezia occurring within 5 days (120 hours) after esophageal variceal ligation.
From a statistical perspective, the key analysis is a comparison of the frequency of this event between the randomized early-diet and late-diet groups. Risk difference and relative measures such as risk ratio can describe the treatment contrast, while confidence intervals quantify precision and a suitable two-group categorical test can assess the corresponding null hypothesis.
The ClinicalTrials.gov record does not report the arm-specific outcome counts or any posted statistical analyses. As a result, the statistical interpretation of IDEAL is best centered on its randomized design, endpoint definition, fixed assessment window, and the principles required for a rigorous binary-outcome analysis.
21. Sources
- ClinicalTrials.gov: NCT04890210 — IDEAL Study.
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