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 The Effect of High Dose Vitamin C on the Liver Function in Chronic Hepatitis Patients (NCT01413360), a na phase 4 study. The primary outcome is The Change in Serum Alanine Aminotransferase Level From Baseline to 12 Weeks.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01413360 |
| Phase | Phase 4 |
| Condition | Chronic Hepatitis, Chronic Hepatitis C, Chronic Alcoholic Hepatitis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Seoul National University Hospital |
| Results posted | Yes |
2. Clinical Question
Population
Chronic hepatitis patients with elevated serum liver enzymes are the intended population described in the study summary. The listed conditions are chronic hepatitis, chronic hepatitis C, and chronic alcoholic hepatitis. The registry record does not report participant characteristics that would show how these conditions were represented among those enrolled, or how elevated enzyme levels were defined.
Intervention
The intervention is high dose vitamin C, recorded as a drug. The study summary describes evaluation of the intervention in chronic hepatitis patients. Dose details, administration schedule, and adherence information are not reported in the registry record.
Comparator
No separate comparator group is recorded. The study model is single group, and allocation is listed as not applicable. The record therefore does not describe a randomized comparison or a like-for-like control group.
Primary question
The primary outcome is the change in serum alanine aminotransferase, or ALT, from baseline to 12 weeks, measured in IU/L. The registry record identifies this as a within-group change question. It does not report the outcome values or an analysis result, so the magnitude, direction, and precision of any change cannot be described.
In statistical terms, the question is whether ALT values measured at the two stated time points differ within the study group. A within-group change can describe what happened over time among people receiving the intervention, but it cannot by itself separate a treatment-associated change from other explanations. Those explanations may include the natural course of illness, changes in other care, or measurement variability; whether any of these occurred in this study is not reported in the registry record.
The study summary refers to patients whose serum liver enzymes are elevated more than the upper limit. The precise eligibility definition and the enrolled participants’ baseline ALT distribution are not reported in the registry record. The planned observation period for the primary outcome is baseline and 12 weeks, and a secondary outcome concerns change in serum interleukin 22 over the same interval. No numerical results for either outcome are reported in the registry record.
3. Trial Design
The registry record classifies the study as Phase 4 and completed. It lists Seoul National University Hospital as the sponsor and gives enrollment as 10. The recorded study model is single group, allocation is not applicable, and masking is none. The intervention arm is named HD Vitamin C, with high dose vitamin C as its description. No separate control arm is recorded.
The study dates recorded are a start in 2011-08 and primary completion in 2013-12. These dates describe the registry record’s study timeline; they do not establish the timing of individual participants’ assessments or the length of follow-up beyond the specified primary endpoint timeframe. That endpoint is assessed at baseline and 12 weeks. The secondary outcome is change in serum interleukin 22 from baseline to 12 weeks.
A single-group design is suited to describing changes observed within the enrolled group, but it does not create a concurrent comparison against an untreated or differently treated group. Allocation and masking information are consistent with the record’s lack of a comparator: allocation is not applicable and masking is none. The registry record does not describe a randomization procedure, a control condition, or blinding of participants, clinicians, or outcome assessors.
The record lists two outcome measures and zero analyses. It does not report numerical outcome estimates, variability, confidence intervals, or hypothesis-test results. Consequently, the completion status and enrollment entry should not be mistaken for evidence that the primary question has a reported statistical answer. The protocol details, analysis plan, recruitment flow, participant-level follow-up, and reasons for any missing observations are not reported in the registry record.
The sample-size planning assumptions associated with the record describe a two-arm illustration with equal allocation, a two-sided significance level of 0.05, and a normal approximation. That is different from the recorded single-group study design. Such an illustration is not a description of the actual allocation, an observed comparison, or observed power. The registry record does not report the trial’s own sample-size justification or design calculations.
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 | HD Vitamin C |
|---|---|
| STARTED | 10 |
| COMPLETED | 7 |
| NOT COMPLETED | 3 |
Reasons for not completing this period:
| Reason | HD Vitamin C |
|---|---|
| Lost to Follow-up | 2 |
| Adverse Event | 1 |
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 | HD Vitamin C |
|---|---|---|
| Participants analysed | 10 | |
| Age, Continuous | years | 62 (39 to 70) |
| Sex: Female, Male: Female | Participants | 4 |
| Sex: Female, Male: Male | Participants | 6 |
| Region of Enrollment: Korea, Republic of | participants | 10 |
| Etiology: HCV | participants | 7 |
| Etiology: Alcohol | participants | 3 |
| ALT | IU/L | 65 (41 to 142) |
6. Primary Endpoint
The registry lists the primary outcome as The Change in Serum Alanine Aminotransferase Level From Baseline to 12 Weeks, measured over Baseline and 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | IU/L |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “The Change in Serum Alanine Aminotransferase Level From Baseline to 12 Weeks.” ALT is a serum liver enzyme, and its level is recorded in IU/L. The registry record specifies the measurement timeframe as baseline and 12 weeks and describes the endpoint as the serum ALT level after 12 weeks of high dose vitamin C administration and the baseline serum ALT level. It specifies a median as the summary measure and the full range as the dispersion measure.
As a general statistical matter, repeated measurements of a biomarker can describe how its distribution changes over a stated interval. A median gives the central value in an ordered set of measurements, while the full range describes the lowest and highest observed values. A range can convey the spread of observations, but it can be strongly affected by extreme values and does not show the full shape of the distribution. The registry record does not report the actual median or range values for either time point, nor a numerical estimate of the change.
ALT is used as the specified laboratory outcome for assessing liver function in the study’s stated clinical context. Its measurement is not itself a complete account of a participant’s health or of all aspects of liver disease. The record does not report how ALT was measured, whether a particular change threshold was considered meaningful, or how the analysis handled paired measurements. The absence of those details limits interpretation of the endpoint beyond its stated definition and timeframe.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a primary within-group outcome: change in serum ALT between baseline and 12 weeks. It does not report numerical ALT results or an analysis of that outcome. Therefore, there is no reported estimate from which to describe the direction or magnitude of change, and no reported interval or test result from which to assess statistical precision or compatibility with different values. The completed status indicates that the study is recorded as completed; it does not supply the missing outcome analysis.
The record lists 10 enrolled participants and a single intervention group. With no separate comparator, a change between measurements would describe a temporal pattern in that group rather than a contrast against another group. Even if a within-group difference had been reported, it would not on its own establish that the intervention caused the difference. General explanations for a before-and-after change include the intervention, the natural course of the condition, changes in other care, regression toward typical values after selection based on elevated measurements, and measurement variation. Which explanations apply cannot be determined from the registry record.
The primary outcome is specified as a median with full range, but the record contains no values for either. It also records zero analyses. These details mean that the registry entry does not offer a reported estimate to interpret, rather than showing that a particular effect is absent. A missing result is not evidence of no change, just as it is not evidence of a beneficial change. No claim about effectiveness or lack of effectiveness follows from the information recorded.
The secondary outcome is change in serum interleukin 22 from baseline to 12 weeks. Its numerical result and analysis are not reported in the registry record. No relationship between ALT and interleukin 22 can therefore be assessed. The record also does not report other clinical outcomes that might complement the laboratory measurements.
Statistical precision cannot be evaluated without an estimate and its uncertainty. In general, a confidence interval describes a range of values compatible with the data and analysis under its assumptions; it is not reported for the primary outcome in this record. A p-value, if one had been reported, would address compatibility with a specified statistical null model and would not by itself measure clinical importance or establish causality. No p-value is reported.
The sample-size assumptions describe a planning illustration based on an observed effect, with two-arm equal allocation and a two-sided significance level of 0.05. The record does not provide the effect value or analysis result needed to interpret such an illustration in relation to the outcome, and the two-arm assumptions do not match the recorded single-group design. The illustration must not be read as evidence of observed power, as a result from the trial, or as a substitute for a reported estimate with uncertainty.
9. Statistical Methods Explained
The record specifies a single-group model, no masking, and allocation as not applicable. In general, a single-group study observes participants under one recorded intervention condition rather than comparing outcomes between separately assigned intervention and control groups. Its primary endpoint is framed as change over time within that group. This design can describe measurements at the stated times, but it does not directly estimate a treatment contrast against a concurrent comparator. The registry record does not report a randomized allocation process, a control condition, or blinded outcome assessment.
The primary measure is ALT at baseline and 12 weeks, with the endpoint summary specified as a median and full range. In general, paired observations are measurements made on the same participant at more than one time. Analysis of change can use the pairing, which accounts for the fact that repeated values from one participant are related. The record does not report whether the analysis used participant-level paired differences, compared the two time-point distributions in another way, or applied any adjustment. Without the outcome values and analysis method, the numerical change cannot be reconstructed or evaluated.
A median describes the middle observation after values are ordered. The full range reports the extremes, and so shows the span between the minimum and maximum observed values. In general, this is a descriptive summary rather than a direct estimate of uncertainty around a group effect. It also does not show whether most values cluster near the median or are spread unevenly. The record gives no ALT summary values, no participant-level data, and no inferential estimate such as a confidence interval.
For a before-and-after study, it is important to distinguish description from causal inference. General statistical reasoning: an observed change over time may be associated with receiving an intervention, but without a suitable comparison it is difficult to distinguish that association from other time-related influences. Selection based on an initially elevated measurement can also make later values differ because unusually high measurements may not persist at the same level, even without a treatment effect. This is often called regression to the mean. The study summary describes elevated serum liver enzymes as part of the intended population, but the record does not establish how selection was operationalized or whether regression to the mean was addressed.
The listed sample-size assumptions describe a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They also describe detecting a stated fraction of an observed effect. General explanation: a planning calculation estimates how much information a future design might need under specified assumptions about the target effect, variability, allocation, and statistical test. It is not a result from participants and does not show the probability that this completed study found a true effect. That probability is sometimes incorrectly called observed power; planning illustrations are not observed power.
There is a design mismatch between those assumptions and the registry’s single-group model. Equal allocation between two arms is not the recorded trial structure, because no second arm is listed. The record does not report the trial’s own sample-size justification, the assumptions used to determine enrollment, or whether any planning calculation was used in conducting the study. Accordingly, the illustration should not be treated as an analysis of the actual study design.
General explanation: confidence intervals are useful because they show the range of effect estimates reasonably compatible with data and a specified model, while also making uncertainty visible. Their interpretation depends on the design and analysis being appropriate. A narrow interval generally indicates greater precision than a wide interval, but precision alone does not establish that an effect is important or causal. No confidence interval is reported for the primary endpoint in the registry record, so its precision cannot be assessed.
Likewise, a hypothesis test requires a defined null hypothesis and an analysis method. A p-value measures how unusual data at least as inconsistent with that null would be under the model’s assumptions; it does not give the probability that the null is true. No primary analysis or p-value is reported. Since the registry record lists zero analyses, statements about statistical significance, the strength of evidence, or an adjusted estimate would go beyond what is recorded.
The study lists two outcome measures: the primary ALT change and a secondary change in serum interleukin 22. In general, when multiple outcomes or analyses are tested, the chance of finding at least one apparently unusual result can increase. Methods for addressing multiplicity depend on which comparisons were planned and how conclusions are intended to be drawn. The registry record does not report a multiplicity plan or results for either outcome, so there is no basis to assess whether multiplicity was considered.
10. Multiplicity, Missing Data and Analysis Populations
The record lists two outcome measures: change in serum ALT as the primary outcome and change in serum interleukin 22 as a secondary outcome. It records zero analyses, and numerical results for these outcomes are not reported in the registry record. The analysis plan, including any prespecified testing order, multiplicity adjustment, or distinction between confirmatory and exploratory analyses, is not reported in the registry record.
In general, multiplicity matters when several outcomes, time points, or statistical tests can contribute to claims. Considering multiple tests without an appropriate plan can increase the chance that at least one result appears statistically notable by chance. Adjustments or hierarchical testing can address particular multiplicity concerns, but their suitability depends on the study question and prespecified plan. No such approach can be attributed to this study from the available record.
The registry record does not report missing-data counts for the primary or secondary outcomes, the number of participants with measurements at both time points, or reasons for missing measurements. It does not describe imputation, exclusions, sensitivity analyses, or a method for handling incomplete follow-up. Consequently, it is not possible to assess whether missing observations affected the reported outcome estimates; no such estimates are reported.
The analysis population is also not reported in the registry record. There is no description of whether analyses included all enrolled participants, only those with outcome measurements, or a separately defined population. No participant flow, protocol deviations, or analysis exclusions are recorded in the registry record for this interpretation. These omissions prevent evaluation of how the enrolled group relates to any analyzed group and whether the analysis followed a prespecified approach.
These are reporting gaps, not evidence that any particular method was or was not used in practice. The record’s completion status and enrollment entry do not resolve them. Clear reporting of outcome availability, analysis populations, and multiplicity decisions would be needed to assess the robustness and scope of any eventual result.
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 |
|---|---|---|---|
| HD Vitamin C | 0 | 10 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| HD Vitamin C | 1 of 10 |
Most frequent non-serious adverse event terms
| Event term | Organ system | HD Vitamin C |
|---|---|---|
| Dyspepsia | Gastrointestinal disorders | 1 of 10 |
The safety record describes one group, HD Vitamin C. It lists 10 participants at risk for serious adverse events and zero affected by serious adverse events. For other adverse events, it lists 10 at risk and one affected. These counts describe the registry’s recorded categories; they do not provide event details, timing, severity, or an assessment of whether an event was related to the intervention.
No top serious adverse event terms are listed. Deaths are not reported in the registry record. The absence of listed serious adverse event terms is consistent with the recorded count of zero affected by serious adverse events, but the record does not provide further information about how events were collected, defined, reviewed, or followed.
In general, adverse-event counts need to be interpreted in light of the group size, observation period, definitions, ascertainment procedures, and completeness of reporting. A small count cannot rule out uncommon harms, and a count alone cannot establish causation. The record does not give a detailed safety analysis or a comparison group, so these figures should be read as a limited descriptive report rather than as a comparative safety estimate.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed Phase 4, single-group study of high dose vitamin C in chronic hepatitis patients was registered, with enrollment listed as 10. It identifies change in serum ALT from baseline to 12 weeks as the primary endpoint and change in serum interleukin 22 over the same period as a secondary outcome. It also records limited adverse-event counts for the intervention group.
Those design and outcome details define what the study set out to assess, but the registry record does not report numerical results or analyses for either outcome. There is therefore no reported estimate of ALT change, no reported estimate of interleukin 22 change, and no uncertainty measure to judge precision. The available record cannot establish whether either measure increased, decreased, or remained similar over the specified interval.
Even if a within-group difference were available, the single-group design would not provide a direct comparison with a control group. In general, observed changes in a before-and-after study can reflect several influences, not only the intervention. The design therefore places limits on causal interpretation. The registry record does not report other data or design features that could address those limitations.
The safety entries show zero participants affected by serious adverse events and one affected by other adverse events in the listed group, with 10 at risk in each category. These descriptive counts do not establish whether an event was caused by the intervention, and the record does not report deaths, event descriptions, or a comparative safety analysis.
The sample-size assumptions are planning illustrations with two-arm assumptions, while the recorded study model is single group. They do not provide evidence of the study’s observed effect, statistical power, or outcome precision. The appropriate conclusion is limited: the registry record defines the study design, outcomes, and some safety counts, but it does not report the primary or secondary outcome analyses needed to characterize the observed results.
13. Why This Trial Matters Statistically
This study is statistically notable because its main question is framed as change from baseline in a single group, rather than as a difference between separately assigned groups. That distinction determines what the design can estimate. A within-group trajectory can be useful descriptive information, but it is not the same estimand as a comparative treatment effect. Readers need to keep the study model in view when interpreting any result, and in this record the numerical outcome results are not reported.
The endpoint is a biomarker measured at baseline and 12 weeks, summarized by median and full range. This makes the distribution and the paired nature of measurements relevant. General statistical reasoning: a change analysis should reflect the repeated measurements on the same participants, and its uncertainty should be presented in a way that matches the analysis. The registry record does not report the analysis method, values, or uncertainty, so those features cannot be evaluated.
The mismatch between the recorded single-group design and the stated two-arm planning assumptions is another important statistical point. Planning illustrations can be useful when their assumptions match the intended design, but an equal-allocation two-arm calculation does not describe a single-group study. Nor does a planning calculation indicate what the completed study observed. The record does not report the trial’s own sample-size justification.
Finally, the record lists two outcomes but no analyses. This underscores the difference between a registered outcome definition and a reported result. A clearly defined endpoint helps identify the intended question; interpretation still requires estimates, measures of uncertainty, analysis details, and information about missing data and the analysis population. Without those elements, conclusions about effect size, precision, significance, and robustness are not available from the registry record.
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.
Several limitations specific to this record restrict interpretation. The study is recorded as single group, with allocation not applicable and no masking. No separate comparator is listed. Therefore, the design does not report a concurrent comparison that could distinguish change over time in the intervention group from change under another condition.
The primary endpoint is clearly named and timed, but its numerical results and analysis are not reported in the registry record. The listed secondary outcome also has no reported result. The record gives zero analyses, so it does not support statements about the direction, magnitude, uncertainty, or statistical significance of either outcome. The median and full range are specified as summary measures, but their values are absent.
The record identifies chronic hepatitis, chronic hepatitis C, and chronic alcoholic hepatitis as conditions, while the study summary describes elevated serum liver enzymes. It does not report the enrolled group’s clinical characteristics, the distribution of conditions, baseline ALT values, or detailed eligibility criteria. The extent to which the enrolled participants represent any particular subgroup cannot be determined.
Intervention details beyond the name high dose vitamin C are not reported in the registry record. Dose, schedule, adherence, concomitant care, and measurement procedures are also not reported. Missing-data handling, the analysis population, protocol deviations, and a multiplicity plan are not reported. These omissions limit assessment of reproducibility and potential sources of bias.
The safety record provides counts but no event descriptions or comparative estimate. Deaths are not reported in the registry record. Finally, the two-arm planning assumptions do not match the single-group design, and the trial’s own sample-size justification is not reported. Together, these limitations mean the record is more informative about the registered question and design than about the study’s empirical findings.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Effect of High Dose Vitamin C on the Liver Function in Chronic Hepatitis Patients — NCT01413360.
- Registry record last updated 2016-07-15; status last verified 2016-06.
- Results first posted 2016-07-15.
- 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 record identifies NCT01413360 as a completed Phase 4 study sponsored by Seoul National University Hospital. It lists a single-group model, no masking, allocation as not applicable, and enrollment of 10. The intervention is high dose vitamin C in chronic hepatitis patients, including the listed conditions chronic hepatitis, chronic hepatitis C, and chronic alcoholic hepatitis. The recorded study start is 2011-08, and primary completion is 2013-12.
The primary outcome is change in serum ALT from baseline to 12 weeks, summarized by median and full range. The secondary outcome is change in serum interleukin 22 over the same timeframe. The record lists two outcome measures and zero analyses; numerical outcome results are not reported in the registry record.
For safety, the intervention group has zero participants affected by serious adverse events and one affected by other adverse events, with 10 at risk for each category. Deaths are not reported in the registry record. The record does not describe a comparator, detailed intervention regimen, analysis methods, or the trial’s own sample-size justification.